





















                                 [1mGNUPLOT[0m
                     [1mAn Interactive Plotting Program[0m



                      [4mThomas[24m [4mWilliams[24m [4m&[24m [4mColin[24m [4mKelley[0m
               [4mVersion[24m [4m4.1[24m [4morganized[24m [4mby:[24m [4mHans-Bernhard[24m [4mBroeker[0m
                   [4mMajor[24m [4mcontributors[24m [4m(alphabetic[24m [4morder):[0m
                           [4mHans-Bernhard[24m [4mBroeker[0m
                               [4mJohn[24m [4mCampbell[0m
                             [4mRobert[24m [4mCunningham[0m
                               [4mDavid[24m [4mDenholm[0m
                               [4mGershon[24m [4mElber[0m
                               [4mRoger[24m [4mFearick[0m
                              [4mCarsten[24m [4mGrammes[0m
                                 [4mLucas[24m [4mHart[0m
                                [4mLars[24m [4mHecking[0m
                               [4mThomas[24m [4mKoenig[0m
                                 [4mDavid[24m [4mKotz[0m
                                [4mEd[24m [4mKubaitis[0m
                                [4mRussell[24m [4mLang[0m
                             [4mAlexander[24m [4mLehmann[0m
                               [4mAlexander[24m [4mMai[0m
                               [4mEthan[24m [4mMerritt[0m
                                [4mPetr[24m [4mMikulik[0m
                               [4mCarsten[24m [4mSteger[0m
                                 [4mTom[24m [4mTkacik[0m
                             [4mJos[24m [4mVan[24m [4mder[24m [4mWoude[0m
                                  [4mAlex[24m [4mWoo[0m
                             [4mJames[24m [4mR.[24m [4mVan[24m [4mZandt[0m
                              [4mJohannes[24m [4mZellner[0m
     [4mCopyright[24m [4m(C)[24m [4m1986[24m [4m-[24m [4m1993,[24m [4m1998,[24m [4m2004[24m   [4mThomas[24m [4mWilliams,[24m [4mColin[24m [4mKelley[0m
        Mailing list for comments: gnuplot-info@lists.sourceforge.net
      Mailing list for bug reports: gnuplot-bugs@lists.sourceforge.net
                               22 June 2013



















                                    -2-








                This manual was prepared by Dick Crawford.
                             3 December 1998





























































   [1m1.  Gnuplot[0m





   [1m2.  Copyright[0m


       Copyright (C) 1986 - 1993, 1998, 2004, 2007  Thomas Williams,
   Colin Kelley

   Permission to use, copy, and distribute this software and its docu-
   mentation for any purpose with or without fee is hereby granted,
   provided that the above copyright notice appear in all copies and
   that both that copyright notice and this permission notice appear in
   supporting documentation.

   Permission to modify the software is granted, but not the right to
   distribute the complete modified source code.  Modifications are to
   be distributed as patches to the released version.  Permission to
   distribute binaries produced by compiling modified sources is
   granted, provided you
     1. distribute the corresponding source modifications from the
      released version in the form of a patch file along with the bina-
   ries,
     2. add special version identification to distinguish your version
      in addition to the base release version number,
     3. provide your name and address as the primary contact for the
      support of your modified version, and
     4. retain our contact information in regard to use of the base
      software.
   Permission to distribute the released version of the source code
   along with corresponding source modifications in the form of a patch
   file is granted with same provisions 2 through 4 for binary distri-
   butions.

   This software is provided "as is" without express or implied war-
   ranty to the extent permitted by applicable law.


         AUTHORS

         Original Software:










   GNUPLOT 4.1                                                        2


            Thomas Williams,  Colin Kelley.

         Gnuplot 2.0 additions:
            Russell Lang, Dave Kotz, John Campbell.

         Gnuplot 3.0 additions:
            Gershon Elber and many others.

         Gnuplot 4.0 additions:
            See list of contributors at head of this document.



   [1m3.  Introduction[0m


   [1mGnuplot [22mis a portable command-line driven graphing utility for
   Linux, OS/2, MS Windows, OSX, VMS, and many other platforms. The
   source code is copyrighted but freely distributed (i.e., you don't
   have to pay for it). It was originally created to allow scientists
   and students to visualize mathematical functions and data interac-
   tively, but has grown to support many non-interactive uses such as
   web scripting. It is also used as a plotting engine by third-party
   applications like Octave. Gnuplot has been supported and under
   active development since 1986.

   Gnuplot supports many types of plots in either 2D and 3D. It can
   draw using lines, points, boxes, contours, vector fields, surfaces,
   and various associated text. It also supports various specialized
   plot types.

   Gnuplot supports many different types of output: interactive screen
   terminals (with mouse and hotkey input), direct output to pen plot-
   ters or modern printers, and output to many file formats (eps, emf,
   fig, jpeg, LaTeX, pdf, png, postscript, ...). Gnuplot is easily
   extensible to include new output modes.  Recent additions include
   interactive terminals based on wxWidgets (usable on multiple plat-
   forms), and Qt.  Mouseable plots embedded in web pages can be gener-
   ated using the svg or HTML5 canvas terminal drivers.

   The command language of [1mgnuplot [22mis case sensitive, i.e. commands and
   function names written in lowercase are not the same as those writ-
   ten in capitals. All command names may be abbreviated as long as the
   abbreviation is not ambiguous. Any number of commands may appear on
   a line, separated by semicolons (;). Strings may be set off by
   either single or double quotes, although there are some subtle dif-
   ferences.  See [1msyntax [22mand [1mquotes [22mfor more details. Examples:

         load "filename"
         cd 'dir'

   Commands may extend over several input lines by ending each line but
   the last with a backslash (\).  The backslash must be the _last_










   GNUPLOT 4.1                                                        3


   character on each line.  The effect is as if the backslash and new-
   line were not there.  That is, no white space is implied, nor is a
   comment terminated.  Therefore, commenting out a continued line com-
   ments out the entire command (see [1mcomments[22m).  But note that if an
   error occurs somewhere on a multi-line command, the parser may not
   be able to locate precisely where the error is and in that case will
   not necessarily point to the correct line.

   In this document, curly braces ({}) denote optional arguments and a
   vertical bar (|) separates mutually exclusive choices.  [1mGnuplot [22mkey-
   words or [1mhelp [22mtopics are indicated by backquotes or [1mboldface [22m(where
   available).  Angle brackets (<>) are used to mark replaceable
   tokens.  In many cases, a default value of the token will be taken
   for optional arguments if the token is omitted, but these cases are
   not always denoted with braces around the angle brackets.

   For built-in help on any topic, type [1mhelp [22mfollowed by the name of
   the topic or [1mhelp ? [22mto get a menu of available topics.

   The new [1mgnuplot [22muser should begin by reading about [1mplotting [22m(if in
   an interactive session, type [1mhelp plotting[22m).

   See the simple.dem demo, also available together with other demos on
   the web page
             http://www.gnuplot.info/demo/
   [1mGnuplot [22mcan be started from a command line or from an icon according
   to the desktop environment. Running it from command line can take
   the syntax
         gnuplot {OPTIONS} file1 file2 ...
   where file1, file2, etc. are input file as in the [1mload [22mcommand.  On
   X11-based systems, you can use
         gnuplot {X11OPTIONS} {OPTIONS} file1 file2 ...
   see your X11 documentation and [1mx11 [22min this document.

   Options interpreted by gnuplot may come anywhere on the line.  Files
   are executed in the order specified, as are commands supplied by the
   -e option, for example
         gnuplot   file1.in   -e "reset"   file2.in

   The special filename "-" is used to force reading from stdin.  [1mGnu-[0m
   [1mplot [22mexits after the last file is processed.  If no load files are
   named, [1mGnuplot [22mtakes interactive input from stdin.  See help
   [1mbatch/interactive [22mfor more details.  The options specific to gnuplot
   can be listed by typing
         gnuplot --help
   See [1mcommand line options [22mfor more details.

   In sessions with an interactive plot window you can hit 'h' anywhere
   on the plot for help about [1mhotkeys [22mand [1mmousing [22mfeatures.  Section
   [1mseeking-assistance [22mwill help you to find further information, help
   and FAQ.












   GNUPLOT 4.1                                                        4


   [1m4.  Seeking-assistance[0m


   The canonical gnuplot web page can be found at
             http://www.gnuplot.info

   Before seeking help, please check file FAQ.pdf or the above website
   for
             FAQ (Frequently Asked Questions) list.

   If you need help as a gnuplot user, please use the newsgroup
             comp.graphics.apps.gnuplot
   We prefer that you read the messages through the newsgroup rather
   than subscribing to the mailing list which is also available and
   carries the same set of messages. Instructions for subscribing to
   gnuplot mailing lists may be found via the gnuplot development web-
   site on SourceForge
             http://sourceforge.net/projects/gnuplot

   The address for mailing to list members is:
             gnuplot-info@lists.sourceforge.net

   Bug reports and code contributions should be uploaded to the track-
   ers at
             http://sourceforge.net/projects/gnuplot/support
   Please check previous bug reports if the bug you want to report has
   not been already fixed in a newer version of gnuplot.

   A mailing list for those interested in development version of gnu-
   plot is:
             gnuplot-beta@lists.sourceforge.net

   When posting a question, please include full details of the gnuplot
   version, the terminal type, and the operating system you are using.
   A _small_ script demonstrating the problem may be useful.  Function
   plots are preferable to datafile plots.




   [1m5.  New features[0m


   This section lists major additions since version 4.4.  For a more
   exhaustive list, see the NEWS file.


















   GNUPLOT 4.1                                                        5


        [1m5.1.  New syntax[0m


        This version of gnuplot introduces command iteration and block-
        structured if/else/while/do constructs.  See [1mif[22m, [1mwhile[22m, and [1mdo[22m.
        Simple iteration is possible inside [1mplot [22mor [1mset [22mcommands.  See
        [1miteration[22m.  General iteration spanning multiple commands is
        possible using a block construct as shown below.  For a related
        new feature, see the [1msummation [22mexpression type.  Here is an
        example using several of these new syntax features:
              set multiplot layout 2,2
              fourier(k, x) = sin(3./2*k)/k * 2./3*cos(k*x)
              do for [power = 0:3] {
                  TERMS = 10**power
                  set title sprintf("%g term Fourier series",TERMS)
                  plot 0.5 + sum [k=1:TERMS] fourier(k,x) notitle
              }
              unset multiplot

        It is now possible to select a column of data from a data file
        by matching a label in the first row of the file. See [1mcolumn-[0m
        [1mhead[22m.  For example
              plot for [crop in "Oats Peas Beans"] 'data' using
        "Year":crop




        [1m5.2.  Local customization of linetypes[0m


        You can now customize properties (color, linewidth, point type)
        of the default sequence of linetypes used in plotting. See [1mset[0m
        [1mlinetype[22m.  This is normally done in an initialization file,
        either the system-wide file [1mgnuplotrc [22mor a private file [1m~/.gnu-[0m
        [1mplot[22m. See [1minitialization[22m.

        Most terminals now allow you to set an explicit background
        color for the plot.  The special linetype [1mbgnd [22mcan be used to
        draw in this color. See [1mbgnd[22m.




        [1m5.3.  New plot styles[0m


        See documentation for plot styles [1mboxplot[22m, [1mcircles[22m, [1mellipses[22m,
        and [1mfillsteps[22m.














   GNUPLOT 4.1                                                        6


        [1m5.4.  Revised polar axes[0m


        Polar plot mode has been reworked to support additional plot
        styles.  The polar axes can now be drawn and labeled indepen-
        dent of the x and y axes. See [1mset polar [22mand [1mset rrange[22m.




        [1m5.5.  New smoothing algorithms[0m


        New smoothing algorithms have been added for both 2- and
        3-dimensional plots.  [1msmooth kdensity [22mand [1msmooth cumulative [22mcan
        be used with [1mplot [22mto draw smooth histograms and cumulative dis-
        tribution functions.  Several new smoothing kernels have been
        added to [1mdgrid3d [22mfor use with [1msplot[22m.  See [1msmooth dgrid3d[22m.




        [1m5.6.  New time/date handling[0m


        Gnuplot now tracks time to millisecond precision. Time formats
        have been modified to match this. The new built-in function
        time() returns the current time of day according to the system
        clock.  Example: print the current time to msec precision
             print strftime("%H:%M:%.3S %d-%b-%Y",time(0.0))
             18:15:04.253 16-Apr-2011



        [1m5.7.  Statistical summary of data[0m


        The new [1mstats [22mcommand reads data from a file using the same
        syntax as the [1mplot [22mor [1msplot [22mcommands. Rather than drawing a
        graph, it prints out a statistical summary of the data con-
        tained in the column[s] requested.  The resulting statistics
        min, max, mean, standard deviation, correlation, etc. are also
        stored in named variables that can be used to compose or modify
        subsequent plotting commands.  See [1mstats[22m.




        [1m5.8.  New or revised terminal drivers[0m


        The [1mqt [22mdriver implements an interactive terminal on top of the
        Qt graphics layer.  It can function either as a window in a










   GNUPLOT 4.1                                                        7


        full-featured desktop enviroment or as a full-screen applica-
        tion on a Qt-based embedded device.  The [1mqt [22mterminal is new and
        may still have some rough edges.

        Two terminal types support web-based interactive display. The
        HTML5 [1mcanvas [22mterminal was introduced in version 4.4. The [1msvg[0m
        terminal has been extensively revised to include support for
        mousing and better incorporation of svg plots from gnuplot into
        larger svg/xml documents.

        The [1mcanvas [22mterminal driver produces javascript output that
        draws onto the HTML canvas element of a web page.  It can pro-
        duce either a complete web page containing a single plot, or a
        script that can be embedded as part of an externally generated
        HTML document that perhaps contains multiple plots.  The embed-
        ded plots support browser-side mousing, including zoom/unzoom.

        The [1mlua [22mterminal driver creates data intended to be further
        processed by a script in the lua programming language.  At this
        point only one such lua script, gnuplot-tikz.lua, is available.
        It produces a TeX document suitable for use with the latex TikZ
        package.  Other lua scripts could be written to process the
        gnuplot output for use with other TeX packages, or with other
        non-TeX tools.

        [1mset term tikz [22mis shorthand for [1mset term lua tikz[22m.  As decribed
        above, it uses the generic lua terminal and an external lua
        script to produce a latex document.

        The [1mcontext [22mterminal driver creates output to be further pro-
        cessed by the ConTeXt TeX macro package. To process its output,
        you additionally require the gnuplot module for ConTeXt avail-
        able at
                  http://ctan.org/pkg/context-gnuplot

        The [1mepscairo [22mterminal uses the cairo and pango libraries to
        create encapsulated postscript (eps) ouput. It is an alterna-
        tive to the [1mpostscript [22mterminal driver for those who would like
        to have their eps files look equal to e.g. screen output by the
        [1mwxt [22mterminal.

        The [1mcairolatex [22mterminal uses the cairo backend of the [1mpdfcairo[0m
        or [1mepscairo [22mterminal to produce graphs for inclusion in LaTeX
        documents. It creates pdf or eps graphics but transfers texts
        to LaTeX in the same way as the [1mepslatex [22mterminal.

        The [1mwindows [22mterminal driver has been revised to suport trans-
        parency, antialiasing, buffered output, multiple graph windows
        and copying to clipboard and saving of graphs as emf files. It
        has many new options and a revised user interface. Additionaly,
        the code of the text console has been largely rewritten to sup-
        port wrapping of long lines. Help is now provided via HTML.











   GNUPLOT 4.1                                                        8


   [1m6.  Backwards compatibility[0m


   Gnuplot version 4.0 deprecated certain syntax used in earlier ver-
   sions, but continued to recognize it.  This is now under the control
   of a configuration option, and can be enabled as follows:

         ./configure --enable-backwards-compatibility

   Notice: Deprecated syntax items may be removed entirely in some
   future version of gnuplot.

   One major difference is the introduction of keywords to disambiguate
   complex commands, particularly commands containing string variables.
   A notable issue was the use of bare numbers to specify offsets, line
   and point types.  Illustrative examples:

   Deprecated:
         set title "Old" 0,-1
         set data linespoints
         plot 1 2 4               # horizontal line at y=1
   New:
         TITLE = "New"
         set title TITLE offset char 0, char -1
         set style data linespoints
         plot 1 linetype 2 pointtype 4




   [1m7.  Batch/Interactive Operation[0m


   [1mGnuplot [22mmay be executed in either batch or interactive modes, and
   the two may even be mixed together on many systems.

   Any command-line arguments are assumed to be either program options
   (first character is -) or names of files containing [1mgnuplot [22mcom-
   mands. The option -e "command" may be used to force execution of a
   gnuplot command. Each file or command string will be executed in the
   order specified.  The special filename "-" is indicates that com-
   mands are to be read from stdin.  [1mGnuplot [22mexits after the last file
   is processed.  If no load files and no command strings are speci-
   fied, [1mgnuplot [22maccepts interactive input from stdin.

   Both the [1mexit [22mand [1mquit [22mcommands terminate the current command file
   and [1mload [22mthe next one, until all have been processed.

   Examples:

   To launch an interactive session:
         gnuplot











   GNUPLOT 4.1                                                        9


   To launch a batch session using two command files "input1" and
   "input2":
         gnuplot input1 input2

   To launch an interactive session after an initialization file
   "header" and followed by another command file "trailer":
         gnuplot header - trailer

   To give [1mgnuplot [22mcommands directly in the command line, using the
   "-persist" option so that the plot remains on the screen afterwards:
         gnuplot -persist -e "set title 'Sine curve'; plot sin(x)"

   To set user-defined variables a and s prior to executing commands
   from a file:
         gnuplot -e "a=2; s='file.png'" input.gpl




   [1m8.  Canvas size[0m



   In earlier versions of gnuplot, some terminal types used the values
   from [1mset size [22mto control also the size of the output canvas; others
   did not.  The use of 'set size' for this purpose was deprecated in
   version 4.2.  Since version 4.4 almost all terminals now behave as
   follows:

   [1mset term <terminal_type> size <XX>, <YY> [22mcontrols the size of the
   output file, or "canvas". Please see individual terminal documenta-
   tion for allowed values of the size parameters.  By default, the
   plot will fill this canvas.

   [1mset size <XX>, <YY> [22mscales the plot itself relative to the size of
   the canvas.  Scale values less than 1 will cause the plot to not
   fill the entire canvas.  Scale values larger than 1 will cause only
   a portion of the plot to fit on the canvas.  Please be aware that
   setting scale values larger than 1 may cause problems on some termi-
   nal types.

   The major exception to this convention is the PostScript driver,
   which by default continues to act as it has in earlier versions. Be
   warned that the next version of gnuplot may change the default be-
   haviour of the PostScript driver as well.

   Example:

         set size 0.5, 0.5
         set term png size 600, 400
         set output "figure.png"
         plot "data" with lines











   GNUPLOT 4.1                                                       10


   These commands will produce an output file "figure.png" that is 600
   pixels wide and 400 pixels tall. The plot will fill the lower left
   quarter of this canvas.  This is consistent with the way multiplot
   mode has always worked.




   [1m9.  Command-line-editing[0m


   Command-line editing and command history are supported using either
   an external gnu readline library, an external BSD libedit library,
   or a built-in equivalent.  This choice is a configuration option at
   the time gnuplot is built.

   The editing commands of the built-in version are given below. Please
   note that the action of the DEL key is system-dependent. The gnu
   readline and BSD libedit libraries have their own documentation.




      +-------------------------------------------------------------+
      |Character   Function                                         |
      +-------------------------------------------------------------+
      |            Line Editing                                     |
      |   ^B       move back a single character.                    |
      |   ^F       move forward a single character.                 |
      |   ^A       move to the beginning of the line.               |
      |   ^E       move to the end of the line.                     |
      |   ^H       delete the previous character.                   |
      |   DEL      delete the current character.                    |
      |   ^D       delete current character. EOF if line is empty.  |
      |   ^K       delete from current position to the end of line. |
      | ^L, ^R     redraw line in case it gets trashed.             |
      |   ^U       delete the entire line.                          |
      |   ^W       delete previous word.                            |
      +-------------------------------------------------------------+
      |            History                                          |
      |   ^P       move back through history.                       |
      |   ^N       move forward through history.                    |
      +-------------------------------------------------------------+






   [1m10.  Comments[0m













   GNUPLOT 4.1                                                       11


   Comments are supported as follows: a [1m# [22mmay appear in most places in
   a line and [1mgnuplot [22mwill ignore the rest of the line.  It will not
   have this effect inside quotes, inside numbers (including complex
   numbers), inside command substitutions, etc.  In short, it works
   anywhere it makes sense to work.

   See also [1mset datafile commentschars [22mfor specifying comment charac-
   ters in data files.  Note that if a comment line ends in '\' then
   the subsequent line is also treated as a comment.



   [1m11.  Coordinates[0m


   The commands [1mset arrow[22m, [1mset key[22m, [1mset label [22mand [1mset object [22mallow you
   to draw something at an arbitrary position on the graph.  This posi-
   tion is specified by the syntax:

         {<system>} <x>, {<system>} <y> {,{<system>} <z>}

   Each <system> can either be [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharac-[0m
   [1mter[22m.

   [1mfirst [22mplaces the x, y, or z coordinate in the system defined by the
   left and bottom axes; [1msecond [22mplaces it in the system defined by the
   second axes (top and right); [1mgraph [22mspecifies the area within the
   axes---0,0 is bottom left and 1,1 is top right (for splot, 0,0,0 is
   bottom left of plotting area; use negative z to get to the
   base---see [1mset xyplane[22m); [1mscreen [22mspecifies the screen area (the
   entire area---not just the portion selected by [1mset size[22m), with 0,0
   at bottom left and 1,1 at top right; and [1mcharacter [22mgives the posi-
   tion in character widths and heights from the bottom left of the
   screen area (screen 0,0), [1mcharacter [22mcoordinates depend on the chosen
   font size.

   If the coordinate system for x is not specified, [1mfirst [22mis used.  If
   the system for y is not specified, the one used for x is adopted.

   In some cases, the given coordinate is not an absolute position but
   a relative value (e.g., the second position in [1mset arrow [22m... [1mrto[22m).
   In most cases, the given value serves as difference to the first
   position.  If the given coordinate resides in a logarithmic axis the
   value is interpreted as factor. For example,

         set logscale x
         set arrow 100,5 rto 10,2

   plots an arrow from position 100,5 to position 1000,7 since the x
   axis is logarithmic while the y axis is linear.

   If one (or more) axis is timeseries, the appropriate coordinate
   should be given as a quoted time string according to the [1mtimefmt[0m










   GNUPLOT 4.1                                                       12


   format string.  See [1mset xdata [22mand [1mset timefmt[22m.  [1mGnuplot [22mwill also
   accept an integer expression, which will be interpreted as seconds
   from 1 January 2000.



   [1m12.  Datastrings[0m


   Data files may contain string data consisting of either an arbitrary
   string of printable characters containing no whitespace or an arbi-
   trary string of characters, possibly including whitespace, delimited
   by double quotes.  The following sample line from a datafile is
   interpreted to contain four columns, with a text field in column 3:

     1.000 2.000 "Third column is all of this text" 4.00

   Text fields can be positioned within a 2-D or 3-D plot using the
   commands:

     plot 'datafile' using 1:2:4 with labels
     splot 'datafile' using 1:2:3:4 with labels

   A column of text data can also be used to label the ticmarks along
   one or more of the plot axes. The example below plots a line through
   a series of points with (X,Y) coordinates taken from columns 3 and 4
   of the input datafile.  However, rather than generating regularly
   spaced tics along the x axis labeled numerically, gnuplot will posi-
   tion a tic mark along the x axis at the X coordinate of each point
   and label the tic mark with text taken from column 1 of the input
   datafile.

     set xtics
     plot 'datafile' using 3:4:xticlabels(1) with linespoints

   There is also an option that will interpret the first entry in a
   column of input data (i.e. the column heading) as a text field, and
   use it as the key title for data plotted from that column. The exam-
   ple given below will use the first entry in column 2 to generate a
   title in the key box, while processing the remainder of columns 2
   and 4 to draw the required line:

     plot 'datafile' using 1:(f($2)/$4) with lines title columnhead(2)

   Another example:

     plot for [i=2:6] 'datafile' using i title "Results for ".column-
   head(i)

   See [1mset style labels[22m, [1musing xticlabels[22m, [1mplot title[22m, [1musing[22m.













   GNUPLOT 4.1                                                       13


   [1m13.  Enhanced text mode[0m


   Many terminal types support an enhanced text mode in which addi-
   tional formatting information is embedded in the text string.  For
   example, "x^2" will write x-squared as we are used to seeing it,
   with a superscript 2.  This mode is normally selected when you set
   the terminal, e.g.  "set term png enhanced", but may also be toggled
   afterward using "set termoption enhanced", or by marking individual
   strings as in "set label 'x_2' noenhanced".




        +--------------------------------------------------------+
        |.lf 906  [4mCont[24mc[4mr[24me[4mo[24mn[4ml[24mtEexramb[4mc[24mpo[4mc[24mlx[4ml[24me.st[4mE[24ma[4mx[24mb[4mpl[24m([4ma[24m)[4mn[24m;[4mation[24m        ...[4mnnnrrr[24m333[4mbbbooottt888000[24m>>>???[4m888000[24m...|[4msssppp[24m|||[4m812060u00[24m.[4muu[24m3..[4mr[24m33[4mvrrpvvtpp[24m1[4mtt[24m.11[4ms[24m..[4mpss[24m|[4mpp8[24m||[4m088u00[24m.[4muun[24m..[4mrnn[24m3[4mrrb[24m33[4mrbburrluuell[24m1[4mee[24m.113..[4mr[24m3[4mversle[24m2[4melpae[24m>[4msa[24m?[4mes4[24m.[4me0[24m3.[4muk[24m3.[4mekleespe[24m1.[4mp[24m3.[4mr[24m3[4mmrkm[24m3[4mkr[24m3[4mtr[24m1[4mt[24m.2[4mn[24m.[4mrn[24m3[4mrc[24m3[4mrcorwo[24m1[4mw[24m.23.[4mk[24m3[4mekeepe[24m.[4mpm[24m.[4mkm[24m3[4mkr[24m3[4msr[24m1[4ms[24m.2[4mm[24m.[4mkm[24m3[4mkb[24m3[4mobto[24m.[4mt[24m3.[4mr[24m3[4mvrpvtp[24m0[4mt[24m.0[4mt[24m.[4mat1a013023u2[24m.[4mul[24m.[4mfl[24m8[4mf[24m28021
        |    & inserts space of specified length                 |
        | ~ [4ma[24m.8-overprints '-' on 'a', raised by .8              |
        |         times the current fontsize                     |
        +--------------------------------------------------------+




   Braces can be used to place multiple-character text where a single
   character is expected (e.g., 2^{10}).  To change the font and/or
   size, use the full form: {/[fontname][=fontsize | *fontscale] text}.
   Thus {/Symbol=20 G} is a 20 pt GAMMA and {/*0.75 K} is a K at three-
   quarters of whatever fontsize is currently in effect.  (The '/'
   character MUST be the first character after the '{'.)

   The phantom box is useful for a@^b_c to align superscripts and sub-
   scripts but does not work well for overwriting an accent on a let-
   ter.  For the latter, it is much better to use an encoding  (e.g.
   iso_8859_1 or utf8) that contains a large variety of letters with
   accents or other diacritical marks.  See [1mset encoding[22m. Since the box
   is non-spacing, it is sensible to put the shorter of the subscript
   or superscript in the box (that is, after the @).

   Space equal in length to a string can be inserted using the '&'
   character.  Thus
           'abc&{def}ghi'
   would produce
           'abc   ghi'.

   The '~' character causes the next character or bracketed text to be
   overprinted by the following character or bracketed text.  The sec-
   ond text will be horizontally centered on the first.  Thus '~a/'
   will result in an 'a' with a slash through it.  You can also shift
   the second text vertically by preceding the second text with a num-
   ber, which will define the fraction of the current fontsize by which
   the text will be raised or lowered.  In this case the number and
   text must be enclosed in brackets because more than one character is










   GNUPLOT 4.1                                                       14


   necessary.  If the overprinted text begins with a number, put a
   space between the vertical offset and the text ('~{abc}{.5 000}');
   otherwise no space is needed ('~{abc}{.5---}').  You can change the
   font for one or both strings ('~a{.5 /*.2 o}'---an 'a' with a one-
   fifth-size 'o' on top---and the space between the number and the
   slash is necessary), but you can't change it after the beginning of
   the string.  Neither can you use any other special syntax within
   either string.  You can, of course, use control characters by escap-
   ing them (see below), such as '~a{\^}'

   You can access special symbols numerically by specifying \character-
   code (in octal), e.g., {/Symbol \245} is the symbol for infinity.
   This does not work for multibyte encodings like UTF-8, however.  In
   a UTF-8 environment, you should be able to enter multibyte sequences
   implicitly by typing or otherwise selecting the character you want.

   You can escape control characters using \, e.g.,  \\, \{, and so on.

   But be aware that strings in double-quotes are parsed differently
   than those enclosed in single-quotes.  The major difference is that
   backslashes may need to be doubled when in double-quoted strings.

   Examples (these are hard to describe in words---try them!):
         set xlabel 'Time (10^6 {/Symbol m}s)'
         set title '{/Symbol=18 \\362@_{/=9.6 0}^{/=12 x}} \\
                    {/Helvetica e^{-{/Symbol m}^2/2} d}{/Symbol m}'

   The file "ps_guide.ps" in the /docs/psdoc subdirectory of the gnu-
   plot source distribution contains more examples of the enhanced syn-
   tax.



   [1m14.  Environment[0m


   A number of shell environment variables are understood by [1mgnuplot[22m.
   None of these are required, but may be useful.

   If GNUTERM is defined, it is used as the name of the terminal type
   to be used.  This overrides any terminal type sensed by [1mgnuplot [22mon
   start-up, but is itself overridden by the .gnuplot (or equivalent)
   start-up file (see [1mstartup[22m) and, of course, by later explicit
   changes.

   GNUHELP may be defined to be the pathname of the HELP file (gnu-
   plot.gih).

   On VMS, the logical name GNUPLOT$HELP should be defined as the name
   of the help library for [1mgnuplot[22m.  The [1mgnuplot [22mhelp can be put inside
   any system help library, allowing access to help from both within
   and outside [1mgnuplot [22mif desired.











   GNUPLOT 4.1                                                       15


   On Unix, HOME is used as the name of a directory to search for a
   .gnuplot file if none is found in the current directory.  On MS-DOS,
   Windows and OS/2, GNUPLOT is used.  On Windows, the NT-specific
   variable USERPROFILE is also tried. VMS, SYS$LOGIN: is used. Type
   [1mhelp startup[22m.

   On Unix, PAGER is used as an output filter for help messages.

   On Unix, SHELL is used for the [1mshell [22mcommand.  On MS-DOS and OS/2,
   COMSPEC is used for the [1mshell [22mcommand.

   FIT_SCRIPT may be used to specify a [1mgnuplot [22mcommand to be executed
   when a fit is interrupted---see [1mfit[22m.  FIT_LOG specifies the default
   filename of the logfile maintained by fit.

   GNUPLOT_LIB may be used to define additional search directories for
   data and command files. The variable may contain a single directory
   name, or a list of directories separated by a platform-specific path
   separator, eg. ':' on Unix, or ';' on DOS/Windows/OS/2 platforms.
   The contents of GNUPLOT_LIB are appended to the [1mloadpath [22mvariable,
   but not saved with the [1msave [22mand [1msave set [22mcommands.

   Several gnuplot terminal drivers access TrueType fonts via the gd
   library.  For these drivers the font search path is controlled by
   the environmental variable GDFONTPATH.  Furthermore, a default font
   for these drivers may be set via the environmental variable GNU-
   PLOT_DEFAULT_GDFONT.

   The postscript terminal uses its own font search path. It is con-
   trolled by the environmental variable GNUPLOT_FONTPATH. The format
   is the same as for GNUPLOT_LIB. The contents of GNUPLOT_FONTPATH are
   appended to the [1mfontpath [22mvariable, but not saved with the [1msave [22mand
   [1msave set [22mcommands.

   GNUPLOT_PS_DIR is used by the postscript driver to search for exter-
   nal prologue files. Depending on the build process, gnuplot contains
   either a built-in copy of those files or a default hardcoded path.
   You can use this variable have the postscript terminal use custom
   prologue files rather than the default files. See [1mpostscript pro-[0m
   [1mlogue[22m.



   [1m15.  Expressions[0m


   In general, any mathematical expression accepted by C, FORTRAN, Pas-
   cal, or BASIC is valid.  The precedence of these operators is deter-
   mined by the specifications of the C programming language.  White
   space (spaces and tabs) is ignored inside expressions.

   Complex constants are expressed as {<real>,<imag>}, where <real> and
   <imag> must be numerical constants.  For example, {3,2} represents 3










   GNUPLOT 4.1                                                       16


   + 2i; {0,1} represents 'i' itself.  The curly braces are explicitly
   required here.

   Note that gnuplot uses both "real" and "integer" arithmetic, like
   FORTRAN and C.  Integers are entered as "1", "-10", etc; reals as
   "1.0", "-10.0", "1e1", 3.5e-1, etc.  The most important difference
   between the two forms is in division: division of integers trun-
   cates: 5/2 = 2; division of reals does not: 5.0/2.0 = 2.5.  In mixed
   expressions, integers are "promoted" to reals before evaluation:
   5/2e0 = 2.5.  The result of division of a negative integer by a pos-
   itive one may vary among compilers.  Try a test like "print -5/2" to
   determine if your system chooses -2 or -3 as the answer.

   The integer expression "1/0" may be used to generate an "undefined"
   flag, which causes a point to ignored.  Or you can use the pre-
   defined variable NaN to achieve the same result.  See [1musing [22mfor an
   example.

   The real and imaginary parts of complex expressions are always real,
   whatever the form in which they are entered: in {3,2} the "3" and
   "2" are reals, not integers.

   Gnuplot can also perform simple operations on strings and string
   variables.  For example, the expression ("A" . "B" eq "AB") evalu-
   ates as true, illustrating the string concatenation operator and the
   string equality operator.

   A string which contains a numerical value is promoted to the corre-
   sponding integer or real value if used in a numerical expression.
   Thus ("3" + "4" == 7) and (6.78 == "6.78") both evaluate to true.
   An integer, but not a real or complex value, is promoted to a string
   if used in string concatenation.  A typical case is the use of inte-
   gers to construct file names or other strings; e.g. ("file" . 4 eq
   "file4") is true.

   Substrings can be specified using a postfixed range descriptor
   [beg:end].  For example, "ABCDEF"[3:4] == "CD"   and   "ABCDEF"[4:*]
   == "DEF" The syntax "string"[beg:end] is exactly equivalent to call-
   ing the built-in string-valued function substr("string",beg,end),
   except that you cannot omit either beg or end from the function
   call.




        [1m15.1.  Functions[0m


        The math functions in [1mgnuplot [22mare the same as the corresponding
        functions in the Unix math library, except that all functions
        accept integer, real, and complex arguments unless otherwise
        noted.  Functions that accept or return angles (e.g. sin(x),
        cos(x), arg(z)) treat angle values as radians, but this may be










   GNUPLOT 4.1                                                       17


        changed to degrees using the command [1mset angles[22m.






























































   GNUPLOT 4.1                                                       18


   +---------------------------------------------------------------------------------------------------+
   |   Function                Arguments            Returns                                            |
   +---------------------------------------------------------------------------------------------------+
   |    abs(x)                    any               absolute value of [4mx[24m, |[4mx[24m|; same type                |
   |    abs(x)                  complex             length of [4mx[24m, real([4mx[24m)2+imag([4mx[24m)2                     |
   |    acos(x)                   any               cos-1[4mx[24m (inverse cosine)                            |
   |   acosh(x)                   any               cosh-1[4mx[24m (inverse hyperbolic cosine) in radians     |
   |    airy(x)                   any               Airy function Ai(x)                                |
   |    arg(x)                  complex             the phase of [4mx[24m                                     |
   |    asin(x)                   any               sin-1[4mx[24m (inverse sin)                               |
   |   asinh(x)                   any               sinh-1[4mx[24m (inverse hyperbolic sin) in radians        |
   |    atan(x)                   any               tan-1[4mx[24m (inverse tangent)                           |
   |  atan2(y,x)              int or real           tan-1([4my[24m/[4mx[24m) (inverse tangent)                       |
   |   atanh(x)                   any               tanh-1[4mx[24m (inverse hyperbolic tangent) in radians    |
   | EllipticK(k)          real k in (-1:1)         [4mKk[24m complete elliptic integral of the first kind    |
   | EllipticE(k)          real k in [-1:1]          [4mEk[24m complete elliptic integral of the second kind  |
   |EllipticPi(n,k)    real n<1, real k in (-1:1)    [4mn[24m,[4mk[24m complete elliptic integral of the third kind  |
   |   besj0(x)               int or real           [4mj[24m0 Bessel function of [4mx[24m, in radians                |
   |   besj1(x)               int or real           [4mj[24m1 Bessel function of [4mx[24m, in radians                |
   |   besy0(x)               int or real           [4my[24m0 Bessel function of [4mx[24m, in radians                |
   |   besy1(x)               int or real           [4my[24m1 Bessel function of [4mx[24m, in radians                |
   |    ceil(x)                   any               [4mx[24m, smallest integer not less than [4mx[24m (real part)    |
   |    cos(x)                  radians             cos[4mx[24m, cosine of [4mx[24m                                  |
   |    cosh(x)                   any               cosh[4mx[24m, hyperbolic cosine of [4mx[24m in radians           |
   |    erf(x)                    any               [4merf[24m(real([4mx[24m)), error function of real ([4mx[24m)           |
   |    erfc(x)                   any               [4merfc[24m(real([4mx[24m)), 1.0 - error function of real ([4mx[24m)    |
   |    exp(x)                    any               [4mex[24m, exponential function of [4mx[24m                      |
   |  expint(n,x)                 any               [4mEn[24m([4mx[24m), exponential integral function of [4mx[24m          |
   |   floor(x)                   any               [4mx[24m, largest integer not greater than [4mx[24m (real part)  |
   |   gamma(x)                   any               (real([4mx[24m)), gamma function of real ([4mx[24m)              |
   | ibeta(p,q,x)                 any               [4mibeta[24m(real([4mp[24m,[4mq[24m,[4mx[24m)), ibeta function of real ([4mp[24m,[4mq[24m,[4mx[24m) |
   |   inverf(x)                  any               inverse error function real([4mx[24m)                     |
   |  igamma(a,x)                 any               [4migamma[24m(real([4ma[24m,[4mx[24m)), igamma function of real ([4ma[24m,[4mx[24m)   |
   |    imag(x)                 complex             imaginary part of [4mx[24m as a real number               |
   |  invnorm(x)                  any               inverse normal distribution function real([4mx[24m)       |
   |    int(x)                   real               integer part of [4mx[24m, truncated toward zero           |
   |  lambertw(x)                real               Lambert W function                                 |
   |   lgamma(x)                  any               [4mlgamma[24m(real([4mx[24m)), lgamma function of real ([4mx[24m)       |
   |    log(x)                    any               ln[4mx[24m, natural logarithm (base [4me[24m) of [4mx[24m               |
   |   log10(x)                   any               log10[4mx[24m, logarithm (base 10) of [4mx[24m                   |
   |    norm(x)                   any               [4mnorm[24m([4mx[24m), normal distribution function of real([4mx[24m)   |
   |    rand(x)                   int               pseudo random number in the interval [0:1]         |
   |    real(x)                   any               real part of [4mx[24m                                     |
   |    sgn(x)                    any               1 if [4mx[24m>0, -1 if [4mx[24m<0, 0 if [4mx[24m=0. imag([4mx[24m) ignored     |
   |    sin(x)                    any               sin[4mx[24m, sine of [4mx[24m                                    |
   |    sinh(x)                   any               sinh[4mx[24m, hyperbolic sine of [4mx[24m in radians             |
   |    sqrt(x)                   any               [4mx[24m, square root of [4mx[24m                                |
   |    tan(x)                    any               tan[4mx[24m, tangent of [4mx[24m                                 |
   |    tanh(x)                   any               tanh[4mx[24m, hyperbolic tangent of [4mx[24m in radians          |
   |  voigt(x,y)                 real               convolution of Gaussian and Lorentzian             |
   +---------------------------------------------------------------------------------------------------+












   GNUPLOT 4.1                                                       19


   +---------------------------------------------------------------------------------------------+
   |        Function            Arguments    Returns                                             |
   +---------------------------------------------------------------------------------------------+
   |gprintf("format",x,...)        any       string result from applying gnuplot's format parser |
   |sprintf("format",x,...)     multiple     string result from C-language sprintf               |
   |    strlen("string")         string      int length of string in bytes                       |
   |strstrt("string","key")      strings     int index of first character of substring "key"     |
   |substr("string",beg,end)    multiple     string "string"[beg:end]                            |
   |strftime("timeformat",t)       any       string result from applying gnuplot's time parser   |
   |strptime("timeformat",s)     string      seconds since year 2000 as given in string s        |
   |   system("command")         string      string containing output stream of shell command    |
   |    word("string",n)       string, int   returns the nth word in "string"                    |
   |    words("string")          string      returns the number of words in "string"             |
   +---------------------------------------------------------------------------------------------+






   +--------------------------------------------------------------------------------------------+
   |   Function         Arguments     Returns                                                   |
   +--------------------------------------------------------------------------------------------+
   |   column(x)      int or string    column [4mx[24m during datafile manipulation.                   |
   | columnhead(x)         int         string containing first entry of column [4mx[24m in datafile.   |
   |  defined(X)      variable name    [DEPRECATED] returns 1 if X is defined, 0 otherwise.     |
   |  exists("X")        string        returns 1 if a variable named X is defined, 0 otherwise. |
   |stringcolumn(x)   int or string    content column [4mx[24m as a string.                            |
   | timecolumn(x)         int         timecolumn [4mx[24m during datafile manipulation.               |
   |  tm_hour(x)           int        the hour                                                  |
   |  tm_mday(x)           int        the day of the month                                      |
   |   tm_min(x)           int        the minute                                                |
   |   tm_mon(x)           int        the month                                                 |
   |   tm_sec(x)           int        the second                                                |
   |  tm_wday(x)           int        the day of the week                                       |
   |  tm_yday(x)           int        the day of the year                                       |
   |  tm_year(x)           int        the year                                                  |
   |    time(x)            any        the current system time                                   |
   |   valid(x)            int         test validity of column([4mx[24m) during datafile manip.        |
   | value("name")       string        returns the current value of the named variable.         |
   +--------------------------------------------------------------------------------------------+







             [1m15.1.1.  Elliptic integrals[0m


             The [1mEllipticK(k) [22mfunction returns the complete elliptic
             integral of the first kind, i.e. the definite integral










   GNUPLOT 4.1                                                       20


             between 0 and pi/2 of the function
             [1m(1-(k*sin(p))**2)**(-0.5)[22m.  The domain of [1mk [22mis -1 to 1
             (exclusive).

             The [1mEllipticE(k) [22mfunction returns the complete elliptic
             integral of the second kind, i.e. the definite integral
             between 0 and pi/2 of the function [1m(1-(k*sin(p))**2)**0.5[22m.
             The domain of [1mk [22mis -1 to 1 (inclusive).

             The [1mEllipticPi(n,k) [22mfunction returns the complete elliptic
             integral of the third kind, i.e. the definite integral
             between 0 and pi/2 of the function
             [1m(1-(k*sin(p))**2)**(-0.5)/(1-n*sin(p)**2)[22m.  The parameter
             [1mn [22mmust be less than 1, while [1mk [22mmust lie between -1 and 1
             (exclusive).  Note that by definition EllipticPi(0,k) ==
             EllipticK(k) for all possible values of [1mk[22m.



             [1m15.1.2.  Random number generator[0m


             The function [1mrand() [22mproduces a sequence of pseudo-random
             numbers between 0 and 1 using an algorithm from P.
             L'Ecuyer and S. Cote, "Implementing a random number pack-
             age with splitting facilities", ACM Transactions on Mathe-
             matical Software, 17:98-111 (1991).

                   rand(0)     returns a pseudo random number in the
             interval [0:1]
                               generated from the current value of two
             internal
                               32-bit seeds.
                   rand(-1)    resets both seeds to a standard value.
                   rand(x)     for integer 0 < x < 2^31-1 sets both
             internal seeds
                               to x.
                   rand({x,y}) for integer 0 < x,y < 2^31-1 sets seed1
             to x and
                               seed2 to y.



             [1m15.1.3.  Value[0m


             B = value("A") is effectively the same as B = A, where A
             is the name of a user-defined variable.  This is useful
             when the name of the variable is itself held in a string
             variable. See [1muser-defined variables[22m.  It also allows you
             to read the name of a variable from a data file.  If the
             argument is a numerical expression, value() returns the
             value of that expression.  If the argument is a string










   GNUPLOT 4.1                                                       21


             that does not correspond to a currently defined variable,
             value() returns NaN.




        [1m15.2.  Operators[0m


        The operators in [1mgnuplot [22mare the same as the corresponding
        operators in the C programming language, except that all opera-
        tors accept integer, real, and complex arguments, unless other-
        wise noted.  The ** operator (exponentiation) is supported, as
        in FORTRAN.

        Parentheses may be used to change order of evaluation.




             [1m15.2.1.  Unary[0m


             The following is a list of all the unary operators and
             their usages:







    +-----------------------------------------------------------------+
    |Symbol   Example   Explanation                                   |
    +-----------------------------------------------------------------+
    |  -        -a      unary minus                                   |
    |  +        +a      unary plus (no-operation)                     |
    |  ~        ~a      * one's complement                            |
    |  !        !a      * logical negation                            |
    |  !        a!      * factorial                                   |
    |  $        $3      * call arg/column during `using` manipulation |
    +-----------------------------------------------------------------+
    +-----------------------------------------------------------------+




   (*) Starred explanations indicate that the operator requires an
   integer argument.

   Operator precedence is the same as in Fortran and C.  As in those
   languages, parentheses may be used to change the order of operation.
   Thus -2**2 = -4, but (-2)**2 = 4.










   GNUPLOT 4.1                                                       22


   The factorial operator returns a real number to allow a greater
   range.



             [1m15.2.2.  Binary[0m


             The following is a list of all the binary operators and
             their usages:




              +--------------------------------------------+
              |Symbol   Example   Explanation              |
              +--------------------------------------------+
              |  **      a**b     exponentiation           |
              |  *        a*b     multiplication           |
              |  /        a/b     division                 |
              |  %        a%b     * modulo                 |
              |  +        a+b     addition                 |
              |  -        a-b     subtraction              |
              |  ==      a==b     equality                 |
              |  !=      a!=b     inequality               |
              |  <        a<b     less than                |
              |  <=      a<=b     less than or equal to    |
              |  >        a>b     greater than             |
              |  >=      a>=b     greater than or equal to |
              |  &        a&b     * bitwise AND            |
              |  ^        a^b     * bitwise exclusive OR   |
              |  |        a|b     * bitwise inclusive OR   |
              |  &&      a&&b     * logical AND            |
              |  ||      a||b     * logical OR             |
              +--------  a = b    assignment               |
              |  ,       (a,b)    serial evaluation        |
              |  eq     A eq B    string equality          |
              |  ne     A ne B    string inequality        |
              +--------------------------------------------+




   (*) Starred explanations indicate that the operator requires integer
   arguments.  Capital letters A and B indicate that the operator
   requires string arguments.

   Logical AND (&&) and OR (||) short-circuit the way they do in C.
   That is, the second [1m&& [22moperand is not evaluated if the first is
   false; the second [1m|| [22moperand is not evaluated if the first is true.

   Serial evaluation occurs only in parentheses and is guaranteed to
   proceed in left to right order.  The value of the rightmost










   GNUPLOT 4.1                                                       23


   subexpression is returned.



             [1m15.2.3.  Ternary[0m


             There is a single ternary operator:




                 +---------------------------------------+
                 |Symbol   Example   Explanation         |
                 +---------------------------------------+
                 |  ?:      a?b:c    * ternary operation |
                 +---------------------------------------+




   The ternary operator behaves as it does in C.  The first argument
   (a), which must be an integer, is evaluated.  If it is true (non-
   zero), the second argument (b) is evaluated and returned; otherwise
   the third argument (c) is evaluated and returned.

   The ternary operator is very useful both in constructing piecewise
   functions and in plotting points only when certain conditions are
   met.

   Examples:

   Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <=
   x < 2, and undefined elsewhere:
         f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
         plot f(x)
   Note that [1mgnuplot [22mquietly ignores undefined values, so the final
   branch of the function (1/0) will produce no plottable points.  Note
   also that f(x) will be plotted as a continuous function across the
   discontinuity if a line style is used.  To plot it discontinuously,
   create separate functions for the two pieces.  (Parametric functions
   are also useful for this purpose.)

   For data in a file, plot the average of the data in columns 2 and 3
   against the datum in column 1, but only if the datum in column 4 is
   non-negative:

         plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )

   For an explanation of the [1musing [22msyntax, please see [1mplot datafile[0m
   [1musing[22m.












   GNUPLOT 4.1                                                       24


        [1m15.3.  Summation[0m


        A summation expression has the form
              sum [<var> = <start> : <end>] <expression>
        <var> is treated as an integer variable that takes on succes-
        sive integral values from <start> to <end>.  For each of these,
        the current value of <expression> is added to a running total
        whose final value becomes the value of the summation expres-
        sion.  Examples:
              print sum [i=1:10] i
                  55.
              # Equivalent to plot 'data' using 1:($2+$3+$4+$5+$6+...)
              plot 'data' using 1 : (sum [col=2:MAXCOL] column(col))
        It is not necessary that <expression> contain the variable
        <var>.  Although <start> and <end> can be specified as vari-
        ables or expressions, their value cannot be changed dynamically
        as a side-effect of carrying out the summation. If <end> is
        less than <start> then the value of the summation is zero.



        [1m15.4.  Gnuplot-defined variables[0m


        Gnuplot maintains a number of read-only variables that reflect
        the current internal state of the program and the most recent
        plot. These variables begin with the prefix "GPVAL_".  Examples
        include GPVAL_TERM, GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN.
        Type [1mshow variables all [22mto display the complete list and cur-
        rent values.  Values related to axes parameters (ranges, log
        base) are values used during the last plot, not those currently
        [1mset[22m.

        Example:  To calculate the fractional screen coordinates of the
        point [X,Y]
             GRAPH_X = (X - GPVAL_X_MIN) / (GPVAL_X_MAX - GPVAL_X_MIN)
             GRAPH_Y = (Y - GPVAL_Y_MIN) / (GPVAL_Y_MAX - GPVAL_Y_MIN)
             SCREEN_X = GPVAL_TERM_XMIN + GRAPH_X * (GPVAL_TERM_XMAX -
        GPVAL_TERM_XMIN)
             SCREEN_Y = GPVAL_TERM_YMIN + GRAPH_Y * (GPVAL_TERM_YMAX -
        GPVAL_TERM_YMIN)
             FRAC_X = SCREEN_X / GPVAL_TERM_XSIZE
             FRAC_Y = SCREEN_Y / GPVAL_TERM_YSIZE

        The read-only variable GPVAL_ERRNO is set to a non-zero value
        if any gnuplot command terminates early due to an error.  The
        most recent error message is stored in the string variable
        GPVAL_ERRMSG.  Both GPVAL_ERRNO and GPVAL_ERRMSG can be cleared
        using the command [1mreset errors[22m.

        Interactive terminals with [1mmouse [22mfunctionality maintain read-
        only variables with the prefix "MOUSE_".  See [1mmouse variables[0m










   GNUPLOT 4.1                                                       25


        for details.

        The [1mfit [22mmechanism uses several variables with names that begin
        "FIT_".  It is safest to avoid using such names.  "FIT_LIMIT",
        however, is one that you may wish to redefine. Under [1mset fit[0m
        [1merrorvariables[22m, the error for each fitted parameter will be
        stored in a variable named like the parameter, but with "_err"
        appended. See the documentation on [1mfit [22mfor details.

        See [1muser-defined variables[22m, [1mreset errors[22m, [1mmouse variables[22m, and
        [1mfit[22m.




        [1m15.5.  User-defined variables and functions[0m


        New user-defined variables and functions of one through twelve
        variables may be declared and used anywhere, including on the
        [1mplot [22mcommand itself.

        User-defined function syntax:
              <func-name>( <dummy1> {,<dummy2>} ... {,<dummy12>} ) =
        <expression>

        where <expression> is defined in terms of <dummy1> through
        <dummy12>.

        User-defined variable syntax:
              <variable-name> = <constant-expression>

        Examples:
              w = 2
              q = floor(tan(pi/2 - 0.1))
              f(x) = sin(w*x)
              sinc(x) = sin(pi*x)/(pi*x)
              delta(t) = (t == 0)
              ramp(t) = (t > 0) ? t : 0
              min(a,b) = (a < b) ? a : b
              comb(n,k) = n!/(k!*(n-k)!)
              len3d(x,y,z) = sqrt(x*x+y*y+z*z)
              plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)

              file = "mydata.inp"
              file(n) = sprintf("run_%d.dat",n)

        The final two examples illustrate a user-defined string vari-
        able and a user-defined string function.

        Note that the variables [1mpi [22m(3.14159...) and [1mNaN [22m(IEEE "Not a
        Number") are already defined.  You can redefine these to some-
        thing else if you really need to. The original values can be










   GNUPLOT 4.1                                                       26


        recovered by setting:

              NaN = GPVAL_NaN
              pi  = GPVAL_pi

        Other variables may be defined under various gnuplot operations
        like mousing in interactive terminals or fitting; see [1mgnuplot-[0m
        [1mdefined variables [22mfor details.

        You can check for existence of a given variable V by the
        exists("V") expression. For example
              a = 10
              if (exists("a")) print "a is defined"
              if (!exists("b")) print "b is not defined"

        Valid names are the same as in most programming languages: they
        must begin with a letter, but subsequent characters may be let-
        ters, digits, or "_".

        Each function definition is made available as a special string-
        valued variable with the prefix 'GPFUN_'.

        Example:
              set label GPFUN_sinc at graph .05,.95

        See [1mshow functions[22m, [1mfunctions[22m, [1mgnuplot-defined variables[22m,
        [1mmacros[22m, [1mvalue[22m.



   [1m16.  Fonts[0m


   Gnuplot does not provide any fonts of its own. It relies on external
   font handling, the details of which unfortunately vary from one ter-
   minal type to another. Brief documentation of font mechanisms that
   apply to more than one terminal type is given here. For information
   on font use by other individual terminals, see the documentation for
   that terminal.




        [1m16.1.  Cairo (pdfcairo, pngcairo, epscairo, wxt terminals)[0m


        Sorry, this section is under construction.  These terminals
        find and access fonts using the external fontconfig tool set.
        Please see the fontconfig user manual.  It is usually suffi-
        cient in gnuplot to request a font by a generic name and size,
        letting fontconfig substitute a similar font if necessary. The
        following will probably all work:
             set term pdfcairo font "sans,12"










   GNUPLOT 4.1                                                       27


             set term pdfcairo font "Times,12"
             set term pdfcairo font "Times-New-Roman,12"




        [1m16.2.  Gd (png, gif, jpeg terminals)[0m


        Font handling for the png, gif, and jpeg terminals is done by
        the external library libgd.  Five basic fonts are provided
        directly by libgd. These are [1mtiny [22m(5x8 pixels), [1msmall [22m(6x12
        pixels), [1mmedium[22m, (7x13 Bold), [1mlarge [22m(8x16) or [1mgiant [22m(9x15 pix-
        els). These fonts cannot be scaled or rotated.  Use one of
        these keywords instead of the [1mfont [22mkeyword. E.g.
             set term png tiny

        On most systems libgd also provides access to Adobe Type 1
        fonts (*.pfa) and TrueType fonts (*.ttf). You must give the
        name of the font file, not the name of the font inside it, in
        the form "<face> {,<pointsize>}".  <face> is either the full
        pathname to the font file, or the first part of a filename in
        one of the directories listed in the GDFONTPATH environmental
        variable. That is, 'set term png font "Face"' will look for a
        font file named either <somedirectory>/Face.ttf or <somedirec-
        tory>/Face.pfa.  For example, if GDFONTPATH contains
        [1m/usr/local/fonts/ttf:/usr/local/fonts/pfa [22mthen the following
        pairs of commands are equivalent
             set term png font "arial"
             set term png font "/usr/local/fonts/ttf/arial.ttf"
             set term png font "Helvetica"
             set term png font "/usr/local/fonts/pfa/Helvetica.pfa"
        To request a default font size at the same time:
             set term png font "arial,11"

        Both TrueType and Adobe Type 1 fonts are fully scalable and
        rotatable.  If no specific font is requested in the "set term"
        command, gnuplot checks the environmental variable GNU-
        PLOT_DEFAULT_GDFONT to see if there is a preferred default
        font.



        [1m16.3.  Postscript  (also encapsulated postscript *.eps)[0m


        PostScript font handling is done by the printer or viewing pro-
        gram.  Gnuplot can create valid PostScript or encapsulated
        PostScript (*.eps) even if no fonts at all are installed on
        your computer.  Gnuplot simply refers to the font by name in
        the output file, and assumes that the printer or viewing pro-
        gram will know how to find or approximate a font by that name.











   GNUPLOT 4.1                                                       28


        All PostScript printers or viewers should know about the stan-
        dard set of Adobe fonts [1mTimes-Roman[22m, [1mHelvetica[22m, [1mCourier[22m, and
        [1mSymbol[22m.  It is likely that many additional fonts are also
        available, but the specific set depends on your system or
        printer configuration. Gnuplot does not know or care about
        this; the output *.ps or *.eps files that it creates will sim-
        ply refer to whatever font names you request.

        Thus
             set term postscript eps font "Times-Roman,12"
        will produce output that is suitable for all printers and view-
        ers.

        On the other hand
             set term postscript eps font "Garamond-Premier-Pro-Italic"
        will produce an output file that contains valid PostScript, but
        since it refers to a specialized font, only some printers or
        viewers will be able to display the specific font that was
        requested.  Most will substitute a different font.

        However, it is possible to embed a specific font in the output
        file so that all printers will be able to use it. This requires
        that the a suitable font description file is available on your
        system. Note that some font files require specific licensing if
        they are to be embedded in this way.  See [1mpostscript fontfile[0m
        for more detailed description and examples.



   [1m17.  Glossary[0m


   Throughout this document an attempt has been made to maintain con-
   sistency of nomenclature.  This cannot be wholly successful because
   as [1mgnuplot [22mhas evolved over time, certain command and keyword names
   have been adopted that preclude such perfection.  This section con-
   tains explanations of the way some of these terms are used.

   A "page" or "screen" or "canvas" is the entire area addressable by
   [1mgnuplot[22m.  On a desktop it is a full window; on a plotter, it is a
   single sheet of paper; in svga mode it is the full monitor screen.

   A screen may contain one or more "plots".  A plot is defined by an
   abscissa and an ordinate, although these need not actually appear on
   it, as well as the margins and any text written therein.

   A plot contains one "graph".  A graph is defined by an abscissa and
   an ordinate, although these need not actually appear on it.

   A graph may contain one or more "lines".  A line is a single func-
   tion or data set.  "Line" is also a plotting style.  The word will
   also be used in sense "a line of text".  Presumably the context will
   remove any ambiguity.










   GNUPLOT 4.1                                                       29


   The lines on a graph may have individual names.  These may be listed
   together with a sample of the plotting style used to represent them
   in the "key", sometimes also called the "legend".

   The word "title" occurs with multiple meanings in [1mgnuplot[22m.  In this
   document, it will always be preceded by the adjective "plot",
   "line", or "key" to differentiate among them.  A 2D graph may have
   up to four labelled [1maxes[22m.  The names of the four axes are "x" for
   the axis along the bottom border of the plot, "y" for the axis along
   the left border, "x2" for the top border, and "y2" for the right
   border.  See [1maxes[22m.

   A 3D graph may have up to three labelled [1maxes [22m-- "x", "y" and "z".
   It is not possible to say where on the graph any particular axis
   will fall because you can change the direction from which the graph
   is seen with [1mset view[22m.

   When discussing data files, the term "record" will be resurrected
   and used to denote a single line of text in the file, that is, the
   characters between newline or end-of-record characters.  A "point"
   is the datum extracted from a single record.  A "datablock" is a set
   of points from consecutive records, delimited by blank records.  A
   line, when referred to in the context of a data file, is a subset of
   a datablock.



   [1m18.  Linetypes, colors, and styles[0m


   Each gnuplot terminal type provides a set of distinct "linetypes".
   These may differ in color, in thickness, in dot/dash pattern, or in
   some combination of color and dot/dash. The default linetypes for a
   particular terminal can be previewed by issuing the [1mtest [22mcommand
   after setting the terminal type.  The pre-defined colors and
   dot/dash patterns are not guaranteed to be consistent for all termi-
   nal types, but all terminals use the special linetype -1 to mean a
   solid line in the primary foreground color (normally black).  Most
   terminals also recognize the special linetype "bgnd" to mean a solid
   line in the background color.

   You can redefine the default linetype properties either interac-
   tively or via an initialization file.  This allows you to customize
   the colors and other properties of the lines used by all gnuplot
   plotting commands.  See [1mset linetype[22m.

   By default, successive functions or datafiles plotted by a single
   command will be assigned successive linetypes.  You can override
   this default sequence by specifying a particular linetype for any
   function, datafile, or plot element.

   Examples:











   GNUPLOT 4.1                                                       30


        plot "foo", "bar"                 # plot two files using line-
   types 1, 2
        plot sin(x) linetype 4            # terminal-specific linetype
   color 4
        plot sin(x) lt -1                 # black

   For many terminal types it is also possible to assign user-defined
   colors using explicit rgb (red, green, blue) values, named colors,
   or color values that refer to the current pm3d palette.

   Examples:

        plot sin(x) lt rgb "violet"       # one of gnuplot's named col-
   ors
        plot sin(x) lt rgb "#FF00FF"      # explicit RGB triple in
   hexadecimal
        plot sin(x) lt palette cb -45     # whatever color corresponds
   to -45
                                          # in the current cbrange of
   the palette
        plot sin(x) lt palette frac 0.3   # fractional value along the
   palette

   See [1mshow colornames[22m, [1mset palette[22m, [1mcbrange[22m.

   For terminals that support dot/dash patterns, each default linetype
   has both a dot-dash pattern and a default color. Gnuplot does not
   currently provide a mechanism for changing the dot-dash pattern, so
   if you want both a particular dash pattern and a particular color
   you must first choose a linetype that has the required dash pattern,
   then override the default color using the keyword [1mlinecolor[22m, abbre-
   viated [1mlc[22m.  For example, the postscript terminal provides a dashed
   blue line as linetype 3.  The plot commands below use this same dash
   pattern for three plots, one in blue (the default), another in red
   (the default for linetype 1), and a third in gold.

   Example:

        set term postscript dashed color
        plot 'foo' lt 3, 'baz' lt 3 linecolor 1, 'bar' lt 3 lc rgb
   'gold'





        [1m18.1.  Colorspec[0m


        Many commands allow you to specify a linetype with an explicit
        color.  Terminal-independent color choice is only possible for
        terminals that support RGB color or pm3d palettes.











   GNUPLOT 4.1                                                       31


        Syntax:

              ... {linecolor | lc} {<colorspec> | <n>}
              ... {textcolor | tc} {<colorspec> | {linetype | lt} <n>}

        where <colorspec> has one of the following forms:

              rgbcolor "colorname"
              rgbcolor "#RRGGBB"
              rgbcolor variable       # color is read from input file
              palette frac <val>      # <val> runs from 0 to 1
              palette cb <value>      # <val> lies within cbrange
              palette z
              variable                # color index is read from input
        file

        The "<n>" is the linetype number the color of which is used,
        see [1mtest[22m.

        "colorname" refers to one of the color names built in to gnu-
        plot. For a list of the available names, see [1mshow colornames[22m.

        "#RRGGBB" is a hexadecimal constant preceded by the "#" symbol.
        The RRGGBB represents the red, green, and blue components of
        the color, each on a scale from 0 - 255.  For example, magenta
        = full-scale red + full-scale blue would be represented by
        #FF00FF, which is the hexadecimal representation of (255 << 16)
        + (0 << 8) + (255).

        The color palette is a linear gradient of colors that smoothly
        maps a single numerical value onto a particular color.  Two
        such mappings are always in effect. [1mpalette frac  [22mmaps a frac-
        tional value between 0 and 1 onto the full range of the color
        palette.  [1mpalette cb [22mmaps the range of the color axis onto the
        same palette.  See [1mset cbrange[22m.  See also [1mset colorbox[22m.  You
        can use either of these to select a constant color from the
        current palette.

        "palette z" maps the z value of each plot segment or plot ele-
        ment into the cbrange mapping of the palette. This allows
        smoothly-varying color along a 3d line or surface. It also
        allows coloring 2D plots by palette values read from an extra
        column of data (not all 2D plot styles allow an extra column).




             [1m18.1.1.  Background color[0m


             Most terminals now allow you to set an explicit background
             color for the plot.  The special linetype [1mbgnd [22mwill draw
             in this color, and [1mbgnd [22mis also recognized as a color.










   GNUPLOT 4.1                                                       32


             Examples:
                  # This will erase a section of the canvas by writing
             over it in the
                  # background color
                  set term wxt background rgb "gray75"
                  set object 1 rectangle from x0,y0 to x1,y1 fillstyle
             solid fillcolor bgnd
                  # This will draw an "invisible" line along the x axis
                  plot 0 lt bgnd



             [1m18.1.2.  Linecolor variable[0m


             [1mlc variable [22mtells the program to use the value read from
             one column of the input data as a linetype index, and use
             the color belonging to that linetype.  This requires a
             corresponding additional column in the [1musing [22mspecifier.
             Text colors can be set similarly using [1mtc variable[22m.

             Examples:
                   # Use the third column of data to assign colors to
             individual points
                   plot 'data' using 1:2:3 with points lc variable

                   # A single data file may contain multiple sets of
             data, separated by two
                   # blank lines.  Each data set is assigned as index
             value (see `index`)
                   # that can be retrieved via the `using` specifier
             `column(-2)`.
                   # See `pseudocolumns`.  This example uses to value
             in column -2 to
                   # draw each data set in a different line color.
                   plot 'data' using 1:2:(column(-2)) with lines lc
             variable




             [1m18.1.3.  Rgbcolor variable[0m


             You can assign a separate color for each data point, line
             segment, or label in your plot.  [1mlc rgbcolor variable[0m
             tells the program to read RGB color information for each
             line in the data file. This requires a corresponding addi-
             tional column in the [1musing [22mspecifier.  The extra column is
             interpreted as a 24-bit packed RGB triple. If the value is
             provided directly in the data file it is easiest to give
             it as a hexidecimal value (see [1mrgbcolor[22m).  Alternatively,
             the [1musing [22mspecifier can contain an expression that










   GNUPLOT 4.1                                                       33


             evaluates to a 24-bit RGB color as in the example below.
             Text colors are similarly set using [1mtc rgbcolor variable[22m.

             Example:
                   # Place colored points in 3D at the x,y,z coordi-
             nates corresponding to
                   # their red, green, and blue components
                   rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
                   splot "data" using 1:2:3:(rgb($1,$2,$3)) with points
             lc rgb variable




        [1m18.2.  Linestyles vs linetypes[0m


        Lines can have additional properties such as linewidth.  You
        can associate these various properties, as well as equivalent
        properties for point symbols, into user-defined "linestyles"
        using the command [1mset style line[22m.  Once you have defined a
        linestyle, you can use it in a plot command to control the
        appearance of one or more plot elements.

        Whereas [1mlinetypes [22mare permanent (they last until you explicitly
        redefine them), [1mlinestyles [22mare temporary.  They only last until
        the next reset of the graphics state.

        Examples:

             # define a new line style with terminal-independent color
        cyan,
             # linewidth 3, and associated point type 6 (a circle with
        a dot in it).
             set style line 5 lt rgb "cyan" lw 3 pt 6
             plot sin(x) with linespoints ls 5          # user-defined
        line style 5




   [1m19.  Mouse input[0m


   Many terminals allow interaction with the current plot using the
   mouse. Some also support the definition of hotkeys to activate pre-
   defined functions by hitting a single key while the mouse focus is
   in the active plot window.  It is even possible to combine mouse
   input with [1mbatch [22mcommand scripts, by invoking the command [1mpause[0m
   [1mmouse [22mand then using the mouse variables returned by mouse clicking
   as parameters for subsequent scripted actions.  See [1mbind [22mand [1mmouse[0m
   [1mvariables[22m.  See also the command [1mset mouse[22m.











   GNUPLOT 4.1                                                       34


        [1m19.1.  Bind[0m


        Syntax:
              bind {allwindows} [<key-sequence>] ["<gnuplot commands>"]
              bind <key-sequence> ""
              reset bind

        The [1mbind [22mallows defining or redefining a hotkey, i.e. a
        sequence of gnuplot commands which will be executed when a cer-
        tain key or key sequence is pressed while the driver's window
        has the input focus. Note that [1mbind [22mis only available if gnu-
        plot was compiled with [1mmouse [22msupport and it is used by all
        mouse-capable terminals. A user-specified binding supersedes
        any builtin bindings, except that <space> and 'q' cannot nor-
        mally be rebound. For an exception, see [1mbind space[22m.

        Only mouse button 1 can be bound, and only for 2D plots.

        You get the list of all hotkeys by typing [1mshow bind [22mor [1mbind [22mor
        by typing the hotkey 'h' in the graph window.

        Key bindings are restored to their default state by [1mreset bind[22m.

        Note that multikey-bindings with modifiers must be given in
        quotes.

        Normally hotkeys are only recognized when the currently active
        plot window has focus. [1mbind allwindows <key> ... [22m(short form:
        [1mbind all <key> ...[22m)  causes the binding for <key> to apply to
        all gnuplot plot windows, active or not.  In this case gnuplot
        variable MOUSE_KEY_WINDOW is set to the ID of the originating
        window, and may be used by the bound command.

        Examples:

        - set bindings:

            bind a "replot"
            bind "ctrl-a" "plot x*x"
            bind "ctrl-alt-a" 'print "great"'
            bind Home "set view 60,30; replot"
            bind all Home 'print "This is window ",MOUSE_KEY_WINDOW'

        - show bindings:
            bind "ctrl-a"          # shows the binding for ctrl-a
            bind                   # shows all bindings
            show bind              # show all bindings

        - remove bindings:
            bind "ctrl-alt-a" ""   # removes binding for ctrl-alt-a
                                     (note that builtins cannot be
        removed)










   GNUPLOT 4.1                                                       35


            reset bind             # installs default (builtin) bind-
        ings
            bind!                  # deprecated form of "reset bind"

        - bind a key to toggle something:
          v=0
          bind "ctrl-r" "v=v+1;if(v%2)set term x11 noraise; else set
        term x11 raise"

        Modifiers (ctrl / alt) are case insensitive, keys not:
            ctrl-alt-a == CtRl-alT-a
            ctrl-alt-a != ctrl-alt-A

        List of modifiers (alt == meta):
            ctrl, alt

        List of supported special keys:

           "BackSpace", "Tab", "Linefeed", "Clear", "Return", "Pause",
        "Scroll_Lock",
           "Sys_Req", "Escape", "Delete", "Home", "Left", "Up",
        "Right", "Down",
           "PageUp", "PageDown", "End", "Begin",

           "KP_Space", "KP_Tab", "KP_Enter", "KP_F1", "KP_F2", "KP_F3",
        "KP_F4",
           "KP_Home", "KP_Left", "KP_Up", "KP_Right", "KP_Down",
        "KP_PageUp",
           "KP_PageDown", "KP_End", "KP_Begin", "KP_Insert",
        "KP_Delete", "KP_Equal",
           "KP_Multiply", "KP_Add", "KP_Separator", "KP_Subtract",
        "KP_Decimal",
           "KP_Divide",

           "KP_1" - "KP_9", "F1" - "F12"

        The following are window events rather than actual keys

           "Button1" "Close"

        See also help for [1mmouse[22m.




             [1m19.1.1.  Bind space[0m


             If gnuplot was built with configuration option --enable-
             raise-console, then typing <space> in the plot window
             raises gnuplot's command window. This hotkey can be
             changed to ctrl-space by starting gnuplot as 'gnuplot
             -ctrlq', or by setting the XResource 'gnuplot*ctrlq'.  See










   GNUPLOT 4.1                                                       36


             [1mx11 command-line-options[22m.



        [1m19.2.  Mouse variables[0m


        When [1mmousing [22mis active, clicking in the active window will set
        several user variables that can be accessed from the gnuplot
        command line. The coordinates of the mouse at the time of the
        click are stored in MOUSE_X MOUSE_Y MOUSE_X2 and MOUSE_Y2. The
        mouse button clicked, and any meta-keys active at that time,
        are stored in MOUSE_BUTTON MOUSE_SHIFT MOUSE_ALT and
        MOUSE_CTRL.  These variables are set to undefined at the start
        of every plot, and only become defined in the event of a mouse
        click in the active plot window. To determine from a script if
        the mouse has been clicked in the active plot window, it is
        sufficient to test for any one of these variables being
        defined.

              plot 'something'
              pause mouse
              if (defined(MOUSE_BUTTON)) call 'something_else'; \
              else print "No mouse click."

        It is also possible to track keystrokes in the plot window
        using the mousing code.

              plot 'something'
              pause mouse keypress
              print "Keystroke ", MOUSE_KEY, " at ", MOUSE_X, " ",
        MOUSE_Y

        When [1mpause mouse keypress [22mis terminated by a keypress, then
        MOUSE_KEY will contain the ascii character value of the key
        that was pressed. MOUSE_CHAR will contain the character itself
        as a string variable.  If the pause command is terminated
        abnormally (e.g. by ctrl-C or by externally closing the plot
        window) then MOUSE_KEY will equal -1.

        Note that after a zoom by mouse, you can read the new ranges as
        GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN, and GPVAL_Y_MAX, see
        [1mgnuplot-defined variables[22m.





   [1m20.  Plotting[0m


   There are three [1mgnuplot [22mcommands which actually create a plot: [1mplot[22m,
   [1msplot [22mand [1mreplot[22m.  [1mplot [22mgenerates 2D plots, [1msplot [22mgenerates 3D plots










   GNUPLOT 4.1                                                       37


   (actually 2D projections, of course), and [1mreplot [22mappends its argu-
   ments to the previous [1mplot [22mor [1msplot [22mand executes the modified com-
   mand.

   Much of the general information about plotting can be found in the
   discussion of [1mplot[22m; information specific to 3D can be found in the
   [1msplot [22msection.

   [1mplot [22moperates in either rectangular or polar coordinates -- see [1mset[0m
   [1mpolar [22mfor details of the latter.  [1msplot [22moperates only in rectangular
   coordinates, but the [1mset mapping [22mcommand allows for a few other
   coordinate systems to be treated.  In addition, the [1musing [22moption
   allows both [1mplot [22mand [1msplot [22mto treat almost any coordinate system
   you'd care to define.

   [1mplot [22malso lets you use each of the four borders -- x (bottom), x2
   (top), y (left) and y2 (right) -- as an independent axis.  The [1maxes[0m
   option lets you choose which pair of axes a given function or data
   set is plotted against.  A full complement of [1mset [22mcommands exists to
   give you complete control over the scales and labelling of each
   axis.  Some commands have the name of an axis built into their
   names, such as [1mset xlabel[22m.  Other commands have one or more axis
   names as options, such as [1mset logscale xy[22m.  Commands and options
   controlling the z axis have no effect on 2D graphs.

   [1msplot [22mcan plot surfaces and contours in addition to points and/or
   lines.  See [1mset isosamples [22mfor information about defining the grid
   for a 3D function.  See [1msplot datafile [22mfor information about the
   requisite file structure for 3D data values, [1mset contour [22mand [1mset[0m
   [1mcntrparam [22mfor information about contours.

   In [1msplot[22m, control over the scales and labels of the axes are the
   same as with [1mplot[22m, except that commands and options controlling the
   x2 and y2 axes have no effect whereas of course those controlling
   the z axis do take effect.



   [1m21.  Start-up (initialization)[0m


   When gnuplot is run, it first looks for a system-wide initialization
   file named [1mgnuplotrc[22m.  The location of this file is determined when
   the program is built and is reported by [1mshow loadpath[22m.  The program
   then looks in the user's HOME directory for a file called [1m.gnuplot[0m
   on Unix-like systems or [1mGNUPLOT.INI [22mon other systems.  (Windows and
   OS/2 will look for it in the directory named in the environment
   variable [1mGNUPLOT[22m; Windows will use [1mUSERPROFILE [22mif GNUPLOT is not
   defined).  Note: The program can be configured to look first in the
   current directory, but this is not recommended because it is bad
   security practice.












   GNUPLOT 4.1                                                       38


   [1m22.  String constants and string variables[0m


   In addition to string constants, most gnuplot commands also accept a
   string variable, a string expression, or a function that returns a
   string.  For example, the following four methods of creating a plot
   all result in the same plot title:

         four = "4"
         graph4 = "Title for plot #4"
         graph(n) = sprintf("Title for plot #%d",n)

         plot 'data.4' title "Title for plot #4"
         plot 'data.4' title graph4
         plot 'data.4' title "Title for plot #".four
         plot 'data.4' title graph(4)

   Since integers are promoted to strings when operated on by the
   string concatenation operator, the following method also works:

         N = 4
         plot 'data.'.N title "Title for plot #".N

   In general, elements on the command line will only be evaluated as
   possible string variables if they are not otherwise recognizable as
   part of the normal gnuplot syntax. So the following sequence of com-
   mands is legal, although probably should be avoided so as not to
   cause confusion:

         plot = "my_datafile.dat"
         title = "My Title"
         plot plot title title

   There are three binary operators that require string operands: the
   string concatenation operator ".", the string equality operator "eq"
   and the string inequality operator "ne".  The following example will
   print TRUE.

        if ("A"."B" eq "AB") print "TRUE"

   See also the two string formatting functions [1mgprintf [22mand [1msprintf[22m.

   Substrings can be specified by appending a range specifier to any
   string, string variable, or string-valued function.  The range spec-
   ifier has the form [begin:end], where begin is the index of the
   first character of the substring and end is the index of the last
   character of the substring.  The first character has index 1.  The
   begin or end fields may be empty, or contain '*', to indicate the
   true start or end of the original string.  E.g.  str[:] and str[*:*]
   both describe the full string str.













   GNUPLOT 4.1                                                       39


   [1m23.  Substitution and Command line macros[0m


   When a command line to gnuplot is first read, i.e. before it is
   interpreted or executed, two forms of lexical substitution are per-
   formed. These are triggered by the presence of text in backquotes
   (ascii character 96) or preceded by @ (ascii character 64).




        [1m23.1.  Substitution of system commands in backquotes[0m


        Command-line substitution is specified by a system command
        enclosed in backquotes.  This command is spawned and the output
        it produces replaces the backquoted text on the command line.
        Some implementations also support pipes;  see [1mplot datafile[0m
        [1mspecial-filenames[22m.

        Command-line substitution can be used anywhere on the [1mgnuplot[0m
        command line, except inside strings delimited by single quotes.

        Example:

        This will run the program [1mleastsq [22mand replace [1mleastsq [22m(includ-
        ing backquotes) on the command line with its output:
              f(x) = `leastsq`

        or, in VMS
              f(x) = `run leastsq`

        These will generate labels with the current time and userid:
              set label "generated on `date +%Y-%m-%d` by `whoami`" at
        1,1
              set timestamp "generated on %Y-%m-%d by `whoami`"



        [1m23.2.  Substitution of string variables as macros[0m


        Substitution of command line macros is disabled by default, but
        may be enabled using the [1mset macros [22mcommand.  If macro substi-
        tution is enabled, the character @ is used to trigger substitu-
        tion of the current value of a string variable into the command
        line. The text in the string variable may contain any number of
        lexical elements.  This allows string variables to be used as
        command line macros.  Only string constants may be expanded
        using this mechanism, not string-valued expressions.  For exam-
        ple:

              set macros










   GNUPLOT 4.1                                                       40


              style1 = "lines lt 4 lw 2"
              style2 = "points lt 3 pt 5 ps 2"
              range1 = "using 1:3"
              range2 = "using 1:5"
              plot "foo" @range1 with @style1, "bar" @range2 with
        @style2

        The line containing @ symbols is expanded on input, so that by
        the time it is executed the effect is identical to having typed
        in full

              plot "foo" using 1:3 with lines lt 4 lw 2, \
                   "bar" using 1:5 with points lt 3 pt 5 ps 2

        The function exists() may be useful in connection with macro
        evaluation.  The following example checks that C can safely be
        expanded as the name of a user-defined variable:

              C = "pi"
              if (exists(C)) print C," = ", @C

        Macro expansion does not occur inside either single or double
        quotes.  However macro expansion does occur inside backquotes.

        Macro expansion is handled as the very first thing the inter-
        preter does when looking at a new line of commands and is only
        done once. Therefore, code like the following will execute cor-
        rectly:

             A = "c=1"
             @A

        but this line will not, since the macro is defined on the same
        line and will not be expanded in time

             A = "c=1"; @A   # will not expand to c=1

        For execution of complete commands the [1mevaluate [22mcommand may
        also be handy.



        [1m23.3.  String variables, macros, and command line substitution[0m


        The interaction of string variables, backquotes and macro sub-
        stitution is somewhat complicated.  Backquotes do not block
        macro substitution, so

              filename = "mydata.inp"
              lines = ` wc --lines @filename | sed "s/ .*//" `

        results in the number of lines in mydata.inp being stored in










   GNUPLOT 4.1                                                       41


        the integer variable lines. And double quotes do not block
        backquote substitution, so

              mycomputer = "`uname -n`"

        results in the string returned by the system command [1muname -n[0m
        being stored in the string variable mycomputer.

        However, macro substitution is not performed inside double
        quotes, so you cannot define a system command as a macro and
        then use both macro and backquote substitution at the same
        time.

               machine_id = "uname -n"
               mycomputer = "`@machine_id`"  # doesn't work!!

        This fails because the double quotes prevent @machine_id from
        being interpreted as a macro. To store a system command as a
        macro and execute it later you must instead include the back-
        quotes as part of the macro itself.  This is accomplished by
        defining the macro as shown below.  Notice that the sprintf
        format nests all three types of quotes.

              machine_id = sprintf('"`uname -n`"')
              mycomputer = @machine_id



   [1m24.  Syntax[0m


   Options and any accompanying parameters are separated by spaces
   whereas lists and coordinates are separated by commas.  Ranges are
   separated by colons and enclosed in brackets [], text and file names
   are enclosed in quotes, and a few miscellaneous things are enclosed
   in parentheses.

   Commas are used to separate coordinates on the [1mset [22mcommands [1marrow[22m,
   [1mkey[22m, and [1mlabel[22m; the list of variables being fitted (the list after
   the [1mvia [22mkeyword on the [1mfit [22mcommand); lists of discrete contours or
   the loop parameters which specify them on the [1mset cntrparam [22mcommand;
   the arguments of the [1mset [22mcommands [1mdgrid3d[22m, [1mdummy[22m, [1misosamples[22m, [1moff-[0m
   [1msets[22m, [1morigin[22m, [1msamples[22m, [1msize[22m, [1mtime[22m, and [1mview[22m; lists of tics or the
   loop parameters which specify them; the offsets for titles and axis
   labels; parametric functions to be used to calculate the x, y, and z
   coordinates on the [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands; and the complete
   sets of keywords specifying individual plots (data sets or func-
   tions) on the [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands.

   Parentheses are used to delimit sets of explicit tics (as opposed to
   loop parameters) and to indicate computations in the [1musing [22mfilter of
   the [1mfit[22m, [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands.











   GNUPLOT 4.1                                                       42


   (Parentheses and commas are also used as usual in function nota-
   tion.)

   Square brackets are used to delimit ranges given in [1mset[22m, [1mplot [22mor
   [1msplot [22mcommands.

   Colons are used to separate extrema in [1mrange [22mspecifications (whether
   they are given on [1mset[22m, [1mplot [22mor [1msplot [22mcommands) and to separate
   entries in the [1musing [22mfilter of the [1mplot[22m, [1mreplot[22m, [1msplot [22mand [1mfit [22mcom-
   mands.

   Semicolons are used to separate commands given on a single command
   line.

   Curly braces are used in the syntax for enhanced text mode and to
   delimit blocks in if/then/else statements.  They are also used to
   denote complex numbers: {3,2} = 3 + 2i.

   The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline
   to be specified by \\ in a single-quoted string or \\\\ in a double-
   quoted string.




        [1m24.1.  Quote Marks[0m


        Gnuplot uses three forms of quote marks for delimiting text
        strings, double-quote (ascii 34), single-quote (ascii 39), and
        backquote (ascii 96).

        Filenames may be entered with either single- or double-quotes.
        In this manual the command examples generally single-quote
        filenames and double-quote other string tokens for clarity.

        String constants and text strings used for labels, titles, or
        other plot elements may be enclosed in either single quotes or
        double quotes. Further processing of the quoted text depends on
        the choice of quote marks.

        Backslash processing of special characters like \n (newline)
        and \345 (octal character code) is performed for double-quoted
        strings.  In single-quoted strings, backslashes are just ordi-
        nary characters.  To get a single-quote (ascii 39) in a single-
        quoted string, it has to be doubled.  Thus the strings "d\" s'
        b\\" and 'd" s'' b\' are completely equivalent.

        Text justification is the same for each line of a multi-line
        string.  Thus the center-justified string
              "This is the first line of text.\nThis is the second
        line."
        will produce










   GNUPLOT 4.1                                                       43


                               This is the first line of text.
                                  This is the second line.
        but
              'This is the first line of text.\nThis is the second
        line.'
        will produce
                  This is the first line of text.\nThis is the second
        line.

        Enhanced text processing is performed for both double-quoted
        text and single-quoted text, but only by terminals supporting
        this mode.  See [1menhanced text[22m.

        Back-quotes are used to enclose system commands for substitu-
        tion into the command line.  See [1msubstitution[22m.



   [1m25.  Time/Date data[0m


   [1mgnuplot [22msupports the use of time and/or date information as input
   data.  This feature is activated by the commands [1mset xdata time[22m, [1mset[0m
   [1mydata time[22m, etc.

   Internally all times and dates are converted to the number of sec-
   onds from the year 2000.  The command [1mset timefmt [22mdefines the format
   for all inputs: data files, ranges, tics, label positions---in
   short, anything that accepts a data value must receive it in this
   format.  Since only one input format can be in force at a given
   time, all time/date quantities being input at the same time must be
   presented in the same format.  Thus if both x and y data in a file
   are time/date, they must be in the same format.

   The conversion to and from seconds assumes Universal Time (which is
   the same as Greenwich Standard Time).  There is no provision for
   changing the time zone or for daylight savings.  If all your data
   refer to the same time zone (and are all either daylight or stan-
   dard) you don't need to worry about these things.  But if the abso-
   lute time is crucial for your application, you'll need to convert to
   UT yourself.

   Commands like [1mshow xrange [22mwill re-interpret the integer according to
   [1mtimefmt[22m.  If you change [1mtimefmt[22m, and then [1mshow [22mthe quantity again,
   it will be displayed in the new [1mtimefmt[22m.  For that matter, if you
   give the deactivation command (like [1mset xdata[22m), the quantity will be
   shown in its numerical form.

   The commands [1mset format [22mor [1mset tics format [22mdefine the format that
   will be used for tic labels, whether or not the specified axis is
   time/date.

   If time/date information is to be plotted from a file, the [1musing[0m










   GNUPLOT 4.1                                                       44


   option _must_ be used on the [1mplot [22mor [1msplot [22mcommand.  These commands
   simply use white space to separate columns, but white space may be
   embedded within the time/date string.  If you use tabs as a separa-
   tor, some trial-and-error may be necessary to discover how your sys-
   tem treats them.

   The [1mtime [22mfunction can be used to get the current system time. This
   value can be converted to a date string with the [1mstrftime [22mfunction,
   or it can be used in conjunction with [1mtimecolumn [22mto generate rela-
   tive time/date plots.  The type of the argument determines what is
   returned. If the argument is an integer, [1mtime [22mreturns the current
   time as an integer, in seconds from 1 Jan 2000. If the argument is
   real (or complex), the result is real as well.  The precision of the
   fractional (sub-second) part depends on your operating system. If
   the argument is a string, it is assumed to be a format string, and
   it is passed to [1mstrftime [22mto provide a formatted time/date string.

   The following example demonstrates time/date plotting.

   Suppose the file "data" contains records like

         03/21/95 10:00  6.02e23

   This file can be plotted by

         set xdata time
         set timefmt "%m/%d/%y"
         set xrange ["03/21/95":"03/22/95"]
         set format x "%m/%d"
         set timefmt "%m/%d/%y %H:%M"
         plot "data" using 1:3

   which will produce xtic labels that look like "03/21".

   See [1mtime_specifiers[22m.




   [1m26.  Plotting styles[0m



   There are many plotting styles available in gnuplot.  They are
   listed alphabetically below.  The commands [1mset style data [22mand [1mset[0m
   [1mstyle function [22mchange the default plotting style for subsequent [1mplot[0m
   and [1msplot [22mcommands.

   You also have the option to specify the plot style explicitly as
   part of the [1mplot [22mor [1msplot [22mcommand.  If you want to mix plot styles
   within a single plot, you must specify the plot style for each com-
   ponent.











   GNUPLOT 4.1                                                       45


   Example:

        plot 'data' with boxes, sin(x) with lines

   Each plot style has its own expected set of data entries in a data
   file.  For example by default the [1mlines [22mstyle expects either a sin-
   gle column of y values (with implicit x ordering) or a pair of col-
   umns with x in the first and y in the second.  For more information
   on how to fine-tune how columns in a file are interpreted as plot
   data, see [1musing[22m.




   [1m27.  Boxerrorbars[0m


   The [1mboxerrorbars [22mstyle is only relevant to 2D data plotting.  It is
   a combination of the [1mboxes [22mand [1myerrorbars [22mstyles.  It uses 3, 4, or
   5 columns of data:

        3 columns:  x  y  ydelta
        4 columns:  x  y  ydelta xdelta        # boxwidth != -2
        4 columns:  x  y  ylow  yhigh          # boxwidth == -2
        5 columns:  x  y  ylow  yhigh  xdelta

   The boxwidth will come from the fourth column if the y errors are
   given as "ydelta" and the boxwidth was not previously set to -2.0
   ([1mset boxwidth -2.0[22m) or from the fifth column if the y errors are in
   the form of "ylow yhigh".  The special case  [1mboxwidth = -2.0 [22mis for
   four-column data with y errors in the form "ylow yhigh".  In this
   case the boxwidth will be calculated so that each box touches the
   adjacent boxes.  The width will also be calculated in cases where
   three-column data are used.

   An additional (4th, 5th or 6th) input column may be used to provide
   variable (per-datapoint) color information (see [1mlinecolor [22mand [1mrgb-[0m
   [1mcolor variable[22m).  The error bar will be drawn in the same color as
   the border of the box.

   The box height is determined from the y error in the same way as it
   is for the [1myerrorbars [22mstyle---either from y-ydelta to y+ydelta or
   from ylow to yhigh, depending on how many data columns are provided.
   See also errorbar demo.



   [1m28.  Boxes[0m


   The [1mboxes [22mstyle is only relevant to 2D plotting.  It draws a box
   centered about the given x coordinate that extends from the x axis
   (not from the graph border) to the given y coordinate.  It uses 2 or










   GNUPLOT 4.1                                                       46


   3 columns of basic data.  Additional input columns may be used to
   provide information such as variable line or fill color (see [1mrgb-[0m
   [1mcolor variable[22m).

        2 columns:  x  y
        3 columns:  x  y  x_width

   The width of the box is obtained in one of three ways.  If the input
   data has a third column, this will be used to set the width of the
   box.  If not, if a width has been set using the [1mset boxwidth [22mcom-
   mand, this will be used.  If neither of these is available, the
   width of each box will be calculated automatically so that it
   touches the adjacent boxes.

   The interior of the boxes is drawn according to the current fill-
   style.  See [1mset style fill [22mfor details.  Alternatively a new fill-
   style may be specified in the plot command.

   For fillstyle [1mempty [22mthe box is not filled.

   For fillstyle [1msolid [22mthe box is filled with a solid rectangle of the
   current drawing color. There is an optional parameter <density> that
   controls the fill density; it runs from 0 (background color) to 1
   (current drawing color).

   For fillstyle [1mpattern [22mthe box is filled in the current drawing color
   with a pattern, if supported by the terminal driver.

   Examples:

   To plot a data file with solid filled boxes with a small vertical
   space separating them (bargraph):

         set boxwidth 0.9 relative
         set style fill solid 1.0
         plot 'file.dat' with boxes

   To plot a sine and a cosine curve in pattern-filled boxes style:

         set style fill pattern
         plot sin(x) with boxes, cos(x) with boxes

   The sin plot will use pattern 0; the cos plot will use pattern 1.
   Any additional plots would cycle through the patterns supported by
   the terminal driver.

   To specify explicit fillstyles for each dataset:

        plot 'file1' with boxes fs solid 0.25, \
             'file2' with boxes fs solid 0.50, \
             'file3' with boxes fs solid 0.75, \
             'file4' with boxes fill pattern 1, \
             'file5' with boxes fill empty










   GNUPLOT 4.1                                                       47


   [1m29.  Boxplot[0m


   Boxplots are a common way to represent a statistical distribution of
   values.  Quartile boundaries are determined such that 1/4 of the
   points have a value equal or less than the first quartile boundary,
   1/2 of the points have a value equal or less than the second quar-
   tile (median) value, etc.  A box is drawn around the region between
   the first and third quartiles, with a horizontal line at the median
   value.  Whiskers extend from the box to user-specified limits.
   Points that lie outside these limits are drawn individually.

   Examples

       # Place a boxplot at x coordinate 1.0 representing the y values
   in column 5
       plot 'data' using (1.0):5

       # Same plot but suppress outliers and force the width of the
   boxplot to 0.3
       set style boxplot nooutliers
       plot 'data' using (1.0):5:(0.3)

   By default only one boxplot is produced that represents all y values
   from the second column of the using specification. However, an addi-
   tional (fourth) colunm can be added to the specification. If
   present, the values of that column will be interpreted as the dis-
   crete levels of a factor variable.  As many boxplots will be drawn
   as there are levels in the factor variable.  The separation between
   these boxplots is 1.0 by default, but it can be changed by [1mset style[0m
   [1mboxplot separation[22m. By default, the value of the factor variable is
   shown as a tic label below (or above) each boxplot.

   Example

       # Suppose that column 2 of 'data' contains either "control" or
   "treatment"
       # The following example produces two boxplots, one for each
   level of the
       # factor
       plot 'data' using (1.0):5:(0):2

   The default width of the box can be set via [1mset boxwidth <width> [22mor
   may be specified as an optional 3rd column in the [1musing [22mclause of
   the plot command.  The first and third columns (x coordinate and
   width) are normally provided as constants rather than as data col-
   umns.

   By default the whiskers extend from the ends of the box to the most
   distant point whose y value lies within 1.5 times the interquartile
   range. By default outliers are drawn as circles (point type 7).  The
   width of the bars at the end of the whiskers may be controlled using
   [1mset bars[22m.










   GNUPLOT 4.1                                                       48


   These default properties may be changed using the [1mset style boxplot[0m
   command.  See [1mset style boxplot[22m, [1mbars[22m, [1mboxwidth[22m, [1mfillstyle[22m, [1mcandle-[0m
   [1msticks[22m.




   [1m30.  Boxxyerrorbars[0m


   The [1mboxxyerrorbars [22mstyle is only relevant to 2D data plotting.  It
   is similar to the [1mxyerrorbars [22mstyle except that it draws rectangular
   areas rather than simple crosses.  It uses either 4 or 6 basic col-
   umns of input data.  Additional input columns may be used to provide
   information such as variable line or fill color (see [1mrgbcolor vari-[0m
   [1mable[22m).

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   The box width and height are determined from the x and y errors in
   the same way as they are for the [1mxyerrorbars [22mstyle---either from
   xlow to xhigh and from ylow to yhigh, or from x-xdelta to x+xdelta
   and from y-ydelta to y+ydelta, depending on how many data columns
   are provided.

   An additional (5th or 7th) input column may be used to provide vari-
   able (per-datapoint) color information (see [1mlinecolor [22mand [1mrgbcolor[0m
   [1mvariable[22m).

   The interior of the boxes is drawn according to the current fill-
   style.  See [1mset style fill [22mand [1mboxes [22mfor details.  Alternatively a
   new fillstyle may be specified in the plot command.



   [1m31.  Candlesticks[0m


   The [1mcandlesticks [22mstyle can be used for 2D data plotting of financial
   data or for generating box-and-whisker plots of statistical data.
   The symbol is a rectangular box, centered horizontally at the x
   coordinate and limited vertically by the opening and closing prices.
   A vertical line segment at the x coordinate extends up from the top
   of the rectangle to the high price and another down to the low.  The
   vertical line will be unchanged if the low and high prices are
   interchanged.

   Five columns of basic data are required:

         financial data:   date  open  low  high  close
         whisker plot:     x  box_min  whisker_min  whisker_high
   box_high










   GNUPLOT 4.1                                                       49


   The width of the rectangle can be controlled by the [1mset boxwidth[0m
   command.  For backwards compatibility with earlier gnuplot versions,
   when the boxwidth parameter has not been set then the width of the
   candlestick rectangle is controlled by [1mset bars <width>[22m.

   Alternatively, an explicit width for each box-and-whiskers grouping
   may be specified in an optional 6th column of data.  The width must
   be given in the same units as the x coordinate.

   An additional (6th, or 7th if the 6th column is used for width data)
   input column may be used to provide variable (per-datapoint) color
   information (see [1mlinecolor [22mand [1mrgbcolor variable[22m).

   By default the vertical line segments have no crossbars at the top
   and bottom. If you want crossbars, which are typically used for box-
   and-whisker plots, then add the keyword [1mwhiskerbars [22mto the plot com-
   mand.  By default these whiskerbars extend the full horizontal width
   of the candlestick, but you can modify this by specifying a fraction
   of the full width.

   The usual convention for financial data is that the rectangle is
   empty if (open < close) and solid fill if (close < open). This is
   the behavior you will get if the current fillstyle is set to
   "empty". See [1mfillstyle[22m.  If you set the fillstyle to solid or pat-
   tern, then this will be used for all boxes independent of open and
   close values.  See also [1mset bars [22mand [1mfinancebars[22m.  See also the can-
   dlestick and finance demos.

   Note: To place additional symbols, such as the median value, on a
   box-and-whisker plot requires additional plot commands as in this
   example:

     # Data columns:X Min 1stQuartile Median 3rdQuartile Max
     set bars 4.0
     set style fill empty
     plot 'stat.dat' using 1:3:2:6:5 with candlesticks title 'Quar-
   tiles', \
          ''         using 1:4:4:4:4 with candlesticks lt -1 notitle

     # Plot with crossbars on the whiskers, crossbars are 50% of full
   width
     plot 'stat.dat' using 1:3:2:6:5 with candlesticks whiskerbars 0.5

   See [1mset boxwidth[22m, [1mset bars[22m, [1mset style fill[22m, and [1mboxplot[22m.



   [1m32.  Circles[0m


   The [1mcircles [22mstyle plots a circle with an explicit radius at each
   data point.  If three columns of data are present, they are inter-
   preted as x, y, radius.  The radius is always interpreted in the










   GNUPLOT 4.1                                                       50


   units of the plot's horizontal axis (x or x2).  The scale on y and
   the aspect ratio of the plot are both ignored.  If only two columns
   are present, the radius is taken from [1mset style circle[22m.  In this
   case the radius may be given in graph or screen coordinates.  By
   default a full circle will be drawn.  It is possible to plot arc
   segments instead of full circles by specifying a start and end angle
   in the 4th and 5th columns.  An optional 4th or 6th column can spec-
   ify per-circle color.  The start and end angles of the circle seg-
   ments must be specified in degrees.


   Examples:

       # draws circles whose area is proportional to the value in col-
   umn 3
       set style fill transparent solid 0.2 noborder
       plot 'data' using 1:2:(sqrt($3)) with circles, \
            'data' using 1:2 with linespoints

       # draws Pac-men instead of circles
       plot 'data' using 1:2:(10):(40):(320) with circles

       # draw a pie chart with inline data
       set xrange [-15:15]
       set style fill transparent solid 0.9 noborder
       plot '-' using 1:2:3:4:5:6 with circles lc var
       0    0    5    0    30    1
       0    0    5   30    70    2
       0    0    5   70   120    3
       0    0    5  120   230    4
       0    0    5  230   360    5
       e

   The result is similar to using a [1mpoints [22mplot with variable size
   points and pointstyle 7, except that the circles will scale with the
   x axis range.  See also [1mset object circle [22mand [1mfillstyle[22m.



   [1m33.  Ellipses[0m


   The [1mellipses [22mstyle plots an ellipse at each data point.  This style
   is only relevant for 2D plotting.  Each ellipse is described in
   terms of its center, major and minor diameters, and the angle
   between its major diameter and the x axis.

        2 columns: x y
        3 columns: x y major_diam
        4 columns: x y major_diam minor_diam
        5 columns: x y major_diam minor_diam angle

   If only two input columns are present, they are taken as the










   GNUPLOT 4.1                                                       51


   coordinates of the centers, and the ellipses will be drawn with the
   default extent (see [1mset style ellipse[22m).  The orientation of the
   ellipse, which is defined as the angle between the major diameter
   and the plot's x axis, is taken from the default ellipse style (see
   [1mset style ellipse[22m).  If three input columns are provided, the third
   column is used for both diameters.  The orientation angle defaults
   to zero.  If four columns are present, they are interpreted as x, y,
   major diameter, minor diameter.  Note that these are diameters, not
   radii.  An optional 5th column may be used to specify the orienta-
   tion angle in degrees.  The ellipses will also be drawn with their
   default extent if either of the supplied diameters in the 3-4-5 col-
   umn form is negative.

   In all of the above cases, optional variable color data may be given
   in an additional last (3th, 4th, 5th or 6th) column. See [1mcolorspec[0m
   for further information.

   By default, the major diameter is interpreted in the units of the
   plot's horizontal axis (x or x2) while the minor diameter in that of
   the vertical (y or y2).  This implies that if the x and y axis
   scales are not equal, then the major/minor diameter ratio will no
   longer be correct after rotation.  This behavior can be changed with
   the [1munits [22mkeyword, however.

   There are three alternatives: if [1munits xy [22mis included in the plot
   specification, the axes will be scaled as described above. [1munits xx[0m
   ensures that both diameters are interpreted in units of the x axis,
   while [1munits yy [22mmeans that both diameters are interpreted in units of
   the y axis. In the latter two cases the ellipses will have the cor-
   rect aspect ratio, even if the plot is resized.

   If [1munits [22mis omitted, the default setting will be used, which is
   equivalent to [1munits xy[22m. This can be redefined by [1mset style ellipse[22m.

   Example (draws ellipses, cycling through the available line types):

       plot 'data' using 1:2:3:4:(0):0 with ellipses

   See also [1mset object ellipse[22m, [1mset style ellipse [22mand [1mfillstyle[22m.



   [1m34.  Dots[0m


   The [1mdots [22mstyle plots a tiny dot at each point; this is useful for
   scatter plots with many points.  Either 1 or 2 columns of input data
   are required in 2D.  Three columns are required in 3D.

   For some terminals (post, pdf) the size of the dot can be controlled
   by changing the linewidth.

        1 column    y         # x is row number










   GNUPLOT 4.1                                                       52


        2 columns:  x  y
        3 columns:  x  y  z   # 3D only (splot)




   [1m35.  Filledcurves[0m


   The [1mfilledcurves [22mstyle is only relevant to 2D plotting. Three vari-
   ants are possible. The first two variants require either a function
   or two columns of input data, and may be further modified by the
   options listed below.

   Syntax:

       plot ... with filledcurves [option]

   where the option can be one of the following

       [closed | {above | below}
       {x1 | x2 | y1 | y2 | r}[=<a>] | xy=<x>,<y>]

   The first variant, [1mclosed[22m, treats the curve itself as a closed poly-
   gon.  This is the default if there are two columns of input data.

   The second variant is to fill the area between the curve and a given
   axis, a horizontal or vertical line, or a point.

       filledcurves closed   ... just filled closed curve,
       filledcurves x1       ... x1 axis,
       filledcurves x2       ... x2 axis, etc for y1 and y2 axes,
       filledcurves y1=0     ... line y=0 (at y1 axis) ie parallel to
   x1 axis,
       filledcurves y2=42    ... line y=42 (at y2 axis) ie parallel to
   x2, etc,
       filledcurves xy=10,20 ... point 10,20 of x1,y1 axes (arc-like
   shape).
       filledcurves above r=1.5  the area of a polar plot outside
   radius 1.5

   The third variant requires three columns of input data: the x coor-
   dinate and two y coordinates corresponding to two curves sampled at
   the same set of x coordinates; the area between the two curves is
   filled.  This is the default if there are three or more columns of
   input data.

        3 columns:  x  y1  y2

   Example of filling the area between two input curves.  fill between
   curves demo.

       plot 'data' using 1:2:3 with filledcurves










   GNUPLOT 4.1                                                       53


   The [1mabove [22mand [1mbelow [22moptions apply both to commands of the form
       ... filledcurves above {x1|x2|y1|y2|r}=<val>
   and to commands of the form
       ... using 1:2:3 with filledcurves below
   In either case the option limits the filled area to one side of the
   bounding line or curve.

   Note: Not all terminal types support this plotting mode.

   Zooming a filled curve drawn from a datafile may produce empty or
   incorrect areas because gnuplot is clipping points and lines, and
   not areas.

   If the values of <a>, <x>, <y> are out of the drawing boundary, then
   they are moved to the graph boundary. Then the actually filled area
   in the case of option xy=<x>,<y> will depend on xrange and yrange.



   [1m36.  Financebars[0m


   The [1mfinancebars [22mstyle is only relevant for 2D data plotting of
   financial data.  It requires 1 x coordinate (usually a date) and 4 y
   values (prices).

        5 columns:   date  open  low  high  close

   An additional (6th) input column may be used to provide variable
   (per-record) color information (see [1mlinecolor [22mand [1mrgbcolor vari-[0m
   [1mable[22m).

   The symbol is a vertical line segment, located horizontally at the x
   coordinate and limited vertically by the high and low prices.  A
   horizontal tic on the left marks the opening price and one on the
   right marks the closing price.  The length of these tics may be
   changed by [1mset bars[22m.  The symbol will be unchanged if the high and
   low prices are interchanged.  See [1mset bars [22mand [1mcandlesticks[22m, and
   also the finance demo.



   [1m37.  Fsteps[0m


   The [1mfsteps [22mstyle is only relevant to 2D plotting.  It connects con-
   secutive points with two line segments: the first from (x1,y1) to
   (x1,y2) and the second from (x1,y2) to (x2,y2).  The input column
   requires are the same as for plot styles [1mlines [22mand [1mpoints[22m.  The dif-
   ference between [1mfsteps [22mand [1msteps [22mis that [1mfsteps [22mtraces first the
   change in y and then the change in x.  [1msteps [22mtraces first the change
   in x and then the change in y.











   GNUPLOT 4.1                                                       54


   See also steps demo.



   [1m38.  Fillsteps[0m


   The [1mfillsteps [22mstyle is exactly like [1msteps [22mexcept that the area
   between the curve and y=0 is filled in the current fill style.  See
   [1msteps[22m.



   [1m39.  Histeps[0m


   The [1mhisteps [22mstyle is only relevant to 2D plotting.  It is intended
   for plotting histograms.  Y-values are assumed to be centered at the
   x-values; the point at x1 is represented as a horizontal line from
   ((x0+x1)/2,y1) to ((x1+x2)/2,y1).  The lines representing the end
   points are extended so that the step is centered on at x.  Adjacent
   points are connected by a vertical line at their average x, that is,
   from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).  The input column requires
   are the same as for plot styles [1mlines [22mand [1mpoints[22m.

   If [1mautoscale [22mis in effect, it selects the xrange from the data
   rather than the steps, so the end points will appear only half as
   wide as the others.  See also steps demo.

   [1mhisteps [22mis only a plotting style; [1mgnuplot [22mdoes not have the ability
   to create bins and determine their population from some data set.



   [1m40.  Histograms[0m


   The [1mhistograms [22mstyle is only relevant to 2D plotting.  It produces a
   bar chart from a sequence of parallel data columns. Each element of
   the [1mplot [22mcommand must specify a single input data source (e.g. one
   column of the input file), possibly with associated tic values or
   key titles.  Four styles of histogram layout are currently sup-
   ported.

         set style histogram clustered {gap <gapsize>}
         set style histogram errorbars {gap <gapsize>} {<linewidth>}
         set style histogram rowstacked
         set style histogram columnstacked

   The default style corresponds to [1mset style histogram clustered gap[0m
   [1m2[22m.  In this style, each set of parallel data values is collected
   into a group of boxes clustered at the x-axis coordinate correspond-
   ing to their sequential position (row #) in the selected datafile










   GNUPLOT 4.1                                                       55


   columns.  Thus if <n> datacolumns are selected, the first cluster is
   centered about x=1, and contains <n> boxes whose heights are taken
   from the first entry in the corresponding <n> data columns.  This is
   followed by a gap and then a second cluster of boxes centered about
   x=2 corresponding to the second entry in the respective data col-
   umns, and so on.  The default gap width of 2 indicates that the
   empty space between clusters is equivalent to the width of 2 boxes.
   All boxes derived from any one column are given the same fill color
   and/or pattern (see [1mset style fill[22m).

   Each cluster of boxes is derived from a single row of the input data
   file.  It is common in such input files that the first element of
   each row is a label. Labels from this column may be placed along the
   x-axis underneath the appropriate cluster of boxes with the [1mxticla-[0m
   [1mbels [22moption to [1musing[22m.

   The [1merrorbars [22mstyle is very similar to the [1mclustered [22mstyle, except
   that it requires additional columns of input for each entry. The
   first column holds the height (y value) of that box, exactly as for
   the [1mclustered [22mstyle.
        2 columns:        y yerr          bar extends from y-yerr to
   y+err
        3 columns:        y ymin yman     bar extends from ymin to ymax
   The appearance of the error bars is controlled by the current value
   of [1mset bars [22mand by the optional <linewidth> specification.

   Two styles of stacked histogram are supported, chosen by the command
   [1mset style histogram {rowstacked|columnstacked}[22m.  In these styles the
   data values from the selected columns are collected into stacks of
   boxes.  Positive values stack upwards from y=0; negative values
   stack downwards.  Mixed positive and negative values will produce
   both an upward stack and a downward stack.  The default stacking
   mode is [1mrowstacked[22m.

   The [1mrowstacked [22mstyle places a box resting on the x-axis for each
   data value in the first selected column; the first data value
   results in a box a x=1, the second at x=2, and so on.  Boxes corre-
   sponding to the second and subsequent data columns are layered on
   top of these, resulting in a stack of boxes at x=1 representing the
   first data value from each column, a stack of boxes at x=2 repre-
   senting the second data value from each column, and so on.  All
   boxes derived from any one column are given the same fill color
   and/or pattern (see [1mset style fill[22m).

   The [1mcolumnstacked [22mstyle is similar, except that each stack of boxes
   is built up from a single data column. Each data value from the
   first specified column yields a box in the stack at x=1, each data
   value from the second specified column yields a box in the stack at
   x=2, and so on.  In this style the color of each box is taken from
   the row number, rather than the column number, of the corresponding
   data field.

   Box widths may be modified using the [1mset boxwidth [22mcommand.  Box fill










   GNUPLOT 4.1                                                       56


   styles may be set using the [1mset style fill [22mcommand.

   Histograms always use the x1 axis, but may use either y1 or y2.  If
   a plot contains both histograms and other plot styles, the non-his-
   togram plot elements may use either the x1 or the x2 axis.

   Examples: Suppose that the input file contains data values in col-
   umns 2, 4, 6, ...  and error estimates in columns 3, 5, 7, ...  This
   example plots the values in columns 2 and 4 as a histogram of clus-
   tered boxes (the default style).  Because we use iteration in the
   plot command, any number of data columns can be handled in a single
   command. See [1miteration[22m.

         set boxwidth 0.9 relative
         set style data histograms
         set style histogram cluster
         set style fill solid 1.0 border lt -1
         plot for [COL=2:4:2] 'file.dat' using COL

   This will produce a plot with clusters of two boxes (vertical bars)
   centered at each integral value on the x axis.  If the first column
   of the input file contains labels, they may be placed along the x-
   axis using the variant command

         plot for [COL=2:4:2] 'file.dat' using COL:xticlabels(1)

   If the file contains both magnitude and range information for each
   value, then error bars can be added to the plot.  The following com-
   mands will add error bars extending from (y-<error>) to (y+<error>),
   capped by horizontal bar ends drawn the same width as the box
   itself. The error bars and bar ends are drawn with linewidth 2,
   using the border linetype from the current fill style.

         set bars fullwidth
         set style fill solid 1 border lt -1
         set style histogram errorbars gap 2 lw 2
         plot for [COL=2:4:2] 'file.dat' using COL:COL+1

   To plot the same data as a rowstacked histogram.  Just to be differ-
   ent, this example lists the separate columns explicitly rather than
   using iteration.

         set style histogram rowstacked
         plot 'file.dat' using 2, '' using 4:xtic(1)

   This will produce a plot in which each vertical bar corresponds to
   one row of data.  Each vertical bar contains a stack of two seg-
   ments, corresponding in height to the values found in columns 2 and
   4 of the datafile.


   Finally, the commands











   GNUPLOT 4.1                                                       57


         set style histogram columnstacked
         plot 'file.dat' using 2, '' using 4

   will produce two vertical stacks, one for each column of data.  The
   stack at x=1 will contain a box for each entry in column 2 of the
   datafile.  The stack at x=2 will contain a box for each parallel
   entry in column 4 of the datafile.  Because this interchanges gnu-
   plot's usual interpretation of input rows and columns, the specifi-
   cation of key titles and x-axis tic labels must also be modified
   accordingly. See the comments given below.

         set style histogram columnstacked
         plot '' u 5:key(1)            # uses first column to generate
   key titles
         plot '' u 5 title columnhead  # uses first row to generate
   xtic labels

   Note that the two examples just given present exactly the same data
   values, but in different formats.




        [1m40.1.  Newhistogram[0m


        Syntax:

             newhistogram {"<title>"} {lt <linetype>} {fs <fillstyle>}
        {at <x-coord>}

        More than one set of histograms can appear in a single plot. In
        this case you can force a gap between them, and a separate
        label for each set, by using the [1mnewhistogram [22mcommand.  For
        example

              set style histogram  cluster
              plot newhistogram "Set A", 'a' using 1, '' using 2, ''
        using 3, \
                   newhistogram "Set B", 'b' using 1, '' using 2, ''
        using 3

        The labels "Set A" and "Set B" will appear beneath the respec-
        tive sets of histograms, under the overall x axis label.

        The newhistogram command can also be used to force histogram
        coloring to begin with a specific color (linetype). By default
        colors will continue to increment successively even across his-
        togram boundaries. Here is an example using the same coloring
        for multiple histograms
              plot newhistogram "Set A" lt 4, 'a' using 1, '' using 2,
        '' using 3, \
                   newhistogram "Set B" lt 4, 'b' using 1, '' using 2,










   GNUPLOT 4.1                                                       58


        '' using 3

        Similarly you can force the next histogram to begin with a
        specified fillstyle.  If the fillstyle is set to [1mpattern[22m, then
        the pattern used for filling will be incremented automatically.

        The [1mat <x-coord> [22moption sets the x coordinate position of the
        following histogram to <x-coord>. For example

               set style histogram cluster
               set style data histogram
               set style fill solid 1.0 border -1
               set xtic 1 offset character 0,0.3
               plot newhistogram "Set A", \
                    'file.dat' u 1 t 1, '' u 2 t 2, \
                    newhistogram "Set B" at 8, \
                    'file.dat' u 2 t 2, '' u 2 t 2

        will position the second histogram to start at x=8.



        [1m40.2.  Automated iteration over multiple columns[0m


        If you want to create a histogram from many columns of data in
        a single file, it is very convenient to use the plot iteration
        feature.  See [1miteration[22m.  For example, to create stacked his-
        tograms of the data in columns 3 through 8

              set style histogram columnstacked
              plot for [i=3:8] "datafile" using i title columnhead



   [1m41.  Image[0m


   The [1mimage[22m, [1mrgbimage[22m, and [1mrgbalpha [22mplotting styles all project a uni-
   formly sampled grid of data values onto a plane  in either 2D or 3D.
   The input data may be an actual bitmapped image, perhaps converted
   from a standard format such as PNG, or a simple array of numerical
   values.

   This figure illustrates generation of a heat map from an array of
   scalar values.  The current palette is used to map each value onto
   the color assigned to the corresponding pixel.
         plot '-' matrix with image
         5 4 3 1 0
         2 2 0 0 1
         0 0 0 1 0
         0 1 2 4 3
         e










   GNUPLOT 4.1                                                       59


         e

   Each pixel (data point) of the input 2D image will become a rectan-
   gle or parallelipiped in the plot. The coordinates of each data
   point will determine the center of the parallelipiped.  That is, an
   M x N set of data will form an image with M x N pixels.  This is
   different from the pm3d plotting style, where an M x N set of data
   will form a surface of (M-1) x (N-1) elements.  The scan directions
   for a binary image data grid can be further controlled by additional
   keywords. See [1mbinary keywords flipx[22m, [1mkeywords center[22m, and [1mkeywords[0m
   [1mrotate[22m.

   Image data can be scaled to fill a particular rectangle within a 2D
   plot coordinate system by specifying the x and y extent of each
   pixel.  See [1mbinary keywords dx [22mand [1mdy[22m. To generate the figure at the
   right, the same input image was placed multiple times, each with a
   specified dx, dy, and origin. The input PNG image of a building is
   50x128 pixels.  The tall building was drawn by mapping this using
   [1mdx=0.5 dy=1.5[22m.  The short building used a mapping [1mdx=0.5 dy=0.35[22m.

   The [1mimage [22mstyle handles input pixels containing a grayscale or color
   palette value. Thus 2D plots ([1mplot [22mcommand) require 3 columns of
   data (x,y,value), while 3D plots ([1msplot [22mcommand) require 4 columns
   of data (x,y,z,value).

   The [1mrgbimage [22mstyle handles input pixels that are described by three
   separate values for the red, green, and blue components.  Thus 5D
   data (x,y,r,g,b) is needed for [1mplot [22mand 6D data (x,y,z,r,g,b) for
   [1msplot[22m.  The individual red, green, and blue components are assumed
   to lie in the range [0:255].

   The [1mrgbalpha [22mstyle handles input pixels that contain alpha channel
   (transparency) information in addition to the red, green, and blue
   components.  Thus 6D data (x,y,r,g,b,a) is needed for [1mplot [22mand 7D
   data (x,y,z,r,g,b,a) for [1msplot[22m.  The r, g, b, and alpha components
   are assumed to lie in the range [0:255].




        [1m41.1.  Transparency[0m


        The [1mrgbalpha [22mplotting style assumes that each pixel of input
        data contains an alpha value in the range [0:255].  A pixel
        with alpha = 0 is purely transparent and does not alter the
        underlying contents of the plot. A pixel with alpha = 255 is
        purely opaque.  All terminal types can handle these two extreme
        cases.  A pixel with 0 < alpha < 255 is partially transparent.
        Only a few terminal types can handle this correctly; other ter-
        minals will approximate this by treating alpha as being either
        0 or 255.











   GNUPLOT 4.1                                                       60


        [1m41.2.  Image failsafe[0m


        Some terminal drivers provide code to optimize rendering of
        image data within a rectangular 2D area.  However this code is
        known to be imperfect.  This optimized code may be disabled by
        using the keyword [1mfailsafe[22m. E.g.

              plot 'data' with image failsafe



   [1m42.  Impulses[0m


   The [1mimpulses [22mstyle displays a vertical line from y=0 to the y value
   of each point (2D) or from z=0 to the z value of each point (3D).
   Note that the y or z values may be negative.  Data from additional
   columns can be used to control the color of each impulse.  To use
   this style effectively in 3D plots, it is useful to choose thick
   lines (linewidth > 1). This approximates a 3D bar chart.

        1 column:   y
        2 columns:  x  y     # line from [x,0] to [x,y]  (2D)
        3 columns:  x  y  z  # line from [x,y,0] to [x,y,z] (3D)




   [1m43.  Labels[0m


   The [1mlabels [22mstyle reads coordinates and text from a data file and
   places the text string at the corresponding 2D or 3D position.  3 or
   4 input columns of basic data are required.  Additional input col-
   umns may be used to provide information such as variable font size
   or text color (see [1mrgbcolor variable[22m).

        3 columns:  x  y  string    # 2D version
        4 columns:  x  y  z  string # 3D version

   The font, color, rotation angle and other properties of the printed
   text may be specified as additional command options (see [1mset label[22m).
   The example below generates a 2D plot with text labels constructed
   from the city whose name is taken from column 1 of the input file,
   and whose geographic coordinates are in columns 4 and 5. The font
   size is calculated from the value in column 3, in this case the pop-
   ulation.

     CityName(String,Size) = sprintf("{/=%d %s}", Scale(Size), String)
     plot 'cities.dat' using 5:4:(CityName(stringcolumn(1),$3)) with
   labels











   GNUPLOT 4.1                                                       61


   If we did not want to adjust the font to a different size for each
   city, the command would be much simpler:

     plot 'cities.dat' using 5:4:1 with labels font "Times,8"

   The [1mlabels [22mstyle can also be used in 3D plots. In this case four
   input column specifiers are required, corresponding to X Y Z and
   text.

     splot 'datafile' using 1:2:3:4 with labels

   See also [1mdatastrings[22m, [1mset style data[22m.



   [1m44.  Lines[0m


   The [1mlines [22mstyle connects adjacent points with straight line seg-
   ments.  It may be used in either 2D or 3D plots. The basic form
   requires 1, 2, or 3 columns of input data.  Additional input columns
   may be used to provide information such as variable line color (see
   [1mrgbcolor variable[22m).

   2D form
        1 column:   y       # implicit x from row number
        2 columns:  x  y
   3D form
        1 column:   z       # implicit x from row, y from index
        3 columns:  x  y  z

   See also [1mlinetype[22m, [1mlinewidth[22m, and [1mlinestyle[22m.



   [1m45.  Linespoints[0m


   The [1mlinespoints [22mstyle connects adjacent points with straight line
   segments and then goes back to draw a small symbol at each point.
   The command [1mset pointsize [22mmay be used to change the default size of
   the points.  1 or 2 columns of basic input data are required in 2D
   plots; 1 or 3 columns are required if 3D plots.  See [1mstyle lines[22m.
   Additional input columns may be used to provide information such as
   variable point size or line color.

   The [1mpointinterval [22m(short form [1mpi[22m) property of the linetype can be
   used to control whether or not every point in the plot is given a
   symbol.  For example, 'with lp pi 3' will draw line segments through
   every data point, but will only place a symbol on every 3rd point.
   A negative value for [1mpointinterval [22mwill erase the portion of line
   segment that passes underneath the symbol. The size of the erased
   portion is controlled by [1mset pointintervalbox[22m.










   GNUPLOT 4.1                                                       62


   [1mlinespoints [22mmay be abbreviated [1mlp[22m.



   [1m46.  Points[0m


   The [1mpoints [22mstyle displays a small symbol at each point.  The command
   [1mset pointsize [22mmay be used to change the default size of the points.
   1 or 2 columns of basic input data are required in 2D plots; 1 or 3
   columns are required in 3D plots.  See [1mstyle lines[22m.  Additional
   input columns may be used to provide information such as variable
   point size or variable point color.




   [1m47.  Polar[0m


   Polar plots are not really a separate plot style but are listed here
   for completeness.  The option [1mset polar [22mtells gnuplot to interpret
   input 2D coordinates as <angle>,<radius> rather than <x>,<y>.  Many,
   but not all, 2D plotting styles work in polar mode.  The figure
   shows a combination of plot styles [1mlines [22mand [1mfilledcurves[22m.  See [1mset[0m
   [1mpolar[22m, [1mset rrange[22m, [1mset size square[22m.




   [1m48.  Steps[0m


   The [1msteps [22mstyle is only relevant to 2D plotting.  It connects con-
   secutive points with two line segments: the first from (x1,y1) to
   (x2,y1) and the second from (x2,y1) to (x2,y2).  The input column
   requires are the same as for plot styles [1mlines [22mand [1mpoints[22m.  The dif-
   ference between [1mfsteps [22mand [1msteps [22mis that [1mfsteps [22mtraces first the
   change in y and then the change in x.  [1msteps [22mtraces first the change
   in x and then the change in y.  To fill the area between the curve
   and the baseline at y=0, use [1mfillsteps[22m.  See also steps demo.




   [1m49.  Rgbalpha[0m


   See [1mimage[22m.














   GNUPLOT 4.1                                                       63


   [1m50.  Rgbimage[0m


   See [1mimage[22m.



   [1m51.  Vectors[0m


   The 2D [1mvectors [22mstyle draws a vector from (x,y) to
   (x+xdelta,y+ydelta).  The 3D [1mvectors [22mstyle is similar, but requires
   six columns of basic data.  A small arrowhead is drawn at the end of
   each vector.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  z  xdelta  ydelta  zdelta

   In both cases, an additional input column (5th in 2D, 7th in 3D) may
   be used to provide variable (per-datapoint) color information.  (see
   [1mlinecolor [22mand [1mrgbcolor variable[22m).

   splot with vectors is supported only for [1mset mapping cartesian[22m.

   The keywords "with vectors" may be followed by an in-line arrow
   style specifications, a reference to a predefined arrow style, or a
   request to read the index of the desired arrow style for each vector
   from a separate column.  Note: If you choose "arrowstyle variable"
   it will fill in all arrow properties at the time the corresponding
   vector is drawn; you cannot mix this keyword with other line or
   arrow style qualifiers in the plot command.

        plot ... with vectors filled heads
        plot ... with vectors arrowstyle 3
        plot ... using 1:2:3:4:5 with vectors arrowstyle variable

   See [1marrowstyle [22mfor more details.

   Example:
         plot 'file.dat' using 1:2:3:4 with vectors head filled lt 2
         splot 'file.dat' using 1:2:3:(1):(1):(1) with vectors filled
   head lw 2

   [1mset clip one [22mand [1mset clip two [22maffect vectors drawn in 2D.  Please
   see [1mset clip [22mand [1marrowstyle[22m.



   [1m52.  Xerrorbars[0m


   The [1mxerrorbars [22mstyle is only relevant to 2D data plots.  [1mxerrorbars[0m
   is like [1mpoints[22m, except that a horizontal error bar is also drawn.










   GNUPLOT 4.1                                                       64


   At each point (x,y), a line is drawn from (xlow,y) to (xhigh,y) or
   from (x-xdelta,y) to (x+xdelta,y), depending on how many data col-
   umns are provided.  A tic mark is placed at the ends of the error
   bar (unless [1mset bars [22mis used---see [1mset bars [22mfor details).  The basic
   style requires either 3 or 4 columns:

        3 columns:  x  y  xdelta
        4 columns:  x  y  xlow  xhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.




   [1m53.  Xyerrorbars[0m


   The [1mxyerrorbars [22mstyle is only relevant to 2D data plots.  [1mxyerror-[0m
   [1mbars [22mis like [1mpoints[22m, except that horizontal and vertical error bars
   are also drawn.  At each point (x,y), lines are drawn from (x,y-
   ydelta) to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y) or
   from (x,ylow) to (x,yhigh) and from (xlow,y) to (xhigh,y), depending
   upon the number of data columns provided.  A tic mark is placed at
   the ends of the error bar (unless [1mset bars [22mis used---see [1mset bars[0m
   for details).  Either 4 or 6 input columns are required.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   If data are provided in an unsupported mixed form, the [1musing [22mfilter
   on the [1mplot [22mcommand should be used to set up the appropriate form.
   For example, if the data are of the form (x,y,xdelta,ylow,yhigh),
   then you can use

         plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars

   An additional input column (5th or 7th) may be used to provide vari-
   able (per-datapoint) color information.




   [1m54.  Yerrorbars[0m


   The [1myerrorbars [22m(or [1merrorbars[22m) style is only relevant to 2D data
   plots.  [1myerrorbars [22mis like [1mpoints[22m, except that a vertical error bar
   is also drawn.  At each point (x,y), a line is drawn from (x,y-
   ydelta) to (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending on
   how many data columns are provided.  A tic mark is placed at the
   ends of the error bar (unless [1mset bars [22mis used---see [1mset bars [22mfor
   details).  Either 3 or 4 input columns are required.










   GNUPLOT 4.1                                                       65


        3 columns:  x  y  ydelta
        4 columns:  x  y  ylow  yhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.

   See also errorbar demo.



   [1m55.  Xerrorlines[0m


   The [1mxerrorlines [22mstyle is only relevant to 2D data plots.  [1mxerror-[0m
   [1mlines [22mis like [1mlinespoints[22m, except that a horizontal error line is
   also drawn. At each point (x,y), a line is drawn from (xlow,y) to
   (xhigh,y) or from (x-xdelta,y) to (x+xdelta,y), depending on how
   many data columns are provided. A tic mark is placed at the ends of
   the error bar (unless [1mset bars [22mis used---see [1mset bars [22mfor details).
   The basic style requires either 3 or 4 columns:

        3 columns:  x  y  xdelta
        4 columns:  x  y  xlow  xhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.




   [1m56.  Xyerrorlines[0m


   The [1mxyerrorlines [22mstyle is only relevant to 2D data plots.  [1mxyerror-[0m
   [1mlines [22mis like [1mlinespoints[22m, except that horizontal and vertical error
   bars are also drawn. At each point (x,y), lines are drawn from (x,y-
   ydelta) to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y) or
   from (x,ylow) to (x,yhigh) and from (xlow,y) to (xhigh,y), depending
   upon the number of data columns provided. A tic mark is placed at
   the ends of the error bar (unless [1mset bars [22mis used---see [1mset bars[0m
   for details).  Either 4 or 6 input columns are required.

        4 columns:  x  y  xdelta  ydelta
        6 columns:  x  y  xlow  xhigh  ylow  yhigh

   If data are provided in an unsupported mixed form, the [1musing [22mfilter
   on the [1mplot [22mcommand should be used to set up the appropriate form.
   For example, if the data are of the form (x,y,xdelta,ylow,yhigh),
   then you can use

         plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorlines

   An additional input column (5th or 7th) may be used to provide










   GNUPLOT 4.1                                                       66


   variable (per-datapoint) color information.




   [1m57.  Yerrorlines[0m


   The [1myerrorlines [22m(or [1merrorlines[22m) style is only relevant to 2D data
   plots. [1myerrorlines [22mis like [1mlinespoints[22m, except that a vertical error
   line is also drawn. At each point (x,y), a line is drawn from (x,y-
   ydelta) to (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending on
   how many data columns are provided. A tic mark is placed at the ends
   of the error bar (see [1mset bars [22mfor details).  Either 3 or 4 input
   columns are required.

        3 columns:  x  y  ydelta
        4 columns:  x  y  ylow  yhigh

   An additional input column (4th or 5th) may be used to provide
   information such as variable point color.

   See also errorbar demo.



   [1m58.  3D (surface) plots[0m


   Surface plots are generated using the [1msplot [22mcommand rather than the
   [1mplot [22mcommand. The style [1mwith lines [22mdraws a surface made from a grid
   of lines.  Solid surfaces can be drawn using the style [1mwith pm3d[22m.
   Usually the surface is displayed at some arbitrary viewing angle,
   such that it clearly represents a 3D surface.  In this case the X,
   Y, and Z axes are all visible in the plot. The illusion of 3D is
   enhanced by choosing hidden line removal or depth-sorted surface
   elements.  See [1mhidden3d [22mand [1mpm3d depthorder[22m.  The [1msplot [22mcommand can
   also calculate and draw contour lines corresponding to constant Z
   values. These contour lines may be drawn onto the surface itself, or
   projected onto the XY plane. See [1mset contour[22m.








        [1m58.1.  2D projection (set view map)[0m


        An important special case of the [1msplot [22mcommand is to map the Z
        coordinate onto a 2D surface by projecting the plot along the Z










   GNUPLOT 4.1                                                       67


        axis.  See [1mset view map[22m.  This plot mode can be used to gener-
        ate contour plots and heat maps.






        [1m59.  Commands[0m


        This section lists the commands acceptable to [1mgnuplot [22min alpha-
        betical order.  Printed versions of this document contain all
        commands; the text available interactively may not be complete.
        Indeed, on some systems there may be no commands at all listed
        under this heading.

        Note that in most cases unambiguous abbreviations for command
        names and their options are permissible, i.e., "[1mp f(x) w li[22m"
        instead of "[1mplot f(x) with lines[22m".

        In the syntax descriptions, braces ({}) denote optional argu-
        ments and a vertical bar (|) separates mutually exclusive
        choices.



        [1m60.  Cd[0m


        The [1mcd [22mcommand changes the working directory.

        Syntax:
              cd '<directory-name>'

        The directory name must be enclosed in quotes.

        Examples:
              cd 'subdir'
              cd ".."

        It is recommended that Windows users use single-quotes, because
        backslash [\] has special significance inside double-quotes and
        has to be escaped.  For example,
              cd "c:\newdata"
        fails, but
              cd 'c:\newdata'
              cd "c:\\newdata"
        work as expected.














   GNUPLOT 4.1                                                       68


        [1m61.  Call[0m


        The [1mcall [22mcommand is identical to the load command with one
        exception: you can have up to ten additional parameters to the
        command (delimited according to the standard parser rules)
        which can be substituted into the lines read from the file.  As
        each line is read from the [1mcall[22med input file, it is scanned for
        the sequence [1m$ [22m(dollar-sign) followed by a digit (0--9).  If
        found, the sequence is replaced by the corresponding parameter
        from the [1mcall [22mcommand line.  If the parameter was specified as
        a string in the [1mcall [22mline, it is substituted without its
        enclosing quotes.  Sequence [1m$# [22mis replaced by the number of
        passed parameters.  [1m$ [22mfollowed by any character will be that
        character; e.g. use [1m$$ [22mto get a single [1m$[22m.  Providing more than
        ten parameters on the [1mcall [22mcommand line will cause an error.  A
        parameter that was not provided substitutes as nothing.  Files
        being [1mcall[22med may themselves contain [1mcall [22mor [1mload [22mcommands.

        Syntax:
              call "<input-file>" <parameter-0> <parm-1> ... <parm-9>

        The name of the input file must be enclosed in quotes, and it
        is recommended that parameters are similarly enclosed in quotes
        (future versions of gnuplot may treat quoted and unquoted argu-
        ments differently).

        Example:

        If the file 'calltest.gp' contains the line:
              print "argc=$# p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6
        p7=x$7x"

        entering the command:
              call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"

        will display:
              argc=7 p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2
        p7=xx

        NOTE: there is a clash in syntax with the datafile [1musing [22mcall-
        back operator.  Use [1m$$n [22mor [1mcolumn(n) [22mto access column n from a
        datafile inside a [1mcall[22med datafile plot.



        [1m62.  Clear[0m


        The [1mclear [22mcommand erases the current screen or output device as
        specified by [1mset output[22m.  This usually generates a formfeed on
        hardcopy devices.  Use [1mset terminal [22mto set the device type.











   GNUPLOT 4.1                                                       69


        For some terminals [1mclear [22merases only the portion of the plot-
        ting surface defined by [1mset size[22m, so for these it can be used
        in conjunction with [1mset multiplot [22mto create an inset.

        Example:
              set multiplot
              plot sin(x)
              set origin 0.5,0.5
              set size 0.4,0.4
              clear
              plot cos(x)
              unset multiplot

        Please see [1mset multiplot[22m, [1mset size[22m, and [1mset origin [22mfor details
        of these commands.



        [1m63.  Do[0m


        Syntax:
              do for <iteration-spec> {
                   <commands>
                   <commands>
              }
        Execute a sequence of commands multiple times.  The commands
        must be enclosed in curly brackets, and the opening "{" must be
        on the same line as the [1mdo [22mkeyword.  This command cannot be
        used with old-style (un-bracketed) if/else statements.  See [1mif[22m.
        For examples of iteration specifiers, see [1miteration[22m.  Example:
              set multiplot layout 2,2
              do for [name in "A B C D"] {
                  filename = name . ".dat"
                  set title sprintf("Condition %s",name)
                  plot filename title name
              }
              unset multiplot



        [1m64.  Evaluate[0m


        The [1mevaluate [22mcommand executes the commands given as an argument
        string.  Newline characters are not allowed within the string.

        Syntax:
              eval <string expression>

        This is especially useful for a repetition of similar commands.

        Example:










   GNUPLOT 4.1                                                       70


              set_label(x, y, text) \
                = sprintf("set label '%s' at %f, %f point pt 5", text,
        x, y)
              eval set_label(1., 1., 'one/one')
              eval set_label(2., 1., 'two/one')
              eval set_label(1., 2., 'one/two')

        Please see [1msubstitution macros [22mfor another way to execute com-
        mands from a string.



        [1m65.  Exit[0m


        The commands [1mexit [22mand [1mquit[22m, as well as the END-OF-FILE charac-
        ter (usually Ctrl-D) terminate input from the current input
        stream: terminal session, pipe, and file input (pipe).

        If input streams are nested (inherited [1mload [22mscripts), then
        reading will continue in the parent stream. When the top level
        stream is closed, the program itself will exit.

        The command [1mexit gnuplot [22mwill immediately and unconditionally
        cause gnuplot to exit even if the input stream is multiply
        nested.  In this case any open output files may not be com-
        pleted cleanly. Example of use:

              bind "ctrl-x" "unset output; exit gnuplot"

        See help for [1mbatch/interactive [22mfor more details.



        [1m66.  Fit[0m


        The [1mfit [22mcommand can fit a user-supplied expression to a set of
        data points (x,z) or (x,y,z), using an implementation of the
        nonlinear least-squares (NLLS) Marquardt-Levenberg algorithm.
        Any user-defined variable occurring in the expression may serve
        as a fit parameter, but the return type of the expression must
        be real.

        Syntax:
              fit {<ranges>} <expression>
                  '<datafile>' {datafile-modifiers}
                  via '<parameter file>' | <var1>{,<var2>,...}

        Ranges may be specified to temporarily limit the data which is
        to be fitted; any out-of-range data points are ignored. The
        syntax is
              [{dummy_variable=}{<min>}{:<max>}],










   GNUPLOT 4.1                                                       71


        analogous to [1mplot[22m; see [1mplot ranges[22m.

        <expression> is any valid [1mgnuplot [22mexpression, although it is
        usual to use a previously user-defined function of the form
        f(x) or f(x,y).

        <datafile> is treated as in the [1mplot [22mcommand.  All the [1mplot[0m
        [1mdatafile [22mmodifiers ([1musing[22m, [1mevery[22m,...) except [1msmooth [22mand the
        deprecated [1mthru [22mare applicable to [1mfit[22m. See [1mplot datafile[22m.

        The default data formats for fitting functions with a single
        independent variable, z=f(x), are z or x:z.  That is, if there
        is only a single column then it is the dependent variable and
        the line numbers is the independent variable.  If there are two
        columns, the first is the independent variable and the second
        is the dependent variable.

        Those formats can be changed with the datafile [1musing [22mqualifier,
        for example to take the z value from a different column or to
        calculate it from several columns.  A third [1musing [22mqualifier (a
        column number or an expression), if present, is interpreted as
        the standard deviation of the corresponding z value and is used
        to compute a weight for the datum, 1/s**2.  Otherwise, all data
        points are weighted equally, with a weight of one. Note that if
        you don't specify a [1musing [22moption at all, no z standard devia-
        tions are read from the datafile even if it does have a third
        column, so you'll always get unit weights.

        To fit a function with two independent variables, z=f(x,y), the
        required format is [1musing [22mwith four items, x:y:z:s.  The com-
        plete format must be given---no default columns are assumed for
        a missing token.  Weights for each data point are evaluated
        from 's' as above.  If error estimates are not available, a
        constant value can be specified as a constant expression (see
        [1mplot datafile using[22m), e.g., [1musing 1:2:3:(1)[22m.

        The fit function may have up to five independent variables.
        There must be two more [1musing [22mqualifiers than there are indepen-
        dent variables, unless there is only one variable.  The allowed
        formats, and the default dummy variable names, are as follows:

              z
              x:z
              x:z:s
              x:y:z:s
              x:y:t:z:s
              x:y:t:u:z:s
              x:y:t:u:v:z:s

        The dummy variable names may be changed with ranges as noted
        above.  The first range corresponds to the first [1musing [22mspec,
        etc.  A range may also be given for z (the dependent variable),
        but that name cannot be changed.










   GNUPLOT 4.1                                                       72


        Multiple datasets may be simultaneously fit with functions of
        one independent variable by making y a 'pseudo-variable', e.g.,
        the dataline number, and fitting as two independent variables.
        See [1mfit multi-branch[22m.

        The [1mvia [22mqualifier specifies which parameters are to be
        adjusted, either directly, or by referencing a parameter file.

        Examples:
              f(x) = a*x**2 + b*x + c
              g(x,y) = a*x**2 + b*y**2 + c*x*y
              FIT_LIMIT = 1e-6
              fit f(x) 'measured.dat' via 'start.par'
              fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
              fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
              fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c
              fit a0 + a1*x/(1 + a2*x/(1 + a3*x)) 'measured.dat' via
        a0,a1,a2,a3
              fit a*x + b*y 'surface.dat' using 1:2:3:(1) via a,b
              fit [*:*][yaks=*:*] a*x+b*yaks 'surface.dat' u 1:2:3:(1)
        via a,b
              fit a*x + b*y + c*t 'foo.dat' using 1:2:3:4:(1) via a,b,c
              h(x,y,t,u,v) = a*x + b*y + c*t + d*u + e*v
              fit h(x,y,t,u,v) 'foo.dat' using 1:2:3:4:5:6:(1) via
        a,b,c,d,e

        After each iteration step, detailed information about the cur-
        rent state of the fit is written to the display.  The same
        information about the initial and final states is written to a
        log file, "fit.log".  This file is always appended to, so as to
        not lose any previous fit history;  it should be deleted or
        renamed as desired. By using the command [1mset fit logfile[22m, the
        name of the log file can be changed.

        If gnuplot was built with this option, and you activated it
        using [1mset fit errorvariables[22m, the error for each fitted parame-
        ter will be stored in a variable named like the parameter, but
        with "_err" appended.  Thus the errors can be used as input for
        further computations.

        The fit may be interrupted by pressing Ctrl-C.  After the cur-
        rent iteration completes, you have the option to (1) stop the
        fit and accept the current parameter values, (2) continue the
        fit, (3) execute a [1mgnuplot [22mcommand as specified by the environ-
        ment variable FIT_SCRIPT.  The default for FIT_SCRIPT is
        [1mreplot[22m, so if you had previously plotted both the data and the
        fitting function in one graph, you can display the current
        state of the fit.

        Once [1mfit [22mhas finished, the [1mupdate [22mcommand may be used to store
        final values in a file for subsequent use as a parameter file.
        See [1mupdate [22mfor details.











   GNUPLOT 4.1                                                       73


             [1m66.1.  Adjustable parameters[0m


             There are two ways that [1mvia [22mcan specify the parameters to
             be adjusted, either directly on the command line or indi-
             rectly, by referencing a parameter file.  The two use dif-
             ferent means to set initial values.

             Adjustable parameters can be specified by a comma-sepa-
             rated list of variable names after the [1mvia [22mkeyword.  Any
             variable that is not already defined is created with an
             initial value of 1.0.  However, the fit is more likely to
             converge rapidly if the variables have been previously
             declared with more appropriate starting values.

             In a parameter file, each parameter to be varied and a
             corresponding initial value are specified, one per line,
             in the form
                   varname = value

             Comments, marked by '#', and blank lines are permissible.
             The special form
                   varname = value       # FIXED

             means that the variable is treated as a 'fixed parameter',
             initialized by the parameter file, but not adjusted by
             [1mfit[22m.  For clarity, it may be useful to designate variables
             as fixed parameters so that their values are reported by
             [1mfit[22m.  The keyword [1m# FIXED [22mhas to appear in exactly this
             form.




             [1m66.2.  Short introduction[0m


             [1mfit [22mis used to find a set of parameters that 'best' fits
             your data to your user-defined function.  The fit is
             judged on the basis of the sum of the squared differences
             or 'residuals' (SSR) between the input data points and the
             function values, evaluated at the same places.  This quan-
             tity is often called 'chisquare' (i.e., the Greek letter
             chi, to the power of 2).  The algorithm attempts to mini-
             mize SSR, or more precisely, WSSR, as the residuals are
             'weighted' by the input data errors (or 1.0) before being
             squared; see [1mfit error_estimates [22mfor details.

             That's why it is called 'least-squares fitting'.  Let's
             look at an example to see what is meant by 'non-linear',
             but first we had better go over some terms.  Here it is
             convenient to use z as the dependent variable for user-
             defined functions of either one independent variable,










   GNUPLOT 4.1                                                       74


             z=f(x), or two independent variables, z=f(x,y).  A parame-
             ter is a user-defined variable that [1mfit [22mwill adjust, i.e.,
             an unknown quantity in the function declaration.  Linear-
             ity/non-linearity refers to the relationship of the depen-
             dent variable, z, to the parameters which [1mfit [22mis adjust-
             ing, not of z to the independent variables, x and/or y.
             (To be technical, the second {and higher} derivatives of
             the fitting function with respect to the parameters are
             zero for a linear least-squares problem).

             For linear least-squares (LLS), the user-defined function
             will be a sum of simple functions, not involving any
             parameters, each multiplied by one parameter.  NLLS han-
             dles more complicated functions in which parameters can be
             used in a large number of ways.  An example that illus-
             trates the difference between linear and nonlinear least-
             squares is the Fourier series.  One member may be written
             as
                  z=a*sin(c*x) + b*cos(c*x).
             If a and b are the unknown parameters and c is constant,
             then estimating values of the parameters is a linear
             least-squares problem.  However, if c is an unknown param-
             eter, the problem is nonlinear.

             In the linear case, parameter values can be determined by
             comparatively simple linear algebra, in one direct step.
             However LLS is a special case which is also solved along
             with more general NLLS problems by the iterative procedure
             that [1mgnuplot [22muses.  [1mfit [22mattempts to find the minimum by
             doing a search.  Each step (iteration) calculates WSSR
             with a new set of parameter values.  The Marquardt-Leven-
             berg algorithm selects the parameter values for the next
             iteration.  The process continues until a preset criterion
             is met, either (1) the fit has "converged" (the relative
             change in WSSR is less than FIT_LIMIT), or (2) it reaches
             a preset iteration count limit, FIT_MAXITER (see [1mfit con-[0m
             [1mtrol variables[22m).  The fit may also be interrupted and sub-
             sequently halted from the keyboard (see [1mfit[22m).  The user
             variable FIT_CONVERGED contains 1 if the previous fit com-
             mand terminated due to convergence; it contains 0 if the
             previous fit terminated for any other reason.

             Often the function to be fitted will be based on a model
             (or theory) that attempts to describe or predict the be-
             haviour of the data.  Then [1mfit [22mcan be used to find values
             for the free parameters of the model, to determine how
             well the data fits the model, and to estimate an error
             range for each parameter.  See [1mfit error_estimates[22m.

             Alternatively, in curve-fitting, functions are selected
             independent of a model (on the basis of experience as to
             which are likely to describe the trend of the data with
             the desired resolution and a minimum number of










   GNUPLOT 4.1                                                       75


             parameters*functions.)  The [1mfit [22msolution then provides an
             analytic representation of the curve.

             However, if all you really want is a smooth curve through
             your data points, the [1msmooth [22moption to [1mplot [22mmay be what
             you've been looking for rather than [1mfit[22m.



             [1m66.3.  Error estimates[0m


             In [1mfit[22m, the term "error" is used in two different con-
             texts, data error estimates and parameter error estimates.

             Data error estimates are used to calculate the relative
             weight of each data point when determining the weighted
             sum of squared residuals, WSSR or chisquare.  They can
             affect the parameter estimates, since they determine how
             much influence the deviation of each data point from the
             fitted function has on the final values.  Some of the [1mfit[0m
             output information, including the parameter error esti-
             mates, is more meaningful if accurate data error estimates
             have been provided.

             The 'statistical overview' describes some of the [1mfit [22mout-
             put and gives some background for the 'practical guide-
             lines'.




                  [1m66.3.1.  Statistical overview[0m


                  The theory of non-linear least-squares (NLLS) is gen-
                  erally described in terms of a normal distribution of
                  errors, that is, the input data is assumed to be a
                  sample from a population having a given mean and a
                  Gaussian (normal) distribution about the mean with a
                  given standard deviation.  For a sample of suffi-
                  ciently large size, and knowing the population stan-
                  dard deviation, one can use the statistics of the
                  chisquare distribution to describe a "goodness of
                  fit" by looking at the variable often called
                  "chisquare".  Here, it is sufficient to say that a
                  reduced chisquare (chisquare/degrees of freedom,
                  where degrees of freedom is the number of datapoints
                  less the number of parameters being fitted) of 1.0 is
                  an indication that the weighted sum of squared devia-
                  tions between the fitted function and the data points
                  is the same as that expected for a random sample from
                  a population characterized by the function with the










   GNUPLOT 4.1                                                       76


                  current value of the parameters and the given stan-
                  dard deviations.

                  If the standard deviation for the population is not
                  constant, as in counting statistics where variance =
                  counts, then each point should be individually
                  weighted when comparing the observed sum of devia-
                  tions and the expected sum of deviations.

                  At the conclusion [1mfit [22mreports 'stdfit', the standard
                  deviation of the fit, which is the rms of the residu-
                  als, and the variance of the residuals, also called
                  'reduced chisquare' when the data points are
                  weighted.  The number of degrees of freedom (the num-
                  ber of data points minus the number of fitted parame-
                  ters) is used in these estimates because the parame-
                  ters used in calculating the residuals of the data-
                  points were obtained from the same data.  These val-
                  ues are exported to the variables
                        FIT_NDF = Number of degrees of freedom
                        FIT_WSSR = Weighted sum-of-squares residual
                        FIT_STDFIT = sqrt(WSSR/NDF)

                  To estimate confidence levels for the parameters, one
                  can use the minimum chisquare obtained from the fit
                  and chisquare statistics to determine the value of
                  chisquare corresponding to the desired confidence
                  level, but considerably more calculation is required
                  to determine the combinations of parameters which
                  produce such values.

                  Rather than determine confidence intervals, [1mfit[0m
                  reports parameter error estimates which are readily
                  obtained from the variance-covariance matrix after
                  the final iteration.  By convention, these estimates
                  are called "standard errors" or "asymptotic standard
                  errors", since they are calculated in the same way as
                  the standard errors (standard deviation of each
                  parameter) of a linear least-squares problem, even
                  though the statistical conditions for designating the
                  quantity calculated to be a standard deviation are
                  not generally valid for the NLLS problem.  The asymp-
                  totic standard errors are generally over-optimistic
                  and should not be used for determining confidence
                  levels, but are useful for qualitative purposes.

                  The final solution also produces a correlation matrix
                  indicating correlation of parameters in the region of
                  the solution; The main diagonal elements, autocorre-
                  lation, are always 1; if all parameters were indepen-
                  dent, the off-diagonal elements would be nearly 0.
                  Two variables which completely compensate each other
                  would have an off-diagonal element of unit magnitude,










   GNUPLOT 4.1                                                       77


                  with a sign depending on whether the relation is pro-
                  portional or inversely proportional.  The smaller the
                  magnitudes of the off-diagonal elements, the closer
                  the estimates of the standard deviation of each
                  parameter would be to the asymptotic standard error.



                  [1m66.3.2.  Practical guidelines[0m


                  If you have a basis for assigning weights to each
                  data point, doing so lets you make use of additional
                  knowledge about your measurements, e.g., take into
                  account that some points may be more reliable than
                  others.  That may affect the final values of the
                  parameters.

                  Weighting the data provides a basis for interpreting
                  the additional [1mfit [22moutput after the last iteration.
                  Even if you weight each point equally, estimating an
                  average standard deviation rather than using a weight
                  of 1 makes WSSR a dimensionless variable, as
                  chisquare is by definition.

                  Each fit iteration will display information which can
                  be used to evaluate the progress of the fit.  (An '*'
                  indicates that it did not find a smaller WSSR and is
                  trying again.)  The 'sum of squares of residuals',
                  also called 'chisquare', is the WSSR between the data
                  and your fitted function; [1mfit [22mhas minimized that.  At
                  this stage, with weighted data, chisquare is expected
                  to approach the number of degrees of freedom (data
                  points minus parameters).  The WSSR can be used to
                  calculate the reduced chisquare (WSSR/ndf) or stdfit,
                  the standard deviation of the fit, sqrt(WSSR/ndf).
                  Both of these are reported for the final WSSR.

                  If the data are unweighted, stdfit is the rms value
                  of the deviation of the data from the fitted func-
                  tion, in user units.

                  If you supplied valid data errors, the number of data
                  points is large enough, and the model is correct, the
                  reduced chisquare should be about unity.  (For
                  details, look up the 'chi-squared distribution' in
                  your favourite statistics reference.)  If so, there
                  are additional tests, beyond the scope of this over-
                  view, for determining how well the model fits the
                  data.

                  A reduced chisquare much larger than 1.0 may be due
                  to incorrect data error estimates, data errors not










   GNUPLOT 4.1                                                       78


                  normally distributed, systematic measurement errors,
                  'outliers', or an incorrect model function.  A plot
                  of the residuals, e.g., [1mplot 'datafile' using[0m
                  [1m1:($2-f($1))[22m, may help to show any systematic trends.
                  Plotting both the data points and the function may
                  help to suggest another model.

                  Similarly, a reduced chisquare less than 1.0 indi-
                  cates WSSR is less than that expected for a random
                  sample from the function with normally distributed
                  errors.  The data error estimates may be too large,
                  the statistical assumptions may not be justified, or
                  the model function may be too general, fitting fluc-
                  tuations in a particular sample in addition to the
                  underlying trends.  In the latter case, a simpler
                  function may be more appropriate.

                  You'll have to get used to both [1mfit [22mand the kind of
                  problems you apply it to before you can relate the
                  standard errors to some more practical estimates of
                  parameter uncertainties or evaluate the significance
                  of the correlation matrix.

                  Note that [1mfit[22m, in common with most NLLS implementa-
                  tions, minimizes the weighted sum of squared dis-
                  tances (y-f(x))**2.  It does not provide any means to
                  account for "errors" in the values of x, only in y.
                  Also, any "outliers" (data points outside the normal
                  distribution of the model) will have an exaggerated
                  effect on the solution.



             [1m66.4.  Control[0m


             There are a number of [1mgnuplot [22mvariables that can be
             defined to affect [1mfit[22m.  Those which can be defined once
             [1mgnuplot [22mis running are listed under 'control_variables'
             while those defined before starting [1mgnuplot [22mare listed
             under 'environment_variables'.




                  [1m66.4.1.  Control variables[0m


                  The default epsilon limit (1e-5) may be changed by
                  declaring a value for
                        FIT_LIMIT
                  When the sum of squared residuals changes between two
                  iteration steps by a factor less than this number










   GNUPLOT 4.1                                                       79


                  (epsilon), the fit is considered to have 'converged'.

                  The maximum number of iterations may be limited by
                  declaring a value for
                        FIT_MAXITER
                  A value of 0 (or not defining it at all)  means that
                  there is no limit.

                  If you need even more control about the algorithm,
                  and know the Marquardt-Levenberg algorithm well,
                  there are some more variables to influence it. The
                  startup value of [1mlambda [22mis normally calculated auto-
                  matically from the ML-matrix, but if you want to, you
                  may provide your own one with
                        FIT_START_LAMBDA
                  Specifying FIT_START_LAMBDA as zero or less will re-
                  enable the automatic selection. The variable
                        FIT_LAMBDA_FACTOR
                  gives the factor by which [1mlambda [22mis increased or
                  decreased whenever the chi-squared target function
                  increased or decreased significantly.  Setting
                  FIT_LAMBDA_FACTOR to zero re-enables the default fac-
                  tor of 10.0.

                  Other variables with the FIT_ prefix may be added to
                  [1mfit[22m, so it is safer not to use that prefix for user-
                  defined variables.

                  The variables FIT_SKIP and FIT_INDEX were used by
                  earlier releases of [1mgnuplot [22mwith a 'fit' patch called
                  [1mgnufit [22mand are no longer available.  The datafile
                  [1mevery [22mmodifier provides the functionality of
                  FIT_SKIP.  FIT_INDEX was used for multi-branch fit-
                  ting, but multi-branch fitting of one independent
                  variable is now done as a pseudo-3D fit in which the
                  second independent variable and [1musing [22mare used to
                  specify the branch.  See [1mfit multi-branch[22m.



                  [1m66.4.2.  Environment variables[0m


                  The environment variables must be defined before [1mgnu-[0m
                  [1mplot [22mis executed; how to do so depends on your oper-
                  ating system.

                        FIT_LOG
                  changes the name (and/or path) of the file to which
                  the fit log will be written from the default of
                  "fit.log" in the working directory. The default value
                  can be overwritten using the command [1mset fit logfile[22m.











   GNUPLOT 4.1                                                       80


                        FIT_SCRIPT
                  specifies a command that may be executed after an
                  user interrupt. The default is [1mreplot[22m, but a [1mplot [22mor
                  [1mload [22mcommand may be useful to display a plot cus-
                  tomized to highlight the progress of the fit.



             [1m66.5.  Multi-branch[0m


             In multi-branch fitting, multiple data sets can be simul-
             taneously fit with functions of one independent variable
             having common parameters by minimizing the total WSSR.
             The function and parameters (branch) for each data set are
             selected by using a 'pseudo-variable', e.g., either the
             dataline number (a 'column' index of -1) or the datafile
             index (-2), as the second independent variable.

             Example:  Given two exponential decays of the form,
             z=f(x), each describing a different data set but having a
             common decay time, estimate the values of the parameters.
             If the datafile has the format x:z:s, then
                  f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
                  fit f(x,y) 'datafile' using  1:-2:2:3  via a, b, tau

             For a more complicated example, see the file "hexa.fnc"
             used by the "fit.dem" demo.

             Appropriate weighting may be required since unit weights
             may cause one branch to predominate if there is a differ-
             ence in the scale of the dependent variable.  Fitting each
             branch separately, using the multi-branch solution as ini-
             tial values, may give an indication as to the relative
             effect of each branch on the joint solution.



             [1m66.6.  Starting values[0m


             Nonlinear fitting is not guaranteed to converge to the
             global optimum (the solution with the smallest sum of
             squared residuals, SSR), and can get stuck at a local min-
             imum.  The routine has no way to determine that;  it is up
             to you to judge whether this has happened.

             [1mfit [22mmay, and often will get "lost" if started far from a
             solution, where SSR is large and changing slowly as the
             parameters are varied, or it may reach a numerically
             unstable region (e.g., too large a number causing a float-
             ing point overflow) which results in an "undefined value"
             message or [1mgnuplot [22mhalting.










   GNUPLOT 4.1                                                       81


             To improve the chances of finding the global optimum, you
             should set the starting values at least roughly in the
             vicinity of the solution, e.g., within an order of magni-
             tude, if possible.  The closer your starting values are to
             the solution, the less chance of stopping at another mini-
             mum.  One way to find starting values is to plot data and
             the fitting function on the same graph and change parame-
             ter values and [1mreplot [22muntil reasonable similarity is
             reached.  The same plot is also useful to check whether
             the fit stopped at a minimum with a poor fit.

             Of course, a reasonably good fit is not proof there is not
             a "better" fit (in either a statistical sense, character-
             ized by an improved goodness-of-fit criterion, or a physi-
             cal sense, with a solution more consistent with the
             model.)  Depending on the problem, it may be desirable to
             [1mfit [22mwith various sets of starting values, covering a rea-
             sonable range for each parameter.



             [1m66.7.  Tips[0m


             Here are some tips to keep in mind to get the most out of
             [1mfit[22m.  They're not very organized, so you'll have to read
             them several times until their essence has sunk in.

             The two forms of the [1mvia [22margument to [1mfit [22mserve two largely
             distinct purposes.  The [1mvia "file" [22mform is best used for
             (possibly unattended) batch operation, where you just sup-
             ply the startup values in a file and can later use [1mupdate[0m
             to copy the results back into another (or the same) param-
             eter file.

             The [1mvia var1, var2, ... [22mform is best used interactively,
             where the command history mechanism may be used to edit
             the list of parameters to be fitted or to supply new
             startup values for the next try.  This is particularly
             useful for hard problems, where a direct fit to all param-
             eters at once won't work without good starting values.  To
             find such, you can iterate several times, fitting only
             some of the parameters, until the values are close enough
             to the goal that the final fit to all parameters at once
             will work.

             Make sure that there is no mutual dependency among parame-
             ters of the function you are fitting.  For example, don't
             try to fit a*exp(x+b), because a*exp(x+b)=a*exp(b)*exp(x).
             Instead, fit either a*exp(x) or exp(x+b).

             A technical issue:  the parameters must not be too differ-
             ent in magnitude.  The larger the ratio of the largest and










   GNUPLOT 4.1                                                       82


             the smallest absolute parameter values, the slower the fit
             will converge.  If the ratio is close to or above the
             inverse of the machine floating point precision, it may
             take next to forever to converge, or refuse to converge at
             all.  You will have to adapt your function to avoid this,
             e.g., replace 'parameter' by '1e9*parameter' in the func-
             tion definition, and divide the starting value by 1e9.

             If you can write your function as a linear combination of
             simple functions weighted by the parameters to be fitted,
             by all means do so.  That helps a lot, because the problem
             is no longer nonlinear and should converge with only a
             small number of iterations, perhaps just one.

             Some prescriptions for analysing data, given in practical
             experimentation courses, may have you first fit some func-
             tions to your data, perhaps in a multi-step process of
             accounting for several aspects of the underlying theory
             one by one, and then extract the information you really
             wanted from the fitting parameters of those functions.
             With [1mfit[22m, this may often be done in one step by writing
             the model function directly in terms of the desired param-
             eters.  Transforming data can also quite often be avoided,
             though sometimes at the cost of a more difficult fit prob-
             lem.  If you think this contradicts the previous paragraph
             about simplifying the fit function, you are correct.

             A "singular matrix" message indicates that this implemen-
             tation of the Marquardt-Levenberg algorithm can't calcu-
             late parameter values for the next iteration.  Try differ-
             ent starting values, writing the function in another form,
             or a simpler function.

             Finally, a nice quote from the manual of another fitting
             package (fudgit), that kind of summarizes all these
             issues:  "Nonlinear fitting is an art!"



        [1m67.  Help[0m


        The [1mhelp [22mcommand displays built-in help. To specify information
        on a particular topic use the syntax:

              help {<topic>}

        If <topic> is not specified, a short message is printed about
        [1mgnuplot[22m.  After help for the requested topic is given, a menu
        of subtopics is given; help for a subtopic may be requested by
        typing its name, extending the help request.  After that
        subtopic has been printed, the request may be extended again or
        you may go back one level to the previous topic.  Eventually,










   GNUPLOT 4.1                                                       83


        the [1mgnuplot [22mcommand line will return.

        If a question mark (?) is given as the topic, the list of top-
        ics currently available is printed on the screen.



        [1m68.  History[0m


        [1mhistory [22mcommand lists or saves previous entries in the history
        of the command line editing, or executes an entry.

        Here you find 'usage by examples':

              history               # show the complete history
              history 5             # show last 5 entries in the his-
        tory
              history quiet 5       # show last 5 entries without entry
        numbers
              history "hist.gp"     # write the complete history to
        file hist.gp
              history "hist.gp" append # append the complete history to
        file hist.gp
              history 10 "hist.gp"  # write last 10 commands to file
        hist.gp
              history 10 "|head -5 >>diary.gp" # write 5 history com-
        mands using pipe
              history ?load         # show all history entries starting
        with "load"
              history ?"set c"      # like above, several words
        enclosed in quotes
              hi !reread            # execute last entry starting with
        "reread"
              hist !"set xr"        # like above, several words
        enclosed in quotes
              hi !hi                # guess yourself :-))

        On systems which support a popen function (Unix), the output of
        history can be piped through an external program by starting
        the file name with a '|', as one of the above examples demon-
        strates.



        [1m69.  If[0m


        New syntax:
              if (<condition>) { <command>; <command>
                     <commands>
                     <commands>
              } else {










   GNUPLOT 4.1                                                       84


                     <commands>
              }
        Old syntax:
              if (<condition>) <command-line> [; else if (<condition>)
        ...; else ...]

        This version of gnuplot supports block-structured if/else
        statements. If the keyword [1mif [22mor [1melse [22mis immediately followed
        by an opening "{", then conditional execution applies to all
        statements, possibly on multiple input lines, until a matching
        "}" terminates the block.  If commands may be nested.

        The old single-line if/else syntax is still supported, but can
        not be mixed with the new block-structured syntax.  See [1mif-old[22m.




             [1m69.1.  If-old[0m


             Through gnuplot version 4.4, the scope of the if/else com-
             mands was limited to a single input line. This has been
             replaced by allowing a multi-line clause to be enclosed in
             curly brackets. The old syntax is still honored by itself
             but cannot be used inside a bracketed clause.

             If no opening "{" follows the [1mif [22mkeyword, the command(s)
             in <command-line> will be executed if <condition> is true
             (non-zero) or skipped if <condition> is false (zero).
             Either case will consume commands on the input line until
             the end of the line or an occurrence of [1melse[22m.  Note that
             use of [1m; [22mto allow multiple commands on the same line will
             _not_ end the conditionalized commands.

             Examples:
                   pi=3
                   if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1);
             print pi
             will display:
                   ?Fixing pi!
                   3.14159265358979
             but
                   if (1==2) print "Never see this"; print "Or this
             either"
             will not display anything.

             else:
                   v=0
                   v=v+1; if (v%2) print "2" ; else if (v%3) print "3";
             else print "fred"
             (repeat the last line repeatedly!)











   GNUPLOT 4.1                                                       85


             See [1mreread [22mfor an example of using if and reread together
             to perform a loop.



        [1m70.  Iteration[0m


        The [1mplot[22m, [1msplot[22m, [1mset [22mand [1munset [22mcommands may optionally contain
        an iteration clause.  This has the effect of executing the
        basic command multiple times, each time re-evaluating any
        expressions that make use of the iteration control variable.
        Iteration of arbitrary command sequences can be requested using
        the [1mdo [22mcommand.  Two forms of iteration clause are currently
        supported:

              for [intvar = start:end{:increment}]
              for [stringvar in "A B C D"]

        Examples:

              plot for [filename in "A.dat B.dat C.dat"] filename using
        1:2 with lines
              plot for [basename in "A B C"] basename.".dat" using 1:2
        with lines
              set for [i = 1:10] style line i lc rgb "blue"
              unset for [tag = 100:200] label tag

        Nested iteration is supported:

              set for [i=1:9] for [j=1:9] label i*10+j
        sprintf("%d",i*10+j) at i,j

        See additional documentation for [1mplot iteration[22m, [1mdo[22m.




        [1m71.  Load[0m


        The [1mload [22mcommand executes each line of the specified input file
        as if it had been typed in interactively.  Files created by the
        [1msave [22mcommand can later be [1mload[22med.  Any text file containing
        valid commands can be created and then executed by the [1mload[0m
        command.  Files being [1mload[22med may themselves contain [1mload [22mor
        [1mcall [22mcommands.  See [1mcomments [22mfor information about comments in
        commands.  To [1mload [22mwith arguments, see [1mcall[22m.

        Syntax:
              load "<input-file>"

        The name of the input file must be enclosed in quotes.










   GNUPLOT 4.1                                                       86


        The special filename "-" may be used to [1mload [22mcommands from
        standard input.  This allows a [1mgnuplot [22mcommand file to accept
        some commands from standard input.  Please see help for
        [1mbatch/interactive [22mfor more details.

        On some systems which support a popen function (Unix), the load
        file can be read from a pipe by starting the file name with a
        '<'.

        Examples:
              load 'work.gnu'
              load "func.dat"
              load "< loadfile_generator.sh"

        The [1mload [22mcommand is performed implicitly on any file names
        given as arguments to [1mgnuplot[22m.  These are loaded in the order
        specified, and then [1mgnuplot [22mexits.



        [1m72.  Lower[0m


        Syntax:
              lower {plot_window_nb}

        The [1mlower [22mcommand lowers (opposite to [1mraise[22m) plot window(s)
        associated with the interactive terminal of your gnuplot ses-
        sion, i.e. [1mpm[22m, [1mwin[22m, [1mwxt [22mor [1mx11[22m. It puts the plot window to bot-
        tom in the z-order windows stack of the window manager of your
        desktop.

        As [1mx11 [22mand [1mwxt [22msupport multiple plot windows, then by default
        they lower these windows in descending order of most recently
        created on top to the least recently created on bottom. If a
        plot number is supplied as an optional parameter, only the
        associated plot window will be lowered if it exists.

        The optional parameter is ignored for single plot-window termi-
        nals, i.e. [1mpm [22mand [1mwin[22m.



        [1m73.  Pause[0m


        The [1mpause [22mcommand displays any text associated with the command
        and then waits a specified amount of time or until the carriage
        return is pressed.  [1mpause [22mis especially useful in conjunction
        with [1mload [22mfiles.

        Syntax:
              pause <time> {"<string>"}










   GNUPLOT 4.1                                                       87


              pause mouse {<endcondition>}{, <endcondition>}
        {"<string>"}

        <time> may be any constant or expression.  Choosing -1 will
        wait until a carriage return is hit, zero (0) won't pause at
        all, and a positive number will wait the specified number of
        seconds.  The time is rounded to an integer number of seconds
        if subsecond time resolution is not supported by the given
        platform.  [1mpause 0 [22mis synonymous with [1mprint[22m.

        If the current terminal supports [1mmousing[22m, then [1mpause mouse [22mwill
        terminate on either a mouse click or on ctrl-C.  For all other
        terminals, or if mousing is not active, [1mpause mouse [22mis equiva-
        lent to [1mpause -1[22m.

        If one or more end conditions are given after [1mpause mouse[22m, then
        any one of the conditions will terminate the pause. The possi-
        ble end conditions are [1mkeypress[22m, [1mbutton1[22m, [1mbutton2[22m, [1mbutton3[22m,
        [1mclose[22m, and [1many[22m.  If the pause terminates on a keypress, then
        the ascii value of the key pressed is returned in MOUSE_KEY.
        The character itself is returned as a one character string in
        MOUSE_CHAR. Hotkeys (bind command) are disabled if keypress is
        one of the end conditions.  Zooming is disabled if button3 is
        one of the end conditions.

        In all cases the coordinates of the mouse are returned in vari-
        ables MOUSE_X, MOUSE_Y, MOUSE_X2, MOUSE_Y2.  See [1mmouse vari-[0m
        [1mables[22m.

        Note: Since [1mpause [22mcommunicates with the operating system rather
        than the graphics, it may behave differently with different
        device drivers (depending upon how text and graphics are
        mixed).

        Examples:
              pause -1    # Wait until a carriage return is hit
              pause 3     # Wait three seconds
              pause -1  "Hit return to continue"
              pause 10  "Isn't this pretty?  It's a cubic spline."
              pause mouse "Click any mouse button on selected data
        point"
              pause mouse keypress "Type a letter from A-F in the
        active window"
              pause mouse button1,keypress
              pause mouse any "Any key or button will terminate"

        The variant "pause mouse key" will resume after any keypress in
        the active plot window. If you want to wait for a particular
        key to be pressed, you can use a reread loop such as:

              print "I will resume after you hit the Tab key in the
        plot window"
              load "wait_for_tab"










   GNUPLOT 4.1                                                       88


        File "wait_for_tab" contains the lines

              pause mouse key
              if (MOUSE_KEY != 9) reread




        [1m74.  Plot[0m


        [1mplot [22mis the primary command for drawing plots with [1mgnuplot[22m.  It
        creates plots of functions and data in many, many ways.  [1mplot[0m
        is used to draw 2D functions and data; [1msplot [22mdraws 2D projec-
        tions of 3D surfaces and data.  [1mplot [22mand [1msplot [22moffer many fea-
        tures in common; see [1msplot [22mfor differences.  Note specifically
        that although the [1mbinary <binary list> [22mvariation does work for
        both [1mplot [22mand [1msplot[22m, there are small differences between them.

        Syntax:
              plot {<ranges>}
                   {<iteration>}
                   {<function> | {"<datafile>" {datafile-modifiers}}}
                   {axes <axes>} {<title-spec>} {with <style>}
                   {, {definitions{,}} <function> ...}

        where either a <function> or the name of a data file enclosed
        in quotes is supplied.  A function is a mathematical expression
        or a pair of mathematical expressions in parametric mode.
        Functions may be builtin, user-defined, or provided in the plot
        command itself.  Multiple datafiles and/or functions may be
        plotted in a single command, separated by commas.  See [1mdata[22m,
        [1mfunctions[22m.

        Examples:
              plot sin(x)
              plot sin(x), cos(x)
              plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
              plot "datafile.1" with lines, "datafile.2" with points
              plot [t=1:10] [-pi:pi*2] tan(t), \
                   "data.1" using (tan($2)):($3/$4) smooth csplines \
                            axes x1y2 notitle with lines 5
              plot for [datafile in "spinach.dat broccoli.dat"]
        datafile

        See also [1mshow plot[22m.

















   GNUPLOT 4.1                                                       89


             [1m74.1.  Axes[0m


             There are four possible sets of axes available; the key-
             word <axes> is used to select the axes for which a partic-
             ular line should be scaled.  [1mx1y1 [22mrefers to the axes on
             the bottom and left; [1mx2y2 [22mto those on the top and right;
             [1mx1y2 [22mto those on the bottom and right; and [1mx2y1 [22mto those
             on the top and left.  Ranges specified on the [1mplot [22mcommand
             apply only to the first set of axes (bottom left).



             [1m74.2.  Binary[0m


             BINARY DATA FILES:

             Some earlier versions of [1mgnuplot [22mautomatically detected
             binary data files.  It is now necessary to provide the
             keyword [1mbinary [22mafter the filename.  Adequate details of
             the file format must be given on the command line or
             extracted from the file itself for a supported binary
             [1mfiletype[22m.  In particular, there are two structures for
             binary files,  binary matrix format and binary general
             format.

             The [1mbinary matrix [22mformat contains a two dimensional array
             of 32 bit IEEE float values with an additional column and
             row of coordinate values.  As with ASCII matrix, in the
             [1musing [22mlist, enumeration of the coordinate row constitutes
             column 1, enumeration of the coordinate column constitutes
             column 2, and the array of values constitutes column 3.

             The [1mbinary general [22mformat contains an arbitrary number of
             columns for which information must be specified at the
             command line.  For example, [1marray[22m, [1mrecord[22m, [1mformat [22mand
             [1musing [22mcan indicate the size, format and dimension of data.
             There are a variety of useful commands for skipping file
             headers and changing endianess.  There are a set of com-
             mands for positioning and translating data since often
             coordinates are not part of the file when uniform sampling
             is inherent in the data.  Different from matrix binary or
             ASCII, general binary does not treat the generated columns
             as 1, 2 or 3 in the [1musing [22mlist.  Rather, column 1 begins
             with column 1 of the file, or as specified in the [1mformat[0m
             list.

             There are global default settings for the various binary
             options which may be set using the same syntax as the
             options when used as part of the [1m(s)plot <filename> binary[0m
             [1m... [22mcommand.  This syntax is [1mset datafile binary ...[22m.  The
             general rule is that common command-line specified










   GNUPLOT 4.1                                                       90


             parameters override file-extracted parameters which over-
             ride default parameters.

             [1mBinary matrix [22mis the default binary format when no key-
             words specific to [1mbinary general [22mare given, i.e., [1marray[22m,
             [1mrecord[22m, [1mformat[22m, [1mfiletype[22m.

             General binary data can be entered at the command line via
             the special file name '-'.  However, this is intended for
             use through a pipe where programs can exchange binary
             data, not for keyboards.  There is no "end of record"
             character for binary data.  Gnuplot continues reading from
             a pipe until it has read the number of points declared in
             the [1marray [22mqualifier.  See [1mbinary matrix [22mor [1mbinary general[0m
             for more details.

             The [1mindex [22mkeyword is not supported, since the file format
             allows only one surface per file.  The [1mevery [22mand [1musing[0m
             filters are supported.  [1musing [22moperates as if the data were
             read in the above triplet form.  Binary File Splot Demo.




                  [1m74.2.1.  General[0m


                  General binary data in which format information is
                  not necessarily part of the file can be read by giv-
                  ing further details about the file format at the com-
                  mand line.  Although the syntax is slightly arcane to
                  the casual user, general binary is particularly use-
                  ful for application programs using gnuplot and send-
                  ing large amounts of data.

                  Syntax:
                        plot '<file_name>' {binary <binary list>} ...
                        splot '<file_name>' {binary <binary list>} ...

                  General binary format is activated by keywords in
                  <binary list> pertaining to information about file
                  structure, i.e., [1marray[22m, [1mrecord[22m, [1mformat [22mor [1mfiletype[22m.
                  Otherwise, matrix binary format is assumed.  (See
                  [1mbinary matrix [22mfor more details.)

                  There are some standard file types that may be read
                  for which details about the binary format may be
                  extracted automatically.  (Type [1mshow datafile binary[0m
                  at the command line for a list.)  Otherwise, details
                  must be specified at the command line or set in the
                  defaults.  Keywords are described below.

                  The keyword [1mfiletype [22min <binary list> controls the










   GNUPLOT 4.1                                                       91


                  routine used to read the file, i.e., the format of
                  the data.  For a list of the supported file types,
                  type [1mshow datafile binary filetypes[22m.  If no file type
                  is given, the rule is that traditional gnuplot binary
                  is assumed for [1msplot [22mif the [1mbinary [22mkeyword stands
                  alone.  In all other circumstances, for [1mplot [22mor when
                  one of the <binary list> keywords appears, a raw
                  binary file is assumed whereby the keywords specify
                  the binary format.

                  General binary data files fall into two basic
                  classes, and some files may be of both classes
                  depending upon how they are treated.  There is that
                  class for which uniform sampling is assumed and point
                  coordinates must be generated.  This is the class for
                  which full control via the <binary list> keywords
                  applies.  For this class, the settings precedence is
                  that command line parameters override in-file parame-
                  ters, which override default settings.  The other
                  class is that set of files for which coordinate
                  information is contained within the file or there is
                  possibly a non-uniform sampling such as gnuplot
                  binary.

                  Other than for the unique data files such as gnuplot
                  binary, one should think of binary data as conceptu-
                  ally the same as ASCII data.  Each point has columns
                  of information which are selected via the [1m<using[0m
                  [1mlist> [22massociated with [1musing[22m.  When no [1mformat [22mstring
                  is specified, gnuplot will retrieve a number of
                  binary variables equal to the largest column given in
                  the [1m<using list>[22m.  For example, [1musing 1:3 [22mwill result
                  in three columns being read, of which the second will
                  be ignored.  There are default using lists based upon
                  the typical number of parameters associated with a
                  certain plot type.  For example, [1mwith image [22mhas a
                  default of [1musing 1[22m, while [1mwith rgbimage [22mhas a default
                  of [1musing 1:2:3[22m.  Note that the special characters for
                  [1musing [22mrepresenting point/line/index generally should
                  not be used for binary data.  There are keywords in
                  <binary list> that control this.



                  [1m74.2.2.  Array[0m


                  Describes the sampling array dimensions associated
                  with the binary file.  The coordinates will be gener-
                  ated by gnuplot.  A number must be specified for each
                  dimension of the array.  For example, [1marray=(10,20)[0m
                  means the underlying sampling structure is two-dimen-
                  sional with 10 points along the first (x) dimension










   GNUPLOT 4.1                                                       92


                  and 20 points along the second (y) dimension.  A neg-
                  ative number indicates that data should be read until
                  the end of file.  If there is only one dimension, the
                  parentheses may be omitted.  A colon can be used to
                  separate the dimensions for multiple records.  For
                  example, [1marray=25:35 [22mindicates there are two one-
                  dimensional records in the file.
                        Note:  Gnuplot version 4.2 used the syntax
                  array=128x128 rather than
                               array=(128,128). The older syntax is now
                  deprecated, but may
                               still work if your copy of gnuplot was
                  built to support
                               backwards compatibility.



                  [1m74.2.3.  Record[0m


                  This keyword serves the same function as [1marray[22m, hav-
                  ing the same syntax.  However, [1mrecord [22mcauses gnuplot
                  to not generate coordinate information.  This is for
                  the case where such information may be included in
                  one of the columns of the binary data file.



                  [1m74.2.4.  Skip[0m


                  This keyword allows you to skip sections of a binary
                  file. For instance, if the file contains a 1024 byte
                  header before the start of the data region you would
                  probably want to use
                        plot '<file_name>' binary skip=1024 ...
                  If there are multiple records in the file, you may
                  specify a leading offset for each. For example, to
                  skip 512 bytes before the 1st record and 256 bytes
                  before the second and third records
                        plot '<file_name> binary record=356:356:356
                  skip=512:256:256 ...



                  [1m74.2.5.  Format[0m


                  The default binary format is a float.  For more flex-
                  ibility, the format can include details about vari-
                  able sizes.  For example, [1mformat="%uchar%int%float"[0m
                  associates an unsigned character with the first using
                  column, an int with the second column and a float










   GNUPLOT 4.1                                                       93


                  with the third column.  If the number of size speci-
                  fications is less than the greatest column number,
                  the size is implicitly taken to be similar to the
                  last given variable size.

                  Furthermore, similar to the [1musing [22mspecification, the
                  format can include discarded columns via the [1m* [22mchar-
                  acter and have implicit repetition via a numerical
                  repeat-field.  For example, [1mformat="%*2int%3float"[0m
                  causes gnuplot to discard two ints before reading
                  three floats.  To list variable sizes, type [1mshow[0m
                  [1mdatafile binary datasizes[22m.  There are a group of
                  names that are machine dependent along with their
                  sizes in bytes for the particular compilation.  There
                  is also a group of names which attempt to be machine
                  independent.



                  [1m74.2.6.  Endian[0m


                  Often the endianess of binary data in the file does
                  not agree with the endianess used by the platform on
                  which gnuplot is running.  Several words can direct
                  gnuplot how to arrange bytes.  For example
                  [1mendian=little [22mmeans treat the binary file as having
                  byte significance from least to greatest. The options
                  are

                                little:  least significant to greatest
                  significance
                                   big:  greatest significance to least
                  significance
                               default:  assume file endianess is the
                  same as compiler
                           swap (swab):  Interchange the significance.
                  (If things
                                         don't look right, try this.)

                  Gnuplot can support "middle" ("pdp") endian if it is
                  compiled with that option.



                  [1m74.2.7.  Filetype[0m


                  For some standard binary file formats gnuplot can
                  extract all the necessary information from the file
                  in question.  As an example, "format=edf" will read
                  ESRF Header File format files.  For a list of the
                  currently supported file formats, type [1mshow datafile[0m










   GNUPLOT 4.1                                                       94


                  [1mbinary filetypes[22m.

                  There is a special file type called [1mauto [22mfor which
                  gnuplot will check if the binary file's extension is
                  a quasi-standard extension for a supported format.

                  Command line keywords may be used to override set-
                  tings extracted from the file.  The settings from the
                  file override any defaults.  (See [1mset datafile binary[0m
                  for details.)




                       [1m74.2.7.1.  Avs[0m


                       [1mavs [22mis one of the automatically recognized
                       binary file types for images.  AVS is an
                       extremely simple format, suitable mostly for
                       streaming between applications. It consists of 2
                       longs (xwidth, ywidth) followed by a stream of
                       pixels, each with four bytes of information
                       alpha/red/green/blue.



                       [1m74.2.7.2.  Edf[0m


                       [1medf [22mis one of the automatically recognized
                       binary file types for images.  EDF stands for
                       ESRF Data Format, and it supports both edf and
                       ehf formats (the latter means ESRF Header For-
                       mat).  More information on specifications can be
                       found at

                         http://www.edfplus.info/specs



                       [1m74.2.7.3.  Png[0m


                       If gnuplot was configured to use the libgd
                       library for png/gif/jpeg output, then it can
                       also be used to read these same image types as
                       binary files.  You can use an explicit command
                             plot 'file.png' binary filetype=png
                       Or the file type will be recognized automati-
                       cally from the extension if you have previously
                       requested
                             set datafile binary filetype=auto










   GNUPLOT 4.1                                                       95


                  [1m74.2.8.  Keywords[0m


                  The following keywords apply only when generating
                  coordinates from binary data files.  That is, the
                  control mapping the individual elements of a binary
                  array, matrix, or image to specific x/y/z positions.




                       [1m74.2.8.1.  Scan[0m


                       A great deal of confusion can arise concerning
                       the relationship between how gnuplot scans a
                       binary file and the dimensions seen on the plot.
                       To lessen the confusion, conceptually think of
                       gnuplot _always_ scanning the binary file
                       point/line/plane or fast/medium/slow.  Then this
                       keyword is used to tell gnuplot how to map this
                       scanning convention to the Cartesian convention
                       shown in plots, i.e., x/y/z.  The qualifier for
                       scan is a two or three letter code representing
                       where point is assigned (first letter), line is
                       assigned (second letter), and plane is assigned
                       (third letter).  For example, [1mscan=yx [22mmeans the
                       fastest, point-by-point, increment should be
                       mapped along the Cartesian y dimension and the
                       middle, line-by-line, increment should be mapped
                       along the x dimension.

                       When the plotting mode is [1mplot[22m, the qualifier
                       code can include the two letters x and y.  For
                       [1msplot[22m, it can include the three letters x, y and
                       z.

                       There is nothing restricting the inherent map-
                       ping from point/line/plane to apply only to
                       Cartesian coordinates.  For this reason there
                       are cylindrical coordinate synonyms for the
                       qualifier codes where t (theta), r and z are
                       analogous to the x, y and z of Cartesian coordi-
                       nates.



                       [1m74.2.8.2.  Transpose[0m


                       Shorthand notation for [1mscan=yx [22mor [1mscan=yxz[22m.












   GNUPLOT 4.1                                                       96


                       [1m74.2.8.3.  Dx, dy, dz[0m


                       When gnuplot generates coordinates, it uses the
                       spacing described by these keywords.  For exam-
                       ple [1mdx=10 dy=20 [22mwould mean space samples along
                       the x dimension by 10 and space samples along
                       the y dimension by 20.  [1mdy [22mcannot appear if [1mdx[0m
                       does not appear.  Similarly, [1mdz [22mcannot appear if
                       [1mdy [22mdoes not appear.  If the underlying dimen-
                       sions are greater than the keywords specified,
                       the spacing of the highest dimension given is
                       extended to the other dimensions.  For example,
                       if an image is being read from a file and only
                       [1mdx=3.5 [22mis given gnuplot uses a delta x and delta
                       y of 3.5.

                       The following keywords also apply only when gen-
                       erating coordinates.  However they may also be
                       used with matrix binary files.



                       [1m74.2.8.4.  Flipx, flipy, flipz[0m


                       Sometimes the scanning directions in a binary
                       datafile are not consistent with that assumed by
                       gnuplot.  These keywords can flip the scanning
                       direction along dimensions x, y, z.



                       [1m74.2.8.5.  Origin[0m


                       When gnuplot generates coordinates based upon
                       transposition and flip, it attempts to always
                       position the lower left point in the array at
                       the origin, i.e., the data lies in the first
                       quadrant of a Cartesian system after transpose
                       and flip.

                       To position the array somewhere else on the
                       graph, the [1morigin [22mkeyword directs gnuplot to
                       position the lower left point of the array at a
                       point specified by a tuple.  The tuple should be
                       a double for [1mplot [22mand a triple for [1msplot[22m.  For
                       example, [1morigin=(100,100):(100,200) [22mis for two
                       records in the file and intended for plotting in
                       two dimensions. A second example, [1mori-[0m
                       [1mgin=(0,0,3.5)[22m, is for plotting in three dimen-
                       sions.










   GNUPLOT 4.1                                                       97


                       [1m74.2.8.6.  Center[0m


                       Similar to [1morigin[22m, this keyword will position
                       the array such that its center lies at the point
                       given by the tuple.  For example, [1mcenter=(0,0)[22m.
                       Center does not apply when the size of the array
                       is [1mInf[22m.



                       [1m74.2.8.7.  Rotate[0m


                       The transpose and flip commands provide some
                       flexibility in generating and orienting coordi-
                       nates.  However, for full degrees of freedom, it
                       is possible to apply a rotational vector
                       described by a rotational angle in two dimen-
                       sions.

                       The [1mrotate [22mkeyword applies to the two-dimen-
                       sional plane, whether it be [1mplot [22mor [1msplot[22m.  The
                       rotation is done with respect to the positive
                       angle of the Cartesian plane.

                       The angle can be expressed in radians, radians
                       as a multiple of pi, or degrees.  For example,
                       [1mrotate=1.5708[22m, [1mrotate=0.5pi [22mand [1mrotate=90deg [22mare
                       equivalent.

                       If [1morigin [22mis specified, the rotation is done
                       about the lower left sample point before trans-
                       lation.  Otherwise, the rotation is done about
                       the array [1mcenter[22m.



                       [1m74.2.8.8.  Perpendicular[0m


                       For [1msplot[22m, the concept of a rotational vector is
                       implemented by a triple representing the vector
                       to be oriented normal to the two-dimensional x-y
                       plane.  Naturally, the default is (0,0,1).  Thus
                       specifying both rotate and perpendicular
                       together can orient data myriad ways in three-
                       space.

                       The two-dimensional rotation is done first, fol-
                       lowed by the three-dimensional rotation.  That
                       is, if R' is the rotational 2 x 2 matrix
                       described by an angle, and P is the 3 x 3 matrix










   GNUPLOT 4.1                                                       98


                       projecting (0,0,1) to (xp,yp,zp), let R be con-
                       structed from R' at the upper left sub-matrix, 1
                       at element 3,3 and zeros elsewhere.  Then the
                       matrix formula for translating data is v' = P R
                       v, where v is the 3 x 1 vector of data extracted
                       from the data file.  In cases where the data of
                       the file is inherently not three-dimensional,
                       logical rules are used to place the data in
                       three-space.  (E.g., usually setting the z-
                       dimension value to zero and placing 2D data in
                       the x-y plane.)



             [1m74.3.  Data[0m


             Discrete data contained in a file can be displayed by
             specifying the name of the data file (enclosed in single
             or double quotes) on the [1mplot [22mcommand line.

             Syntax:
                   plot '<file_name>' {binary <binary list>}
                                      {{nonuniform} matrix}
                                      {index <index list> | index
             "<name>"}
                                      {every <every list>}
                                      {thru <thru expression>}
                                      {using <using list>}
                                      {smooth <option>}
                                      {volatile} {noautoscale}

             The modifiers [1mbinary[22m, [1mindex[22m, [1mevery[22m, [1mthru[22m, [1musing[22m, and
             [1msmooth [22mare discussed separately.  In brief, [1mbinary [22mallows
             data entry from a binary file (default is ASCII), [1mindex[0m
             selects which data sets in a multi-data-set file are to be
             plotted, [1mevery [22mspecifies which points within a single data
             set are to be plotted, [1musing [22mdetermines how the columns
             within a single record are to be interpreted ([1mthru [22mis a
             special case of [1musing[22m), and [1msmooth [22mallows for simple
             interpolation and approximation.  ([1msplot [22mhas a similar
             syntax, but does not support the [1msmooth [22mand [1mthru [22moptions.)

             The [1mnoautoscale [22mkeyword means that the points making up
             this plot will be ignored when automatically determining
             axis range limits.

             ASCII DATA FILES:

             Data files should contain at least one data point per
             record ([1musing [22mcan select one data point from the record).
             Records beginning with [1m# [22m(and also with [1m! [22mon VMS) will be
             treated as comments and ignored.  Each data point










   GNUPLOT 4.1                                                       99


             represents an (x,y) pair. For [1mplot[22ms with error bars or
             error bars with lines (see [1mset style errorbars [22mor [1mset[0m
             [1mstyle errorlines[22m), each data point is (x,y,ydelta),
             (x,y,ylow,yhigh), (x,y,xdelta), (x,y,xlow,xhigh), or
             (x,y,xlow,xhigh,ylow,yhigh).

             In all cases, the numbers of each record of a data file
             must be separated by white space (one or more blanks or
             tabs) unless a format specifier is provided by the [1musing[0m
             option. This white space divides each record into columns.
             However, whitespace inside a pair of double quotes is
             ignored when counting columns, so the following datafile
             line has three columns:
                   1.0 "second column" 3.0

             Data may be written in exponential format with the expo-
             nent preceded by the letter e or E.  The fortran exponen-
             tial specifiers d, D, q, and Q may also be used if the
             command [1mset datafile fortran [22mis in effect.

             Only one column (the y value) need be provided.  If x is
             omitted, [1mgnuplot [22mprovides integer values starting at 0.

             In datafiles, blank records (records with no characters
             other than blanks and a newline and/or carriage return)
             are significant.

             Single blank records designate discontinuities in a [1mplot[22m;
             no line will join points separated by a blank records (if
             they are plotted with a line style).

             Two blank records in a row indicate a break between sepa-
             rate data sets.  See [1mindex[22m.

             If autoscaling has been enabled ([1mset autoscale[22m), the axes
             are automatically extended to include all datapoints, with
             a whole number of tic marks if tics are being drawn.  This
             has two consequences: i) For [1msplot[22m, the corner of the sur-
             face may not coincide with the corner of the base.  In
             this case, no vertical line is drawn.  ii) When plotting
             data with the same x range on a dual-axis graph, the x
             coordinates may not coincide if the x2tics are not being
             drawn.  This is because the x axis has been autoextended
             to a whole number of tics, but the x2 axis has not.  The
             following example illustrates the problem:

                   reset; plot '-', '-' axes x2y1
                   1 1
                   19 19
                   e
                   1 1
                   19 19
                   e










   GNUPLOT 4.1                                                      100


             To avoid this, you can use the [1mfixmin[22m/[1mfixmax [22mfeature of
             the [1mset autoscale [22mcommand, which turns off the automatic
             extension of the axis range up to the next tic mark.

             Label coordinates and text can also be read from a data
             file (see [1mlabels[22m).





                  [1m74.3.1.  Every[0m


                  The [1mevery [22mkeyword allows a periodic sampling of a
                  data set to be plotted.

                  In the discussion a "point" is a datum defined by a
                  single record in the file; "block" here will mean the
                  same thing as "datablock" (see [1mglossary[22m).

                  Syntax:
                        plot 'file' every {<point_incr>}
                                            {:{<block_incr>}
                                              {:{<start_point>}
                                                {:{<start_block>}
                                                  {:{<end_point>}
                                                    {:<end_block>}}}}}

                  The data points to be plotted are selected according
                  to a loop from <[1mstart_point[22m> to <[1mend_point[22m> with
                  increment <[1mpoint_incr[22m> and the blocks according to a
                  loop from <[1mstart_block[22m> to <[1mend_block[22m> with increment
                  <[1mblock_incr[22m>.

                  The first datum in each block is numbered '0', as is
                  the first block in the file.

                  Note that records containing unplottable information
                  are counted.

                  Any of the numbers can be omitted; the increments
                  default to unity, the start values to the first point
                  or block, and the end values to the last point or
                  block.  If [1mevery [22mis not specified, all points in all
                  lines are plotted.

                  Examples:
                        every :::3::3    # selects just the fourth
                  block ('0' is first)
                        every :::::9     # selects the first 10 blocks
                        every 2:2        # selects every other point in
                  every other block










   GNUPLOT 4.1                                                      101


                        every ::5::15    # selects points 5 through 15
                  in each block

                  See simple plot demos (simple.dem) , Non-parametric
                  splot demos , and Parametric splot demos .



                  [1m74.3.2.  Example datafile[0m


                  This example plots the data in the file "popula-
                  tion.dat" and a theoretical curve:

                        pop(x) = 103*exp((1965-x)/10)
                        set xrange [1960:1990]
                        plot 'population.dat', pop(x)

                  The file "population.dat" might contain:

                        # Gnu population in Antarctica since 1965
                           1965   103
                           1970   55
                           1975   34
                           1980   24
                           1985   10

                  Binary examples:

                        # Selects two float values (second one
                  implicit) with a float value
                        # discarded between them for an indefinite
                  length of 1D data.
                        plot '<file_name>' binary for-
                  mat="%float%*float" using 1:2 with lines

                        # The data file header contains all details
                  necessary for creating
                        # coordinates from an EDF file.
                        plot '<file_name>' binary filetype=edf with
                  image
                        plot '<file_name>.edf' binary filetype=auto
                  with image

                        # Selects three unsigned characters for compo-
                  nents of a raw RGB image
                        # and flips the y-dimension so that typical
                  image orientation (start
                        # at top left corner) translates to the Carte-
                  sian plane.  Pixel
                        # spacing is given and there are two images in
                  the file.  One of them
                        # is translated via origin.










   GNUPLOT 4.1                                                      102


                        plot '<file_name>' binary
                  array=(512,1024):(1024,512) format='%uchar' \
                             dx=2:1 dy=1:2 origin=(0,0):(1024,1024)
                  flipy u 1:2:3 w rgbimage

                        # Four separate records in which the coordi-
                  nates are part of the
                        # data file.  The file was created with a endi-
                  aness different from
                        # the system on which gnuplot is running.
                        splot '<file_name>' binary record=30:30:29:26
                  endian=swap u 1:2:3

                        # Same input file, but this time we skip the
                  1st and 3rd records
                        splot '<file_name>' binary record=30:26
                  skip=360:348 endian=swap u 1:2:3


                  See also [1mbinary matrix[22m.



                  [1m74.3.3.  Index[0m


                  The [1mindex [22mkeyword allows you to select specific data
                  sets in a multi-data-set file for plotting.

                  Syntax:
                        plot 'file' index { <m>{:<n>{:<p>}} | "<name>"
                  }

                  Data sets are separated by pairs of blank records.
                  [1mindex <m> [22mselects only set <m>; [1mindex <m>:<n> [22mselects
                  sets in the range <m> to <n>; and [1mindex <m>:<n>:<p>[0m
                  selects indices <m>, <m>+<p>, <m>+2<p>, etc., but
                  stopping at <n>.  Following C indexing, the index 0
                  is assigned to the first data set in the file.  Spec-
                  ifying too large an index results in an error mes-
                  sage.  If <p> is specified but <n> is left blank then
                  every <p>-th dataset is read until the end of the
                  file.  If [1mindex [22mis not specified, the entire file is
                  plotted as a single data set.

                  Example:
                        plot 'file' index 4:5

                  For each point in the file, the index value of the
                  data set it appears in is available via the pseudo-
                  column [1mcolumn(-2)[22m.  This leads to an alternative way
                  of distinguishing individual data sets within a file
                  as shown below.  This is more awkward than the [1mindex[0m










   GNUPLOT 4.1                                                      103


                  command if all you are doing is selecting one data
                  set for plotting, but is very useful if you want to
                  assign different properties to each data set.  See
                  [1mpseudocolumns[22m, [1mlc variable[22m.

                  Example:
                        plot 'file' using 1:(column(-2)==4 ? $2 : NaN)
                  # very awkward
                        plot 'file' using 1:2:(column(-2)) linecolor
                  variable # very useful!

                  [1mindex '<name>' [22mselects the data set with name
                  '<name>'.  Names are assigned to data sets in comment
                  lines.  The comment character and leading white space
                  are removed from the comment line.  If the resulting
                  line starts with <name>, the following data set is
                  now named <name> and can be selected.

                  Example:
                        plot 'file' index 'Population'

                  Please note that every comment that starts with
                  <name> will name the following data set.  To avoid
                  problems it may be useful to choose a naming scheme
                  like '== Population ==' or '[Population]'.




                  [1m74.3.4.  Smooth[0m


                  [1mgnuplot [22mincludes a few general-purpose routines for
                  interpolation and approximation of data; these are
                  grouped under the [1msmooth [22moption.  More sophisticated
                  data processing may be performed by preprocessing the
                  data externally or by using [1mfit [22mwith an appropriate
                  model.

                  Syntax:
                        smooth {unique | frequency | cumulative | cnor-
                  mal | kdensity
                                       | csplines | acsplines | bezier
                  | sbezier}

                  [1munique[22m, [1mfrequency[22m, [1mcumulative [22mand [1mcnormal [22mplot the
                  data after making them monotonic.  Each of the other
                  routines uses the data to determine the coefficients
                  of a continuous curve between the endpoints of the
                  data.  This curve is then plotted in the same manner
                  as a function, that is, by finding its value at uni-
                  form intervals along the abscissa (see [1mset samples[22m)
                  and connecting these points with straight line










   GNUPLOT 4.1                                                      104


                  segments (if a line style is chosen).

                  If [1mautoscale [22mis in effect, the ranges will be com-
                  puted such that the plotted curve lies within the
                  borders of the graph.

                  If [1mautoscale [22mis not in effect, and the smooth option
                  is either [1macspline [22mor [1mcspline[22m, the sampling of the
                  generated curve is done across the intersection of
                  the x range covered by the input data and the fixed
                  abscissa range as defined by [1mset xrange[22m.

                  If too few points are available to allow the selected
                  option to be applied, an error message is produced.
                  The minimum number is one for [1munique [22mand [1mfrequency[22m,
                  four for [1macsplines[22m, and three for the others.

                  The [1msmooth [22moptions have no effect on function plots.




                       [1m74.3.4.1.  Acsplines[0m


                       The [1macsplines [22moption approximates the data with
                       a "natural smoothing spline".  After the data
                       are made monotonic in x (see [1msmooth unique[22m), a
                       curve is piecewise constructed from segments of
                       cubic polynomials whose coefficients are found
                       by the weighting the data points; the weights
                       are taken from the third column in the data
                       file.  That default can be modified by the third
                       entry in the [1musing [22mlist, e.g.,
                             plot 'data-file' using 1:2:(1.0) smooth
                       acsplines

                       Qualitatively, the absolute magnitude of the
                       weights determines the number of segments used
                       to construct the curve.  If the weights are
                       large, the effect of each datum is large and the
                       curve approaches that produced by connecting
                       consecutive points with natural cubic splines.
                       If the weights are small, the curve is composed
                       of fewer segments and thus is smoother; the lim-
                       iting case is the single segment produced by a
                       weighted linear least squares fit to all the
                       data.  The smoothing weight can be expressed in
                       terms of errors as a statistical weight for a
                       point divided by a "smoothing factor" for the
                       curve so that (standard) errors in the file can
                       be used as smoothing weights.











   GNUPLOT 4.1                                                      105


                       Example:
                             sw(x,S)=1/(x*x*S)
                             plot 'data_file' using 1:2:(sw($3,100))
                       smooth acsplines



                       [1m74.3.4.2.  Bezier[0m


                       The [1mbezier [22moption approximates the data with a
                       Bezier curve of degree n (the number of data
                       points) that connects the endpoints.



                       [1m74.3.4.3.  Csplines[0m


                       The [1mcsplines [22moption connects consecutive points
                       by natural cubic splines after rendering the
                       data monotonic (see [1msmooth unique[22m).



                       [1m74.3.4.4.  Sbezier[0m


                       The [1msbezier [22moption first renders the data mono-
                       tonic ([1munique[22m) and then applies the [1mbezier [22malgo-
                       rithm.



                       [1m74.3.4.5.  Unique[0m


                       The [1munique [22moption makes the data monotonic in x;
                       points with the same x-value are replaced by a
                       single point having the average y-value.  The
                       resulting points are then connected by straight
                       line segments.



                       [1m74.3.4.6.  Frequency[0m


                       The [1mfrequency [22moption makes the data monotonic in
                       x; points with the same x-value are replaced by
                       a single point having the summed y-values.  The
                       resulting points are then connected by straight
                       line segments.  See also smooth.dem










   GNUPLOT 4.1                                                      106


                       [1m74.3.4.7.  Cumulative[0m


                       The [1mcumulative [22moption makes the data monotonic
                       in x; points with the same x-value are replaced
                       by a single point containing the cumulative sum
                       of y-values of all data points with lower x-val-
                       ues (i.e. to the left of the current data
                       point). This can be used to obtain a cumulative
                       distribution function from data.  See also
                       smooth.dem



                       [1m74.3.4.8.  Cnormal[0m


                       The [1mcnormal [22moption makes the data monotonic in x
                       and normalises the y-values onto the range
                       [0:1].  Points with the same x-value are
                       replaced by a single point containing the cumu-
                       lative sum of y-values of all data points with
                       lower x-values (i.e. to the left of the current
                       data point) divided by the total sum of all y-
                       values. This can be used to obtain a normalised
                       cumulative distribution function from data (use-
                       ful when comparing sets of samples with differ-
                       ing numbers of members).  See also smooth.dem




                       [1m74.3.4.9.  Kdensity[0m


                       The [1mkdensity [22moption is a way to plot a kernel
                       density estimate (which is a smooth histogram)
                       for a random collection of points, using Gaus-
                       sian kernels.  A Gaussian is placed at the loca-
                       tion of each point in the first column and the
                       sum of all these Gaussians is plotted as a func-
                       tion. The value in the second column is taken as
                       weight of the Gaussian. (To obtain a normalized
                       histogram, this should be 1/number-of-points).
                       The value of the third column, if supplied, is
                       taken as the bandwidth for the kernels. If only
                       two columns have been specified, or if the value
                       of the third column is zero or less, gnuplot
                       calculates the bandwidth which would be optimal
                       if the input data was normally distributed.
                       (This will usually be a very conservative, i.e.
                       broad bandwidth.)











   GNUPLOT 4.1                                                      107


                  [1m74.3.5.  Special-filenames[0m


                  There are a few filenames that have a special mean-
                  ing:  '', '-', '+' and '++'.

                  The empty filename '' tells gnuplot to re-use the
                  previous input file in the same plot command. So to
                  plot two columns from the same input file:

                        plot 'filename' using 1:2, '' using 1:3

                  The special filenames '+' and '++' are a mechanism to
                  allow the full range of [1musing [22mspecifiers and plot
                  styles with in-line functions.  Normally a function
                  plot can only have a single y (or z) value associated
                  with each sampled point.  The pseudo-file '+' treats
                  the sampled points as column 1, and allows additional
                  column values to be specified via a [1musing [22mspecifica-
                  tion, just as for a true input file.  The number of
                  samples returned is controlled by [1mset samples[22m.  Exam-
                  ple:

                        plot '+' using ($1):(sin($1)):(sin($1)**2) with
                  filledcurves

                  Similarly the pseudo-file '++' returns 2 columns of
                  data forming a regular grid of [x,y] coordinates with
                  the number of points along x controlled by [1mset sam-[0m
                  [1mples [22mand the number of points along y controlled by
                  [1mset isosamples[22m.  You must set xrange and yrange
                  before plotting '++'.  Examples:

                        splot '++' using 1:2:(sin($1)*sin($2)) with
                  pm3d
                        plot '++' using 1:2:(sin($1)*sin($2)) with
                  image

                  The special filename [1m'-' [22mspecifies that the data are
                  inline; i.e., they follow the command.  Only the data
                  follow the command; [1mplot [22moptions like filters,
                  titles, and line styles remain on the [1mplot [22mcommand
                  line.  This is similar to << in unix shell script,
                  and $DECK in VMS DCL.  The data are entered as though
                  they are being read from a file, one data point per
                  record.  The letter "e" at the start of the first
                  column terminates data entry.  The [1musing [22moption can
                  be applied to these data---using it to filter them
                  through a function might make sense, but selecting
                  columns probably doesn't!

                  [1m'-' [22mis intended for situations where it is useful to
                  have data and commands together, e.g., when [1mgnuplot[0m










   GNUPLOT 4.1                                                      108


                  is run as a sub-process of some front-end applica-
                  tion.  Some of the demos, for example, might use this
                  feature.  While [1mplot [22moptions such as [1mindex [22mand [1mevery[0m
                  are recognized, their use forces you to enter data
                  that won't be used.  For example, while

                        plot '-' index 0, '-' index 1
                        2
                        4
                        6


                        10
                        12
                        14
                        e
                        2
                        4
                        6


                        10
                        12
                        14
                        e

                  does indeed work,

                        plot '-', '-'
                        2
                        4
                        6
                        e
                        10
                        12
                        14
                        e

                  is a lot easier to type.

                  If you use [1m'-' [22mwith [1mreplot[22m, you may need to enter the
                  data more than once.  See [1mreplot[22m, [1mrefresh[22m.

                  A blank filename ('') specifies that the previous
                  filename should be reused.  This can be useful with
                  things like

                        plot 'a/very/long/filename' using 1:2, '' using
                  1:3, '' using 1:4

                  (If you use both [1m'-' [22mand [1m'' [22mon the same [1mplot [22mcommand,
                  you'll need to have two sets of inline data, as in
                  the example above.)










   GNUPLOT 4.1                                                      109


                  On systems with a popen function, the datafile can be
                  piped through a shell command by starting the file
                  name with a '<'.  For example,

                        pop(x) = 103*exp(-x/10)
                        plot "< awk '{print $1-1965, $2}' popula-
                  tion.dat", pop(x)

                  would plot the same information as the first popula-
                  tion example but with years since 1965 as the x axis.
                  If you want to execute this example, you have to
                  delete all comments from the data file above or sub-
                  stitute the following command for the first part of
                  the command above (the part up to the comma):

                        plot "< awk '$0 !~ /^#/ {print $1-1965, $2}'
                  population.dat"

                  While this approach is most flexible, it is possible
                  to achieve simple filtering with the [1musing [22mor [1mthru[0m
                  keywords.

                  On systems with an fdopen() function, data can be
                  read from an arbitrary file descriptor attached to
                  either a file or pipe.  To read from file descriptor
                  [1mn [22muse [1m'<&n'[22m.  This allows you to easily pipe in sev-
                  eral data files in a single call from a POSIX shell:

                        $ gnuplot -p -e "plot '<&3', '<&4'" 3<data-3
                  4<data-4
                        $ ./gnuplot 5< <(myprogram -with -options)
                        gnuplot> plot '<&5'



                  [1m74.3.6.  Thru[0m


                  The [1mthru [22mfunction is provided for backward compati-
                  bility.

                  Syntax:
                        plot 'file' thru f(x)

                  It is equivalent to:

                        plot 'file' using 1:(f($2))

                  While the latter appears more complex, it is much
                  more flexible.  The more natural

                        plot 'file' thru f(y)











   GNUPLOT 4.1                                                      110


                  also works (i.e. you can use y as the dummy vari-
                  able).

                  [1mthru [22mis parsed for [1msplot [22mand [1mfit [22mbut has no effect.



                  [1m74.3.7.  Using[0m


                  The most common datafile modifier is [1musing[22m.  It tells
                  the program which columns of data in the input file
                  are to be plotted.

                  Syntax:
                        plot 'file' using <entry> {:<entry> {:<entry>
                  ...}} {'format'}

                  If a format is specified, it is used to read in each
                  datafile record using the C library 'scanf' function.
                  Otherwise the record is interpreted as consisting of
                  columns (fields) of data separated by whitespace
                  (spaces and/or tabs), but see [1mdatafile separator[22m.

                  Each <entry> may be a simple column number that
                  selects the value from one field of the input file, a
                  string that matches a column label in the first line
                  of a data set, an expression enclosed in parentheses,
                  or a special function not enclosed in parentheses
                  such as xticlabels(2).

                  If the entry is an expression in parentheses, then
                  the function column(N) may be used to indicate the
                  value in column N. That is, column(1) refers to the
                  first item read, column(2) to the second, and so on.
                  The special symbols $1, $2, ... are shorthand for
                  column(1), column(2) ...  The function [1mvalid(N) [22mtests
                  whether the value in the Nth column is a valid num-
                  ber.  If each column of data in the input file con-
                  tains a label in the first row rather than a data
                  value, this label can be used to identify the column
                  on input and/or in the plot legend. The column()
                  function can be used to select an input column by
                  label rather than by column number.  For example, if
                  the data file contains
                        Height    Weight    Age
                        val1      val1      val1
                        ...       ...       ...
                  then the following plot commands are all equivalent
                        plot 'datafile' using 3:1, '' using 3:2
                        plot 'datafile' using (column("Age")):(col-
                  umn(1)), \
                                     '' using










   GNUPLOT 4.1                                                      111


                  (column("Age")):(column(2))
                        plot 'datafile' using "Age":"Height", '' using
                  "Age":"Weight"

                  The full string must match. Comparison is case-sensi-
                  tive.  To use the column labels in the plot legend,
                  use [1mset key autotitle columnhead[22m.

                  In addition to the actual columns 1...N in the input
                  data file, gnuplot presents data from several
                  "pseudo-columns" that hold bookkeeping information.
                  E.g. $0 or column(0) returns the sequence number of
                  this data record within a dataset.  Please see [1mpseu-[0m
                  [1mdocolumns[22m.

                  An empty <entry> will default to its order in the
                  list of entries.  For example, [1musing ::4 [22mis inter-
                  preted as [1musing 1:2:4[22m.

                  If the [1musing [22mlist has only a single entry, that
                  <entry> will be used for y and the data point number
                  (pseudo-column $0) is used for x; for example, "[1mplot[0m
                  [1m'file' using 1[22m" is identical to "[1mplot 'file' using[0m
                  [1m0:1[22m".  If the [1musing [22mlist has two entries, these will
                  be used for x and y.  See [1mset style [22mand [1mfit [22mfor
                  details about plotting styles that make use of data
                  from additional columns of input.

                  'scanf' accepts several numerical specifications but
                  [1mgnuplot [22mrequires all inputs to be double-precision
                  floating-point variables, so "%lf" is essentially the
                  only permissible specifier.  A format string given by
                  the user must contain at least one such input speci-
                  fier, and no more than seven of them.  'scanf'
                  expects to see white space---a blank, tab ("\t"),
                  newline ("\n"), or formfeed ("\f")---between numbers;
                  anything else in the input stream must be explicitly
                  skipped.

                  Note that the use of "\t", "\n", or "\f" requires use
                  of double-quotes rather than single-quotes.




                       [1m74.3.7.1.  Using_examples[0m


                       This creates a plot of the sum of the 2nd and
                       3rd data against the first: The format string
                       specifies comma- rather than space-separated
                       columns.  The same result could be achieved by
                       specifying [1mset datafile separator ","[22m.










   GNUPLOT 4.1                                                      112


                             plot 'file' using 1:($2+$3) '%lf,%lf,%lf'

                       In this example the data are read from the file
                       "MyData" using a more complicated format:
                             plot 'MyData' using "%*lf%lf%*20[^\n]%lf"

                       The meaning of this format is:

                             %*lf        ignore a number
                             %lf         read a double-precision number
                       (x by default)
                             %*20[^\n]   ignore 20 non-newline charac-
                       ters
                             %lf         read a double-precision number
                       (y by default)

                       One trick is to use the ternary [1m?: [22moperator to
                       filter data:

                             plot 'file' using 1:($3>10 ? $2 : 1/0)

                       which plots the datum in column two against that
                       in column one provided the datum in column three
                       exceeds ten.  [1m1/0 [22mis undefined; [1mgnuplot [22mquietly
                       ignores undefined points, so unsuitable points
                       are suppressed.  Or you can use the pre-defined
                       variable NaN to achieve the same result.

                       In fact, you can use a constant expression for
                       the column number, provided it doesn't start
                       with an opening parenthesis; constructs like
                       [1musing 0+(complicated expression) [22mcan be used.
                       The crucial point is that the expression is
                       evaluated once if it doesn't start with a left
                       parenthesis, or once for each data point read if
                       it does.

                       If timeseries data are being used, the time can
                       span multiple columns.  The starting column
                       should be specified.  Note that the spaces
                       within the time must be included when calculat-
                       ing starting columns for other data.  E.g., if
                       the first element on a line is a time with an
                       embedded space, the y value should be specified
                       as column three.

                       It should be noted that [1mplot 'file'[22m, [1mplot 'file'[0m
                       [1musing 1:2[22m, and [1mplot 'file' using ($1):($2) [22mcan
                       be subtly different: 1) if [1mfile [22mhas some lines
                       with one column and some with two, the first
                       will invent x values when they are missing, the
                       second will quietly ignore the lines with one
                       column, and the third will store an undefined










   GNUPLOT 4.1                                                      113


                       value for lines with one point (so that in a
                       plot with lines, no line joins points across the
                       bad point); 2) if a line contains text at the
                       first column, the first will abort the plot on
                       an error, but the second and third should qui-
                       etly skip the garbage.

                       In fact, it is often possible to plot a file
                       with lots of lines of garbage at the top simply
                       by specifying

                             plot 'file' using 1:2

                       However, if you want to leave text in your data
                       files, it is safer to put the comment character
                       (#) in the first column of the text lines.



                       [1m74.3.7.2.  Pseudocolumns[0m


                       Expressions in the [1musing [22mclause of a plot state-
                       ment can refer to additional bookkeeping values
                       in addition to the actual data values contained
                       in the input file. These are contained in "pseu-
                       docolumns".
                             column(0)   The sequential order of each
                       point within a data set.
                                         The counter starts at 0 and is
                       reset by two sequential blank
                                         records.  The shorthand form
                       $0 is available.
                             column(-1)  This counter starts at 0 and
                       is reset by a single blank line.
                                         This corresponds to the data
                       line in array or grid data.
                             column(-2)  The index number of the cur-
                       rent data set within a file that
                                         contains multiple data sets.
                       See `index`.



                       [1m74.3.7.3.  Xticlabels[0m


                       Axis tick labels can be generated via a string
                       function, usually taking a data column as an
                       argument. The simplest form uses the data column
                       itself as a string. That is,  xticlabels(N) is
                       shorthand for xticlabels(stringcolumn(N)).  This
                       example uses the contents of column 3 as x-axis










   GNUPLOT 4.1                                                      114


                       tick labels.

                             plot 'datafile' using <xcol>:<ycol>:xti-
                       clabels(3) with <plotstyle>

                       Axis tick labels may be generated for any of the
                       plot axes: x x2 y y2 z.  The [1mticlabels(<label-[0m
                       [1mcol>) [22mspecifiers must come after all of the data
                       coordinate specifiers in the [1musing [22mportion of
                       the command.  For each data point which has a
                       valid set of X,Y[,Z] coordinates, the string
                       value given to xticlabels() is added to the list
                       of xtic labels at the same X coordinate as the
                       point it belongs to. [1mxticlabels() [22mmay be short-
                       ened to [1mxtic() [22mand so on.

                       Example:

                             splot "data" using
                       2:4:6:xtic(1):ytic(3):ztic(6)

                       In this example the x and y axis tic labels are
                       taken from different columns than the x and y
                       coordinate values. The z axis tics, however, are
                       generated from the z coordinate of the corre-
                       sponding point.

                       Example:

                             plot "data" using 1:2:xtic( $3 > 10. ? "A"
                       : "B" )

                       This example shows the use of a string-valued
                       function to generate x-axis tick labels. Each
                       point in the data file generates a tick mark on
                       x labeled either "A" or "B" depending on the
                       value in column 3.



                       [1m74.3.7.4.  X2ticlabels[0m


                       See [1mplot using xticlabels[22m.



                       [1m74.3.7.5.  Yticlabels[0m


                       See [1mplot using xticlabels[22m.












   GNUPLOT 4.1                                                      115


                       [1m74.3.7.6.  Y2ticlabels[0m


                       See [1mplot using xticlabels[22m.



                       [1m74.3.7.7.  Zticlabels[0m


                       See [1mplot using xticlabels[22m.



                  [1m74.3.8.  Volatile[0m


                  The [1mvolatile [22mkeyword in a plot command indicates that
                  the data previously read from the input stream or
                  file may not be available for re-reading.  This tells
                  the program to use [1mrefresh [22mrather than [1mreplot [22mcom-
                  mands whenever possible.  See [1mrefresh[22m.



             [1m74.4.  Errorbars[0m


             Error bars are supported for 2D data file plots by reading
             one to four additional columns (or [1musing [22mentries); these
             additional values are used in different ways by the vari-
             ous errorbar styles.

             In the default situation, [1mgnuplot [22mexpects to see three,
             four, or six numbers on each line of the data
             file---either

                   (x, y, ydelta),
                   (x, y, ylow, yhigh),
                   (x, y, xdelta),
                   (x, y, xlow, xhigh),
                   (x, y, xdelta, ydelta), or
                   (x, y, xlow, xhigh, ylow, yhigh).

             The x coordinate must be specified.  The order of the num-
             bers must be exactly as given above, though the [1musing[0m
             qualifier can manipulate the order and provide values for
             missing columns.  For example,

                   plot 'file' with errorbars
                   plot 'file' using 1:2:(sqrt($1)) with xerrorbars
                   plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyer-
             rorbars










   GNUPLOT 4.1                                                      116


             The last example is for a file containing an unsupported
             combination of relative x and absolute y errors.  The
             [1musing [22mentry generates absolute x min and max from the rel-
             ative error.

             The y error bar is a vertical line plotted from (x, ylow)
             to (x, yhigh). If ydelta is specified instead of ylow and
             yhigh, ylow = y - ydelta and yhigh = y + ydelta are
             derived. If there are only two numbers on the record,
             yhigh and ylow are both set to y. The x error bar is a
             horizontal line computed in the same fashion. To get lines
             plotted between the data points, [1mplot [22mthe data file twice,
             once with errorbars and once with lines (but remember to
             use the [1mnotitle [22moption on one to avoid two entries in the
             key). Alternately, use the errorlines command (see [1merror-[0m
             [1mlines[22m).

             The error bars have crossbars at each end unless [1mset bars[0m
             is used (see [1mset bars [22mfor details).

             If autoscaling is on, the ranges will be adjusted to
             include the error bars.

             See also errorbar demos.

             See [1mplot using[22m, [1mplot with[22m, and [1mset style [22mfor more informa-
             tion.



             [1m74.5.  Errorlines[0m


             Lines with error bars are supported for 2D data file plots
             by reading one to four additional columns (or [1musing[0m
             entries); these additional values are used in different
             ways by the various errorlines styles.

             In the default situation, [1mgnuplot [22mexpects to see three,
             four, or six numbers on each line of the data
             file---either

                   (x, y, ydelta),
                   (x, y, ylow, yhigh),
                   (x, y, xdelta),
                   (x, y, xlow, xhigh),
                   (x, y, xdelta, ydelta), or
                   (x, y, xlow, xhigh, ylow, yhigh).

             The x coordinate must be specified. The order of the num-
             bers must be exactly as given above, though the [1musing[0m
             qualifier can manipulate the order and provide values for
             missing columns. For example,










   GNUPLOT 4.1                                                      117


                   plot 'file' with errorlines
                   plot 'file' using 1:2:(sqrt($1)) with xerrorlines
                   plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyer-
             rorlines

             The last example is for a file containing an unsupported
             combination of relative x and absolute y errors. The [1musing[0m
             entry generates absolute x min and max from the relative
             error.

             The y error bar is a vertical line plotted from (x, ylow)
             to (x, yhigh). If ydelta is specified instead of ylow and
             yhigh, ylow = y - ydelta and yhigh = y + ydelta are
             derived. If there are only two numbers on the record,
             yhigh and ylow are both set to y. The x error bar is a
             horizontal line computed in the same fashion.

             The error bars have crossbars at each end unless [1mset bars[0m
             is used (see [1mset bars [22mfor details).

             If autoscaling is on, the ranges will be adjusted to
             include the error bars.

             See [1mplot using[22m, [1mplot with[22m, and [1mset style [22mfor more informa-
             tion.



             [1m74.6.  Functions[0m


             Built-in or user-defined functions can be displayed by the
             [1mplot [22mand [1msplot [22mcommands in addition to, or instead of,
             data read from a file. The requested function is evaluated
             by sampling at regular intervals spanning the independent
             axis range[s]. See [1mset samples [22mand [1mset isosamples[22m.  Exam-
             ple:
                   approx(ang) = ang - ang**3 / (3*2)
                   plot sin(x) title "sin(x)", approx(x) title "approx-
             imation"

             To set a default plot style for functions, see [1mset style[0m
             [1mfunction[22m.  For information on built-in functions, see
             [1mexpressions functions[22m.  For information on defining your
             own functions, see [1muser-defined[22m.



             [1m74.7.  Parametric[0m


             When in parametric mode ([1mset parametric[22m) mathematical
             expressions must be given in pairs for [1mplot [22mand in










   GNUPLOT 4.1                                                      118


             triplets for [1msplot[22m.

             Examples:
                   plot sin(t),t**2
                   splot cos(u)*cos(v),cos(u)*sin(v),sin(u)

             Data files are plotted as before, except any preceding
             parametric function must be fully specified before a data
             file is given as a plot.  In other words, the x parametric
             function ([1msin(t) [22mabove) and the y parametric function
             ([1mt**2 [22mabove) must not be interrupted with any modifiers or
             data functions; doing so will generate a syntax error
             stating that the parametric function is not fully speci-
             fied.

             Other modifiers, such as [1mwith [22mand [1mtitle[22m, may be specified
             only after the parametric function has been completed:

                   plot sin(t),t**2 title 'Parametric example' with
             linespoints

             See also Parametric Mode Demos.



             [1m74.8.  Ranges[0m


             The optional axis ranges at the start of a plot command
             specify the region of the graph that will be displayed.
             These override any ranges established by a previous [1mset[0m
             [1mrange [22mstatement.

             Syntax:
                   [{<dummy-var>=}{{<min>}:{<max>}}]
                   [{{<min>}:{<max>}}]

             The first form applies to the independent variable ([1mxrange[0m
             or [1mtrange[22m, if in parametric mode).  The second form
             applies to the dependent variable [1myrange [22m(and [1mxrange[22m, too,
             if in parametric mode).  <dummy-var> is a new name for the
             independent variable.  (The defaults may be changed with
             [1mset dummy[22m.)  The optional <min> and <max> terms can be
             constant expressions or *.

             In non-parametric mode, the order in which ranges must be
             given is [1mxrange [22mand [1myrange[22m.

             In parametric mode, the order for the [1mplot [22mcommand is
             [1mtrange[22m, [1mxrange[22m, and [1myrange[22m.  The following [1mplot [22mcommand
             shows setting the [1mtrange [22mto [-pi:pi], the [1mxrange [22mto
             [-1.3:1.3] and the [1myrange [22mto [-1:1] for the duration of
             the graph:










   GNUPLOT 4.1                                                      119


                   plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2

             Note that the x2range and y2range cannot be specified
             here---[1mset x2range [22mand [1mset y2range [22mmust be used.

             Ranges are interpreted in the order listed above for the
             appropriate mode.  Once all those needed are specified, no
             further ones must be listed, but unneeded ones cannot be
             skipped---use an empty range [1m[] [22mas a placeholder.

             [1m* [22mcan be used to allow autoscaling of either of min and
             max.  See also [1mset autoscale[22m.

             Ranges specified on the [1mplot [22mor [1msplot [22mcommand line affect
             only that graph; use the [1mset xrange[22m, [1mset yrange[22m, etc.,
             commands to change the default ranges for future graphs.

             With time data, you must provide the range (in the same
             manner as the time appears in the datafile) within quotes.
             [1mgnuplot [22muses the [1mtimefmt [22mstring to read the value---see
             [1mset timefmt[22m.

             Examples:

             This uses the current ranges:
                   plot cos(x)

             This sets the x range only:
                   plot [-10:30] sin(pi*x)/(pi*x)

             This is the same, but uses t as the dummy-variable:
                   plot [t = -10 :30]  sin(pi*t)/(pi*t)

             This sets both the x and y ranges:
                   plot [-pi:pi] [-3:3]  tan(x), 1/x

             This sets only the y range, and turns off autoscaling on
             both axes:
                   plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)

             This sets xmax and ymin only:
                   plot [:200] [-pi:]  exp(sin(x))

             This sets the x range for a timeseries:
                   set timefmt "%d/%m/%y %H:%M"
                   plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'

















   GNUPLOT 4.1                                                      120


             [1m74.9.  Iteration[0m


             If many similar files or functions are to be plotted
             together, it may be convenient to do so by iterating over
             a shared plot command.

             Syntax:
                   plot for [<variable> = <start> : <end> {:<incre-
             ment>}]
                   plot for [<variable> in "string of words"]

             The scope of an iteration ends at the next comma or the
             end of the command, whichever comes first.  Iteration can
             not be nested.

             This will plot one curve, sin(3x), because iteration ends
             at the comma
                   plot for [i=1:3] j=i, sin(j*x)
             This will plot three curves because there is no comma
             after the definition of j
                   plot for [i=1:3] j=i sin(j*x)

             Example:
                   plot for [dataset in "apples bananas"] dataset."dat"
             title dataset

             In this example iteration is used both to generate a file
             name and a corresponding title.

             Example:
                   file(n) = sprintf("dataset_%d.dat",n)
                   splot for [i=1:10] file(i) title sprintf("dataset
             %d",i)

             This example defines a string-valued function that gener-
             ates file names, and plots ten such files together. The
             iteration variable ('i' in this example) is treated as an
             integer, and may be used more than once.

             Example:
                   set key left
                   plot for [n=1:4] x**n sprintf("%d",n)

             This example plots a family of functions.

             Example:
                   list = "apple banana cabbage daikon eggplant"
                   item(n) = word(list,n)
                   plot for [i=1:words(list)] item[i].".dat" title
             item(i)
                   list = "new stuff"
                   replot










   GNUPLOT 4.1                                                      121


             This example steps through a list and plots once per item.
             Because the items are retrieved dynamically, you can
             change the list and then replot.

             Example:
                   list = "apple banana cabbage daikon eggplant"
                   plot for [i in list] i.".dat" title i
                   list = "new stuff"
                   replot

             This is example does exactly the same thing as the previ-
             ous example, but uses the string iterator form of the com-
             mand rather than an integer iterator.




             [1m74.10.  Title[0m


             By default each plot is listed in the key by the corre-
             sponding function or file name. You can give an explicit
             plot title instead using the [1mtitle [22moption.

             Syntax:
                   title <text> | notitle [<ignored text>]
                   title columnheader | title columnheader(N)

             where <text> is a quoted string or an expression that
             evaluates to a string.  The quotes will not be shown in
             the key.

             There is also an option that will interpret the first
             entry in a column of input data (i.e. the column header)
             as a text field, and use it as the key title.  See [1mdatas-[0m
             [1mtrings[22m.  This can be made the default by specifying [1mset[0m
             [1mkey autotitle columnhead[22m.

             The line title and sample can be omitted from the key by
             using the keyword [1mnotitle[22m.  A null title ([1mtitle ''[22m) is
             equivalent to [1mnotitle[22m.  If only the sample is wanted, use
             one or more blanks ([1mtitle ' '[22m).  If [1mnotitle [22mis followed by
             a string this string is ignored.

             If [1mkey autotitles [22mis set (which is the default) and nei-
             ther [1mtitle [22mnor [1mnotitle [22mare specified the line title is the
             function name or the file name as it appears on the [1mplot[0m
             command.  If it is a file name, any datafile modifiers
             specified will be included in the default title.

             The layout of the key itself (position, title justifica-
             tion, etc.) can be controlled by [1mset key[22m.  Please see [1mset[0m
             [1mkey [22mfor details.










   GNUPLOT 4.1                                                      122


             Examples:

             This plots y=x with the title 'x':
                   plot x

             This plots x squared with title "x^2" and file "data.1"
             with title "measured data":
                   plot x**2 title "x^2", 'data.1' t "measured data"

             This puts an untitled circular border around a polar
             graph:
                   set polar; plot my_function(t), 1 notitle

             Plot multiple columns of data, each of which contains its
             own title in the file
                   plot for [i=1:4] 'data' using i title columnhead




             [1m74.11.  With[0m


             Functions and data may be displayed in one of a large num-
             ber of styles.  The [1mwith [22mkeyword provides the means of
             selection.

             Syntax:
                   with <style> { {linestyle | ls <line_style>}
                                  | {{linetype  | lt <line_type>}
                                     {linewidth | lw <line_width>}
                                     {linecolor | lc <colorspec>}
                                     {pointtype | pt <point_type>}
                                     {pointsize | ps <point_size>}
                                     {fill | fs <fillstyle>}
                                     {nohidden3d} {nocontours} {nosur-
             face}
                                     {palette}}
                                }


             where <style> is one of

                  lines        dots       steps     errorbars     xer-
             rorbar    xyerrorlines
                  points       impulses   fsteps    errorlines    xer-
             rorlines  yerrorbars
                  linespoints  labels     histeps   financebars   xyer-
             rorbars  yerrorlines
                                                    vectors
             or
                   boxes            candlesticks   image      circles
                   boxerrorbars     filledcurves   rgbimage   ellipses










   GNUPLOT 4.1                                                      123


                   boxxyerrorbars   histograms     rgbalpha   pm3d
                   boxplot

             The first group of styles have associated line, point, and
             text properties.  The second group of styles also have
             fill properties.  See [1mfillstyle[22m.  Some styles have further
             sub-styles.  See [1mplotting styles [22mfor details of each.

             A default style may be chosen by [1mset style function [22mand
             [1mset style data[22m.

             By default, each function and data file will use a differ-
             ent line type and point type, up to the maximum number of
             available types.  All terminal drivers support at least
             six different point types, and re-use them, in order, if
             more are required.  To see the complete set of line and
             point types available for the current terminal, type [1mtest[22m.

             If you wish to choose the line or point type for a single
             plot, <line_type> and <point_type> may be specified.
             These are positive integer constants (or expressions) that
             specify the line type and point type to be used for the
             plot.  Use [1mtest [22mto display the types available for your
             terminal.

             You may also scale the line width and point size for a
             plot by using <line_width> and <point_size>, which are
             specified relative to the default values for each termi-
             nal.  The pointsize may also be altered globally---see [1mset[0m
             [1mpointsize [22mfor details.  But note that both <point_size> as
             set here and  as set by [1mset pointsize [22mmultiply the default
             point size---their effects are  not cumulative.  That is,
             [1mset pointsize 2; plot x w p ps 3 [22mwill use points three
             times default size, not six.

             It is also possible to specify [1mpointsize variable [22meither
             as part of a line style or for an individual plot. In this
             case one extra column of input is required, i.e. 3 columns
             for a 2D plot and 4 columns for a 3D splot. The size of
             each individual point is determined by multiplying the
             global pointsize by the value read from the data file.

             If you have defined specific line type/width and point
             type/size combinations with [1mset style line[22m, one of these
             may be selected by setting <line_style> to the index of
             the desired style.

             If gnuplot was built with [1mpm3d [22msupport, the special key-
             word [1mpalette [22mis allowed for smooth color change of lines,
             points and dots in [1msplots[22m. The color is chosen from a
             smooth palette which was set previously with the command
             [1mset palette[22m. The color value corresponds to the z-value of
             the point coordinates or to the color coordinate if










   GNUPLOT 4.1                                                      124


             specified by the 4th parameter in [1musing[22m. Both 2D and 3D
             plots ([1mplot [22mand [1msplot [22mcommands) can use palette colors as
             specified by either their fractional value or the corre-
             sponding value mapped to the colorbox range.  A palette
             color value can also be read from an explicitly specified
             input column in the [1musing [22mspecifier.  See [1mcolors[22m, [1mset[0m
             [1mpalette[22m, [1mlinetype[22m.

             The keyword [1mnohidden3d [22mapplies only to plots made with the
             [1msplot [22mcommand.  Normally the global option [1mset hidden3d[0m
             applies to all plots in the graph.  You can attach the
             [1mnohidden3d [22moption to any individual plots that you want to
             exclude from the hidden3d processing.  The individual ele-
             ments other than surfaces (i.e. lines, dots, labels, ...)
             of a plot marked [1mnohidden3d [22mwill all be drawn, even if
             they would normally be obscured by other plot elements.

             Similarly, the keyword [1mnocontours [22mwill turn off contouring
             for an individual plot even if the global property [1mset[0m
             [1mcontour [22mis active.

             Similarly, the keyword [1mnosurface [22mwill turn off the 3D sur-
             face for an individual plot even if the global property
             [1mset surface [22mis active.

             The keywords may be abbreviated as indicated.

             Note that the [1mlinewidth[22m, [1mpointsize [22mand [1mpalette [22moptions are
             not supported by all terminals.

             Examples:

             This plots sin(x) with impulses:
                   plot sin(x) with impulses

             This plots x with points, x**2 with the default:
                   plot x w points, x**2

             This plots tan(x) with the default function style, file
             "data.1" with lines:
                   plot [ ] [-2:5] tan(x), 'data.1' with l

             This plots "leastsq.dat" with impulses:
                   plot 'leastsq.dat' w i

             This plots the data file "population" with boxes:
                   plot 'population' with boxes

             This plots "exper.dat" with errorbars and lines connecting
             the points (errorbars require three or four columns):
                   plot 'exper.dat' w lines, 'exper.dat' notitle w
             errorbars











   GNUPLOT 4.1                                                      125


             Another way to plot "exper.dat" with errorlines (errorbars
             require three or four columns):
                   plot 'exper.dat' w errorlines

             This plots sin(x) and cos(x) with linespoints, using the
             same line type but different point types:
                   plot sin(x) with linesp lt 1 pt 3, cos(x) with
             linesp lt 1 pt 4

             This plots file "data" with points of type 3 and twice
             usual size:
                   plot 'data' with points pointtype 3 pointsize 2

             This plots file "data" with variable pointsize read from
             column 4
                   plot 'data' using 1:2:4 with points pt 5 pointsize
             variable

             This plots two data sets with lines differing only by
             weight:
                   plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l
             lt 2 lw 1

             This plots filled curve of x*x and a color stripe:
                   plot x*x with filledcurve closed, 40 with filled-
             curve y1=10

             This plots x*x and a color box:
                   plot x*x, (x>=-5 && x<=5 ? 40 : 1/0) with filled-
             curve y1=10 lt 8

             This plots a surface with color lines:
                   splot x*x-y*y with line palette

             This plots two color surfaces at different altitudes:
                   splot x*x-y*y with pm3d, x*x+y*y with pm3d at t




        [1m75.  Print[0m


        The [1mprint [22mcommand prints the value of <expression> to the
        screen.  It is synonymous with [1mpause 0[22m.  <expression> may be
        anything that [1mgnuplot [22mcan evaluate that produces a number, or
        it can be a string.

        Syntax:
              print <expression> {, <expression>, ...}

        See [1mexpressions[22m.  The output file can be set with [1mset print[22m.











   GNUPLOT 4.1                                                      126


        [1m76.  Pwd[0m


        The [1mpwd [22mcommand prints the name of the working directory to the
        screen.

        Note that if you wish to store the current directory into a
        string variable or use it in string expressions, then you can
        use variable GPVAL_PWD, see [1mshow variables all[22m.



        [1m77.  Quit[0m


        The [1mexit [22mand [1mquit [22mcommands and END-OF-FILE character will exit
        [1mgnuplot[22m.  Each of these commands will clear the output device
        (as does the [1mclear [22mcommand) before exiting.



        [1m78.  Raise[0m


        Syntax:
              raise {plot_window_nb}

        The [1mraise [22mcommand raises (opposite to [1mlower[22m) plot window(s)
        associated with the interactive terminal of your gnuplot ses-
        sion, i.e. [1mpm[22m, [1mwin[22m, [1mwxt [22mor [1mx11[22m. It puts the plot window to
        front (top) in the z-order windows stack of the window manager
        of your desktop.

        As [1mx11 [22mand [1mwxt [22msupport multiple plot windows, then by default
        they raise these windows in descending order of most recently
        created on top to the least recently created on bottom. If a
        plot number is supplied as an optional parameter, only the
        associated plot window will be raised if it exists.

        The optional parameter is ignored for single plot-windows ter-
        minal, i.e. [1mpm [22mand [1mwin[22m.

        If the window is not raised under X11, then perhaps the plot
        window is running in a different X11 session (telnet or ssh
        session, for example), or perhaps raising is blocked by your
        window manager policy setting.



        [1m79.  Refresh[0m













   GNUPLOT 4.1                                                      127


        The [1mrefresh [22mcommand is similar to [1mreplot[22m, with two major dif-
        ferences.  [1mrefresh [22mreformats and redraws the current plot using
        the data already read in. This means that you can use [1mrefresh[0m
        for plots with in-line data (pseudo-device '-') and for plots
        from datafiles whose contents are volatile.  You cannot use the
        [1mrefresh [22mcommand to add new data to an existing plot.

        Mousing operations, in particular zoom and unzoom, will use
        [1mrefresh [22mrather than [1mreplot [22mif appropriate.  Example:

              plot 'datafile' volatile with lines, '-' with labels
              100 200 "Special point"
              e
              # Various mousing operations go here
              set title "Zoomed in view"
              set term post
              set output 'zoom.ps'
              refresh




        [1m80.  Replot[0m


        The [1mreplot [22mcommand without arguments repeats the last [1mplot [22mor
        [1msplot [22mcommand.  This can be useful for viewing a plot with dif-
        ferent [1mset [22moptions, or when generating the same plot for sev-
        eral devices.

        Arguments specified after a [1mreplot [22mcommand will be added onto
        the last [1mplot [22mor [1msplot [22mcommand (with an implied ',' separator)
        before it is repeated.  [1mreplot [22maccepts the same arguments as
        the [1mplot [22mand [1msplot [22mcommands except that ranges cannot be speci-
        fied.  Thus you can use [1mreplot [22mto plot a function against the
        second axes if the previous command was [1mplot [22mbut not if it was
        [1msplot[22m.

        N.B.---use of

              plot '-' ; ... ; replot

        is not recommended, because it will require that you type in
        the data all over again.  In most cases you can use the [1mrefresh[0m
        command instead, which will redraw the plot using the data pre-
        viously read in.

        Note that [1mreplot [22mdoes not work in [1mmultiplot [22mmode, since it
        reproduces only the last plot rather than the entire screen.

        See also [1mcommand-line-editing [22mfor ways to edit the last [1mplot[0m
        ([1msplot[22m) command.











   GNUPLOT 4.1                                                      128


        See also [1mshow plot [22mto show the whole current plotting command,
        and the possibility to copy it into the [1mhistory[22m.



        [1m81.  Reread[0m


        The [1mreread [22mcommand causes the current [1mgnuplot [22mcommand file, as
        specified by a [1mload [22mcommand or on the command line, to be reset
        to its starting point before further commands are read from it.
        This essentially implements an endless loop of the commands
        from the beginning of the command file to the [1mreread [22mcommand.
        (But this is not necessarily a disaster---[1mreread [22mcan be very
        useful when used in conjunction with [1mif[22m.)  The [1mreread [22mcommand
        has no effect if input from standard input.

        Examples:

        Suppose the file "looper" contains the commands
              a=a+1
              plot sin(x*a)
              pause -1
              if(a<5) reread
        and from within [1mgnuplot [22myou submit the commands
              a=0
              load 'looper'
        The result will be five plots (separated by the [1mpause [22mmessage).

        Suppose the file "data" contains six columns of numbers with a
        total yrange from 0 to 10; the first is x and the next are five
        different functions of x.  Suppose also that the file "plotter"
        contains the commands
              c_p = c_p+1
              plot "$0" using 1:c_p with lines linetype c_p
              if(c_p <  n_p) reread
        and from within [1mgnuplot [22myou submit the commands
              n_p=6
              c_p=1
              unset key
              set yrange [0:10]
              set multiplot
              call 'plotter' 'data'
              unset multiplot
        The result is a single graph consisting of five plots.  The
        yrange must be set explicitly to guarantee that the five sepa-
        rate graphs (drawn on top of each other in multiplot mode) will
        have exactly the same axes.  The linetype must be specified;
        otherwise all the plots would be drawn with the same type.  See
        animate.dem in demo directory for an animated example.













   GNUPLOT 4.1                                                      129


        [1m82.  Reset[0m


        The [1mreset [22mcommand causes all graph-related options that can be
        set with the [1mset [22mcommand to take on their default values.  This
        command is useful, e.g., to restore the default graph settings
        at the end of a command file, or to return to a defined state
        after lots of settings have been changed within a command file.
        Please refer to the [1mset [22mcommand to see the default values that
        the various options take.

        The following are _not_ affected by [1mreset[22m.
             `set term` `set output` `set loadpath` `set fontpath` `set
        linetype`
             `set encoding` `set decimalsign` `set locale` `set psdir`

        [1mreset errors [22mclears only the error state variables GPVAL_ERRNO
        and GPVAL_ERRMSG.

        [1mreset bind [22mrestores all hotkey bindings to their default state.



        [1m83.  Save[0m


        The [1msave [22mcommand saves user-defined functions, variables, the
        [1mset term [22mstatus, all [1mset [22moptions, or all of these, plus the
        last [1mplot [22m([1msplot[22m) command to the specified file.

        Syntax:
              save  {<option>} '<filename>'

        where <option> is [1mfunctions[22m, [1mvariables[22m, [1mterminal [22mor [1mset[22m. If no
        option is used, [1mgnuplot [22msaves functions, variables, [1mset [22moptions
        and the last [1mplot [22m([1msplot[22m) command.

        [1msave[22md files are written in text format and may be read by the
        [1mload [22mcommand. For [1msave [22mwith the [1mset [22moption or without any
        option, the [1mterminal [22mchoice and the [1moutput [22mfilename are written
        out as a comment, to get an output file that works in other
        installations of gnuplot, without changes and without risk of
        unwillingly overwriting files.

        [1msave terminal [22mwill write out just the [1mterminal [22mstatus, without
        the comment marker in front of it. This is mainly useful for
        switching the [1mterminal [22msetting for a short while, and getting
        back to the previously set terminal, afterwards, by loading the
        saved [1mterminal [22mstatus. Note that for a single gnuplot session
        you may rather use the other method of saving and restoring
        current terminal by the commands [1mset term push [22mand [1mset term[0m
        [1mpop[22m, see [1mset term[22m.











   GNUPLOT 4.1                                                      130


        The filename must be enclosed in quotes.

        The special filename "-" may be used to [1msave [22mcommands to stan-
        dard output.  On systems which support a popen function (Unix),
        the output of save can be piped through an external program by
        starting the file name with a '|'.  This provides a consistent
        interface to [1mgnuplot[22m's internal settings to programs which com-
        municate with [1mgnuplot [22mthrough a pipe.  Please see help for
        [1mbatch/interactive [22mfor more details.

        Examples:
              save 'work.gnu'
              save functions 'func.dat'
              save var 'var.dat'
              save set 'options.dat'
              save term 'myterm.gnu'
              save '-'
              save '|grep title >t.gp'



        [1m84.  Set-show[0m


        The [1mset [22mcommand can be used to set _lots_ of options.  No
        screen is drawn, however, until a [1mplot[22m, [1msplot[22m, or [1mreplot [22mcom-
        mand is given.

        The [1mshow [22mcommand shows their settings;  [1mshow all [22mshows all the
        settings.

        Options changed using [1mset [22mcan be returned to the default state
        by giving the corresponding [1munset [22mcommand.  See also the [1mreset[0m
        command, which returns all settable parameters to default val-
        ues.

        If a variable contains time/date data, [1mshow [22mwill display it
        according to the format currently defined by [1mset timefmt[22m, even
        if that was not in effect when the variable was initially
        defined.  The [1mset [22mand [1munset [22mcommands may optionally contain an
        iteration clause.  See [1miteration[22m.





             [1m84.1.  Angles[0m


             By default, [1mgnuplot [22massumes the independent variable in
             polar graphs is in units of radians.  If [1mset angles[0m
             [1mdegrees [22mis specified before [1mset polar[22m, then the default
             range is [0:360] and the independent variable has units of










   GNUPLOT 4.1                                                      131


             degrees.  This is particularly useful for plots of data
             files.  The angle setting also applies to 3D mapping as
             set via the [1mset mapping [22mcommand.

             Syntax:
                   set angles {degrees | radians}
                   show angles

             The angle specified in [1mset grid polar [22mis also read and
             displayed in the units specified by [1mset angles[22m.

             [1mset angles [22malso affects the arguments of the machine-
             defined functions sin(x), cos(x) and tan(x), and the out-
             puts of asin(x), acos(x), atan(x), atan2(x), and arg(x).
             It has no effect on the arguments of hyperbolic functions
             or Bessel functions.  However, the output arguments of
             inverse hyperbolic functions of complex arguments are
             affected; if these functions are used, [1mset angles radians[0m
             must be in effect to maintain consistency between input
             and output arguments.

                   x={1.0,0.1}
                   set angles radians
                   y=sinh(x)
                   print y         #prints {1.16933, 0.154051}
                   print asinh(y)  #prints {1.0, 0.1}
             but
                   set angles degrees
                   y=sinh(x)
                   print y         #prints {1.16933, 0.154051}
                   print asinh(y)  #prints {57.29578, 5.729578}
             See also poldat.dem: polar plot using [1mset angles [22mdemo.



             [1m84.2.  Arrow[0m


             Arbitrary arrows can be placed on a plot using the [1mset[0m
             [1marrow [22mcommand.

             Syntax:
                   set arrow {<tag>} {from <position>} {to|rto <posi-
             tion>}
                             { {arrowstyle | as <arrow_style>}
                               | { {nohead | head | backhead | heads}
                                   {size <length>,<angle>{,<backan-
             gle>}}
                                   {filled | empty | nofilled}
                                   {front | back}
                                   { {linestyle | ls <line_style>}
                                     | {linetype | lt <line_type>}
                                       {linewidth | lw <line_width} } }










   GNUPLOT 4.1                                                      132


             }

                   unset arrow {<tag>}
                   show arrow {<tag>}

             <tag> is an integer that identifies the arrow.  If no tag
             is given, the lowest unused tag value is assigned automat-
             ically.  The tag can be used to delete or change a spe-
             cific arrow.  To change any attribute of an existing
             arrow, use the [1mset arrow [22mcommand with the appropriate tag
             and specify the parts of the arrow to be changed.

             The <position>s are specified by either x,y or x,y,z, and
             may be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mchar-[0m
             [1macter [22mto select the coordinate system.  Unspecified coor-
             dinates default to 0.  The end points can be specified in
             one of five coordinate systems---[1mfirst [22mor [1msecond [22maxes,
             [1mgraph[22m, [1mscreen[22m, or [1mcharacter[22m.  See [1mcoordinates [22mfor details.
             A coordinate system specifier does not carry over from the
             "from" position to the "to" position.  Arrows outside the
             screen boundaries are permitted but may cause device
             errors.  If the end point is specified by "rto" instead of
             "to" it is drawn relatively to the start point.  For lin-
             ear axes, [1mgraph [22mand [1mscreen [22mcoordinates, the distance
             between the start and the end point corresponds to the
             given relative coordinate.  For logarithmic axes, the rel-
             ative given coordinate corresponds to the factor of the
             coordinate between start and end point.  Thus, a negative
             relative value or zero are not allowed for logarithmic
             axes.

             Specifying [1mnohead [22mproduces an arrow drawn without a
             head---a line segment.  This gives you yet another way to
             draw a line segment on the plot.  By default, an arrow has
             a head at its end. Specifying [1mbackhead [22mdraws an arrow head
             at the start point of the arrow while [1mheads [22mdraws arrow
             heads on both ends of the line.  Not all terminal types
             support double-ended arrows.

             Head size can be controlled by [1msize <length>,<angle> [22mor
             [1msize <length>,<angle>,<backangle>[22m, where [1m<length> [22mdefines
             length of each branch of the arrow head and [1m<angle> [22mthe
             angle (in degrees) they make with the arrow.  [1m<Length> [22mis
             in x-axis units; this can be changed by [1mfirst[22m, [1msecond[22m,
             [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mbefore the <length>;  see
             [1mcoordinates [22mfor details.  [1m<Backangle> [22monly takes effect
             when [1mfilled [22mor [1mempty [22mis also used.  Then, [1m<backangle> [22mis
             the angle (in degrees) the back branches make with the
             arrow (in the same direction as [1m<angle>[22m).  The [1mfig [22mtermi-
             nal has a restricted backangle function. It supports three
             different angles. There are two thresholds: Below 70
             degrees, the arrow head gets an indented back angle. Above
             110 degrees, the arrow head has an acute back angle.










   GNUPLOT 4.1                                                      133


             Between these thresholds, the back line is straight.

             Specifying [1mfilled [22mproduces filled arrow heads (if heads
             are used).  Filling is supported on filled-polygon capable
             terminals, see help of [1mpm3d [22mfor their list, otherwise the
             arrow heads are closed but not filled.  The same result
             (closed but not filled arrow head) is reached by specify-
             ing [1mempty[22m.  Further, filling and outline is obviously not
             supported on terminals drawing arrows by their own spe-
             cific routines, like [1mmetafont[22m, [1mmetapost[22m, [1mlatex [22mor [1mtgif[22m.

             The line style may be selected from a user-defined list of
             line styles (see [1mset style line[22m) or may be defined here by
             providing values for <line_type> (an index from the
             default list of styles) and/or <line_width> (which is a
             multiplier for the default width).

             Note, however, that if a user-defined line style has been
             selected, its properties (type and width) cannot be
             altered merely by issuing another [1mset arrow [22mcommand with
             the appropriate index and [1mlt [22mor [1mlw[22m.

             If [1mfront [22mis given, the arrow is written on top of the
             graphed data. If [1mback [22mis given (the default), the arrow is
             written underneath the graphed data.  Using [1mfront [22mwill
             prevent an arrow from being obscured by dense data.

             Examples:

             To set an arrow pointing from the origin to (1,2) with
             user-defined style 5, use:
                   set arrow to 1,2 ls 5

             To set an arrow from bottom left of plotting area to
             (-5,5,3), and tag the arrow number 3, use:
                   set arrow 3 from graph 0,0 to -5,5,3

             To change the preceding arrow to end at 1,1,1, without an
             arrow head and double its width, use:
                   set arrow 3 to 1,1,1 nohead lw 2

             To draw a vertical line from the bottom to the top of the
             graph at x=3, use:
                   set arrow from 3, graph 0 to 3, graph 1 nohead

             To draw a vertical arrow with T-shape ends, use:
                   set arrow 3 from 0,-5 to 0,5 heads size screen
             0.1,90

             To draw an arrow relatively to the start point, where the
             relative distances are given in graph coordinates, use:
                   set arrow from 0,-5 rto graph 0.1,0.1











   GNUPLOT 4.1                                                      134


             To draw an arrow with relative end point in logarithmic x
             axis, use:
                   set logscale x
                   set arrow from 100,-5 rto 10,10
             This draws an arrow from 100,-5 to 1000,5. For the loga-
             rithmic x axis, the relative coordinate 10 means "factor
             10" while for the linear y axis, the relative coordinate
             10 means "difference 10".

             To delete arrow number 2, use:
                   unset arrow 2

             To delete all arrows, use:
                   unset arrow

             To show all arrows (in tag order), use:
                   show arrow

             arrows demos.




             [1m84.3.  Autoscale[0m


             Autoscaling may be set individually on the x, y or z axis
             or globally on all axes. The default is to autoscale all
             axes.  If you want to autoscale based on a subset of the
             plots in the figure, you can mark the other ones with the
             flag [1mnoautoscale[22m.  See [1mdatafile[22m.

             Syntax:
                   set autoscale {<axes>{|min|max|fixmin|fixmax|fix} |
             fix | keepfix}
                   unset autoscale {<axes>}
                   show autoscale

             where <axes> is either [1mx[22m, [1my[22m, [1mz[22m, [1mcb[22m, [1mx2[22m, [1my2 [22mor [1mxy[22m.  A key-
             word with [1mmin [22mor [1mmax [22mappended (this cannot be done with
             [1mxy[22m) tells [1mgnuplot [22mto autoscale just the minimum or maximum
             of that axis.  If no keyword is given, all axes are
             autoscaled.

             A keyword with [1mfixmin[22m, [1mfixmax [22mor [1mfix [22mappended tells gnu-
             plot to disable extension of the axis range to the next
             tic mark position, for autoscaled axes using equidistant
             tics; [1mset autoscale fix [22msets this for all axes.  Command
             [1mset autoscale keepfix [22mautoscales all axes while keeping
             the fix settings.

             When autoscaling, the axis range is automatically computed
             and the dependent axis (y for a [1mplot [22mand z for [1msplot[22m) is










   GNUPLOT 4.1                                                      135


             scaled to include the range of the function or data being
             plotted.

             If autoscaling of the dependent axis (y or z) is not set,
             the current y or z range is used.

             Autoscaling the independent variables (x for [1mplot [22mand x,y
             for [1msplot[22m) is a request to set the domain to match any
             data file being plotted.  If there are no data files,
             autoscaling an independent variable has no effect.  In
             other words, in the absence of a data file, functions
             alone do not affect the x range (or the y range if plot-
             ting z = f(x,y)).

             Please see [1mset xrange [22mfor additional information about
             ranges.

             The behavior of autoscaling remains consistent in paramet-
             ric mode, (see [1mset parametric[22m).  However, there are more
             dependent variables and hence more control over x, y, and
             z axis scales.  In parametric mode, the independent or
             dummy variable is t for [1mplot[22ms and u,v for [1msplot[22ms.
             [1mautoscale [22min parametric mode, then, controls all ranges
             (t, u, v, x, y, and z) and allows x, y, and z to be fully
             autoscaled.

             Autoscaling works the same way for polar mode as it does
             for parametric mode for [1mplot[22m, with the extension that in
             polar mode [1mset dummy [22mcan be used to change the independent
             variable from t (see [1mset dummy[22m).

             When tics are displayed on second axes but no plot has
             been specified for those axes, x2range and y2range are
             inherited from xrange and yrange.  This is done _before_
             xrange and yrange are autoextended to a whole number of
             tics, which can cause unexpected results.  You can use the
             [1mfixmin [22mor [1mfixmax [22moptions to avoid this.

             Examples:

             This sets autoscaling of the y axis (other axes are not
             affected):
                   set autoscale y

             This sets autoscaling only for the minimum of the y axis
             (the maximum of the y axis and the other axes are not
             affected):
                   set autoscale ymin

             This disables extension of the x2 axis tics to the next
             tic mark, thus keeping the exact range as found in the
             plotted data and functions:
                   set autoscale x2fixmin










   GNUPLOT 4.1                                                      136


                   set autoscale x2fixmax

             This sets autoscaling of the x and y axes:
                   set autoscale xy

             This sets autoscaling of the x, y, z, x2 and y2 axes:
                   set autoscale

             This disables autoscaling of the x, y, z, x2 and y2 axes:
                   unset autoscale

             This disables autoscaling of the z axis only:
                   unset autoscale z




                  [1m84.3.1.  Parametric mode[0m


                  When in parametric mode ([1mset parametric[22m), the xrange
                  is as fully scalable as the y range.  In other words,
                  in parametric mode the x axis can be automatically
                  scaled to fit the range of the parametric function
                  that is being plotted.  Of course, the y axis can
                  also be automatically scaled just as in the non-para-
                  metric case.  If autoscaling on the x axis is not
                  set, the current x range is used.

                  Data files are plotted the same in parametric and
                  non-parametric mode.  However, there is a difference
                  in mixed function and data plots: in non-parametric
                  mode with autoscaled x, the x range of the datafile
                  controls the x range of the functions; in parametric
                  mode it has no influence.

                  For completeness a last command [1mset autoscale t [22mis
                  accepted.  However, the effect of this "scaling" is
                  very minor.  When [1mgnuplot [22mdetermines that the t range
                  would be empty, it makes a small adjustment if
                  autoscaling is true.  Otherwise, [1mgnuplot [22mgives an
                  error.  Such behavior may, in fact, not be very use-
                  ful and the command [1mset autoscale t [22mis certainly
                  questionable.

                  [1msplot [22mextends the above ideas as you would expect.
                  If autoscaling is set, then x, y, and z ranges are
                  computed and each axis scaled to fit the resulting
                  data.














   GNUPLOT 4.1                                                      137


                  [1m84.3.2.  Polar mode[0m


                  When in polar mode ([1mset polar[22m), the xrange and the
                  yrange may be left in autoscale mode.  If [1mset rrange[0m
                  is used to limit the extent of the polar axis, then
                  xrange and yrange will adjust to match this automati-
                  cally.  However, explicit xrange and yrange commands
                  can later be used to make further adjustments.  See
                  [1mset rrange[22m.  The trange may also be autoscaled.  Note
                  that if the trange is contained within one quadrant,
                  autoscaling will produce a polar plot of only that
                  single quadrant.

                  Explicitly setting one or two ranges but not others
                  may lead to unexpected results.  See also polar
                  demos.



             [1m84.4.  Bars[0m


             The [1mset bars [22mcommand controls the tics at the ends of
             error bars, and also at the end of the whiskers belonging
             to a boxplot.

             Syntax:
                   set bars {small | large | fullwidth | <size>} {front
             | back}
                   unset bars
                   show bars

             [1msmall [22mis a synonym for 0.0, and [1mlarge [22mfor 1.0.  The
             default is 1.0 if no size is given.

             The keyword [1mfullwidth [22mis relevant only to boxplots and to
             histograms with errorbars.  It sets the width of the
             errorbar ends to be the same as the width of the associ-
             ated box.  It does not change the width of the box itself.

             The [1mfront [22mand [1mback [22mkeywords are relevant only to errorbars
             attached to filled rectangles (boxes, candlesticks, his-
             tograms).



             [1m84.5.  Bind[0m


             Show the current state of all hotkey bindings. See [1mbind[22m.












   GNUPLOT 4.1                                                      138


             [1m84.6.  Bmargin[0m


             The command [1mset bmargin [22msets the size of the bottom mar-
             gin.  Please see [1mset margin [22mfor details.



             [1m84.7.  Border[0m


             The [1mset border [22mand [1munset border [22mcommands control the dis-
             play of the graph borders for the [1mplot [22mand [1msplot [22mcommands.
             Note that the borders do not necessarily coincide with the
             axes; with [1mplot [22mthey often do, but with [1msplot [22mthey usually
             do not.

             Syntax:
                   set border {<integer>} {front | back} {linewidth |
             lw <line_width>}
                              {{linestyle | ls <line_style>} | {line-
             type | lt <line_type>}}
                   unset border
                   show border

             With a [1msplot [22mdisplayed in an arbitrary orientation, like
             [1mset view 56,103[22m, the four corners of the x-y plane can be
             referred to as "front", "back", "left" and "right".  A
             similar set of four corners exist for the top surface, of
             course.  Thus the border connecting, say, the back and
             right corners of the x-y plane is the "bottom right back"
             border, and the border connecting the top and bottom front
             corners is the "front vertical".  (This nomenclature is
             defined solely to allow the reader to figure out the table
             that follows.)

             The borders are encoded in a 12-bit integer: the bottom
             four bits control the border for [1mplot [22mand the sides of the
             base for [1msplot[22m; the next four bits control the verticals
             in [1msplot[22m; the top four bits control the edges on top of
             the [1msplot[22m.  In detail, [1m<integer> [22mshould be the sum of the
             appropriate entries from the following table:





















   GNUPLOT 4.1                                                      139


                 +--------------------------------------+
                 |Bit      plot            splot        |
                 +--------------------------------------+
                 | 1      bottom     bottom left front  |
                 | 2       left       bottom left back  |
                 | 4        top      bottom right front |
                 | 8       right     bottom right back  |
                 | 16    no effect     left vertical    |
                 | 32    no effect     back vertical    |
                 | 64    no effect     right vertical   |
                 |128    no effect     front vertical   |
                 |256    no effect     top left back    |
                 |512    no effect     top right back   |
                 |1024   no effect     top left front   |
                 |2048   no effect    top right front   |
                 +--------------------------------------+




   Various bits or combinations of bits may be added together in the
   command.

   The default is 31, which is all four sides for [1mplot[22m, and base and z
   axis for [1msplot[22m.

   In 2D plots the border is normally drawn on top of all plots ele-
   ments ([1mfront[22m). If you want the border to be drawn behind the plot
   elements, use [1mset border back[22m.

   Using the optional <line_style>, <line_type> and <line_width> speci-
   fiers, the way the border lines are drawn can be influenced (limited
   by what the current terminal driver supports).

   For [1mplot[22m, tics may be drawn on edges other than bottom and left by
   enabling the second axes -- see [1mset xtics [22mfor details.

   If a [1msplot [22mdraws only on the base, as is the case with "[1munset sur-[0m
   [1mface; set contour base[22m", then the verticals and the top are not
   drawn even if they are specified.

   The [1mset grid [22moptions 'back', 'front' and 'layerdefault' also control
   the order in which the border lines are drawn with respect to the
   output of the plotted data.

   Examples:

   Draw default borders:
         set border

   Draw only the left and bottom ([1mplot[22m) or both front and back bottom
   left ([1msplot[22m) borders:
         set border 3










   GNUPLOT 4.1                                                      140


   Draw a complete box around a [1msplot[22m:
         set border 4095

   Draw a topless box around a [1msplot[22m, omitting the front vertical:
         set border 127+256+512 # or set border 1023-128

   Draw only the top and right borders for a [1mplot [22mand label them as
   axes:
         unset xtics; unset ytics; set x2tics; set y2tics; set border
   12




             [1m84.8.  Boxwidth[0m


             The [1mset boxwidth [22mcommand is used to set the default width
             of boxes in the [1mboxes[22m, [1mboxerrorbars[22m, [1mboxplot[22m, [1mcandlesticks[0m
             and [1mhistograms [22mstyles.

             Syntax:
                   set boxwidth {<width>} {absolute|relative}
                   show boxwidth

             By default, adjacent boxes are extended in width until
             they touch each other.  A different default width may be
             specified using the [1mset boxwidth [22mcommand.  [1mRelative [22mwidths
             are interpreted as being a fraction of this default width.

             An explicit value for the boxwidth is interpreted as being
             a number of units along the current x axis ([1mabsolute[22m)
             unless the modifier [1mrelative [22mis given.  If the x axis is a
             log-scale (see [1mset log[22m) then the value of boxwidth is
             truly "absolute" only at x=1; this physical width is main-
             tained everywhere along the axis (i.e. the boxes do not
             become narrower the value of x increases). If the range
             spanned by a log scale x axis is far from x=1, some exper-
             imentation may be required to find a useful value of
             boxwidth.

             The default is superseded by explicit width information
             taken from an extra data column in styles [1mboxes [22mor [1mboxer-[0m
             [1mrorbars[22m.  In a four-column data set, the fourth column
             will be interpreted as the box width unless the width is
             set to -2.0, in which case the width will be calculated
             automatically.  See [1mstyle boxes [22mand [1mstyle boxerrorbars [22mfor
             more details.

             To set the box width to automatic use the command
                   set boxwidth

             or, for four-column data,










   GNUPLOT 4.1                                                      141


                   set boxwidth -2

             The same effect can be achieved with the [1musing [22mkeyword in
             [1mplot[22m:
                   plot 'file' using 1:2:3:4:(-2)

             To set the box width to half of the automatic size use
                   set boxwidth 0.5 relative

             To set the box width to an absolute value of 2 use
                   set boxwidth 2 absolute



             [1m84.9.  Clabel[0m


             [1mgnuplot [22mwill vary the linetype used for each contour level
             when clabel is set.  When this option on (the default), a
             legend labels each linestyle with the z level it repre-
             sents.  It is not possible at present to separate the con-
             tour labels from the surface key.

             Syntax:
                   set clabel {'<format>'}
                   unset clabel
                   show clabel

             The default for the format string is %8.3g, which gives
             three decimal places.  This may produce poor label align-
             ment if the key is altered from its default configuration.

             The first contour linetype, or only contour linetype when
             clabel is off, is the surface linetype +1; contour points
             are the same style as surface points.

             See also [1mset contour[22m.



             [1m84.10.  Clip[0m


             [1mgnuplot [22mcan clip data points and lines that are near the
             boundaries of a graph.

             Syntax:
                   set clip <clip-type>
                   unset clip <clip-type>
                   show clip

             Three clip types for points and lines are supported by
             [1mgnuplot[22m: [1mpoints[22m, [1mone[22m, and [1mtwo[22m. One, two, or all three clip










   GNUPLOT 4.1                                                      142


             types may be active for a single graph.  Note that clip-
             ping of color filled quadrangles drawn by [1mpm3d [22mmaps and
             surfaces is not controlled by this command, but by [1mset[0m
             [1mpm3d clip1in [22mand [1mset pm3d clip4in[22m.

             The [1mpoints [22mclip type forces [1mgnuplot [22mto clip (actually, not
             plot at all) data points that fall within but too close to
             the boundaries.  This is done so that large symbols used
             for points will not extend outside the boundary lines.
             Without clipping points near the boundaries, the plot may
             look bad.  Adjusting the x and y ranges may give similar
             results.

             Setting the [1mone [22mclip type causes [1mgnuplot [22mto draw a line
             segment which has only one of its two endpoints within the
             graph.  Only the in-range portion of the line is drawn.
             The alternative is to not draw any portion of the line
             segment.

             Some lines may have both endpoints out of range, but pass
             through the graph.  Setting the [1mtwo [22mclip-type allows the
             visible portion of these lines to be drawn.

             In no case is a line drawn outside the graph.

             The defaults are [1mnoclip points[22m, [1mclip one[22m, and [1mnoclip two[22m.

             To check the state of all forms of clipping, use
                   show clip

             For backward compatibility with older versions, the fol-
             lowing forms are also permitted:
                   set clip
                   unset clip

             [1mset clip [22mis synonymous with [1mset clip points[22m; [1munset clip[0m
             turns off all three types of clipping.



             [1m84.11.  Cntrparam[0m


             [1mset cntrparam [22mcontrols the generation of contours and
             their smoothness for a contour plot. [1mshow contour [22mdisplays
             current settings of [1mcntrparam [22mas well as [1mcontour[22m.

             Syntax:
                   set cntrparam { { linear
                                   | cubicspline
                                   | bspline
                                   | points <n>
                                   | order <n>










   GNUPLOT 4.1                                                      143


                                   | levels { auto {<n>} | <n>
                                              | discrete <z1>
             {,<z2>{,<z3>...}}
                                              | incremental <start>,
             <incr> {,<end>}
                                            }
                                   }
                                 }
                   show contour

             This command has two functions.  First, it sets the values
             of z for which contour points are to be determined (by
             linear interpolation between data points or function
             isosamples.)  Second, it controls the way contours are
             drawn between the points determined to be of equal z.  <n>
             should be an integral constant expression and <z1>, <z2>
             ... any constant expressions.  The parameters are:

             [1mlinear[22m, [1mcubicspline[22m, [1mbspline[22m---Controls type of approxima-
             tion or interpolation.  If [1mlinear[22m, then straight line seg-
             ments connect points of equal z magnitude.  If [1mcubic-[0m
             [1mspline[22m, then piecewise-linear contours are interpolated
             between the same equal z points to form somewhat smoother
             contours, but which may undulate.  If [1mbspline[22m, a guaran-
             teed-smoother curve is drawn, which only approximates the
             position of the points of equal-z.

             [1mpoints[22m---Eventually all drawings are done with piecewise-
             linear strokes.  This number controls the number of line
             segments used to approximate the [1mbspline [22mor [1mcubicspline[0m
             curve.  Number of cubicspline or bspline segments
             (strokes) = [1mpoints [22m* number of linear segments.

             [1morder[22m---Order of the bspline approximation to be used.
             The bigger this order is, the smoother the resulting con-
             tour.  (Of course, higher order bspline curves will move
             further away from the original piecewise linear data.)
             This option is relevant for [1mbspline [22mmode only.  Allowed
             values are integers in the range from 2 (linear) to 10.

             [1mlevels[22m--- Selection of contour levels,  controlled by [1mauto[0m
             (default), [1mdiscrete[22m, [1mincremental[22m, and <n>, number of con-
             tour levels.

             For [1mauto[22m, <n> specifies a nominal number of levels; the
             actual number will be adjusted to give simple labels. If
             the surface is bounded by zmin and zmax, contours will be
             generated at integer multiples of dz between zmin and
             zmax, where dz is 1, 2, or 5 times some power of ten (like
             the step between two tic marks).

             For [1mlevels discrete[22m, contours will be generated at z =
             <z1>, <z2> ... as specified; the number of discrete levels










   GNUPLOT 4.1                                                      144


             sets the number of contour levels.  In [1mdiscrete [22mmode, any
             [1mset cntrparam levels <n> [22mare ignored.

             For [1mincremental[22m, contours are generated at values of z
             beginning at <start> and increasing by <increment>, until
             the number of contours is reached. <end> is used to deter-
             mine the number of contour levels, which will be changed
             by any subsequent [1mset cntrparam levels <n>[22m.  If the z axis
             is logarithmic, <increment> will be interpreted as a fac-
             tor, just like in [1mset ztics[22m.

             If the command [1mset cntrparam [22mis given without any argu-
             ments specified,  the defaults are used: linear, 5 points,
             order 4, 5 auto levels.

             Examples:
                   set cntrparam bspline
                   set cntrparam points 7
                   set cntrparam order 10

             To select levels automatically, 5 if the level increment
             criteria are met:
                   set cntrparam levels auto 5

             To specify discrete levels at .1, .37, and .9:
                   set cntrparam levels discrete .1,1/exp(1),.9

             To specify levels from 0 to 4 with increment 1:
                   set cntrparam levels incremental  0,1,4

             To set the number of levels to 10 (changing an incremental
             end or possibly the number of auto levels):
                   set cntrparam levels 10

             To set the start and increment while retaining the number
             of levels:
                   set cntrparam levels incremental 100,50

             See also [1mset contour [22mfor control of where the contours are
             drawn, and [1mset clabel [22mfor control of the format of the
             contour labels and linetypes.

             See also contours demo (contours.dem) and contours with
             user defined levels demo (discrete.dem).



             [1m84.12.  Color box[0m



             The color scheme, i.e. the gradient of the smooth color
             with min_z and max_z values of [1mpm3d[22m's [1mpalette[22m, is drawn in










   GNUPLOT 4.1                                                      145


             a color box unless [1munset colorbox[22m.

                   set colorbox
                   set colorbox {
                              { vertical | horizontal }
                              { default | user }
                              { origin x, y }
                              { size x, y }
                              { front | back }
                              { noborder | bdefault | border [line
             style] }
                            }
                   show colorbox
                   unset colorbox

             Color box position can be [1mdefault [22mor [1muser[22m.  If the latter
             is specified the values as given with the [1morigin [22mand [1msize[0m
             subcommands are used. The box can be drawn after ([1mfront[22m)
             or before ([1mback[22m) the graph or the surface.

             The orientation of the color gradient can be switched by
             options [1mvertical [22mand [1mhorizontal[22m.

             [1morigin x, y [22mand [1msize x, y [22mare used only in combination
             with the [1muser [22moption. The x and y values are interpreted
             as screen coordinates by default, and this is the only
             legal option for 3D plots. 2D plots, including splot with
             [1mset view map[22m, allow any coordinate system to be specified.
             Try for example:
                 set colorbox horiz user origin .1,.02 size .8,.04
             which will draw a horizontal gradient somewhere at the
             bottom of the graph.

             [1mborder [22mturns the border on (this is the default). [1mnoborder[0m
             turns the border off. If an positive integer argument is
             given after [1mborder[22m, it is used as a line style tag which
             is used for drawing the border, e.g.:
                 set style line 2604 linetype -1 linewidth .4
                 set colorbox border 2604
             will use line style [1m2604[22m, a thin line with the default
             border color (-1) for drawing the border. [1mbdefault [22m(which
             is the default) will use the default border line style for
             drawing the border of the color box.

             The axis of the color box is called [1mcb [22mand it is con-
             trolled by means of the usual axes commands, i.e.
             [1mset/unset/show [22mwith [1mcbrange[22m, [1m[m]cbtics[22m, [1mformat cb[22m, [1mgrid[0m
             [1m[m]cb[22m, [1mcblabel[22m, and perhaps even [1mcbdata[22m, [1m[no]cbdtics[22m,
             [1m[no]cbmtics[22m.

             [1mset colorbox [22mwithout any parameter switches the position
             to default.  [1munset colorbox [22mresets the default parameters
             for the colorbox and switches the colorbox off.










   GNUPLOT 4.1                                                      146


             See also help for [1mset pm3d[22m, [1mset palette[22m, [1mx11 pm3d[22m, and [1mset[0m
             [1mstyle line[22m.



             [1m84.13.  Colornames[0m


             Gnuplot knows a limited number of color names. You can use
             these to define the color range spanned by a pm3d palette,
             or to assign a terminal-independent color to a particular
             linetype or linestyle. To see the list of known color
             names, use the command [1mshow colornames[22m.   Example:

                   set style line 1 linecolor rgb "sea-green"



             [1m84.14.  Contour[0m


             [1mset contour [22menables contour drawing for surfaces.  This
             option is available for [1msplot [22monly.  It requires grid
             data, see [1mgrid_data [22mfor more details.  If contours are
             desired from non-grid data, [1mset dgrid3d [22mcan be used to
             create an appropriate grid.

             Syntax:
                   set contour {base | surface | both}
                   unset contour
                   show contour

             The three options specify where to draw the contours: [1mbase[0m
             draws the contours on the grid base where the x/ytics are
             placed, [1msurface [22mdraws the contours on the surfaces them-
             selves, and [1mboth [22mdraws the contours on both the base and
             the surface.  If no option is provided, the default is
             [1mbase[22m.

             See also [1mset cntrparam [22mfor the parameters that affect the
             drawing of contours, and [1mset clabel [22mfor control of
             labelling of the contours.

             The surface can be switched off (see [1mset surface[22m), giving
             a contour-only graph.  Though it is possible to use [1mset[0m
             [1msize [22mto enlarge the plot to fill the screen, more control
             over the output format can be obtained by writing the con-
             tour information to a file, and rereading it as a 2D
             datafile plot:

                   unset surface
                   set contour
                   set cntrparam ...










   GNUPLOT 4.1                                                      147


                   set table 'filename'
                   splot ...
                   unset table
                   # contour info now in filename
                   set term <whatever>
                   plot 'filename'

             In order to draw contours, the data should be organized as
             "grid data".  In such a file all the points for a single
             y-isoline are listed, then all the points for the next y-
             isoline, and so on.  A single blank line (a line contain-
             ing no characters other than blank spaces and a carriage
             return and/or a line feed) separates one y-isoline from
             the next.  See also [1msplot datafile[22m.

             See also contours demo (contours.dem) and contours with
             user defined levels demo (discrete.dem).



             [1m84.15.  Data style[0m


             This form of the command is deprecated. Please see [1mset[0m
             [1mstyle data[22m.



             [1m84.16.  Datafile[0m


             The [1mset datafile [22mcommand options control interpretation of
             fields read from input data files by the [1mplot[22m, [1msplot[22m, and
             [1mfit [22mcommands.  Six such options are currently implemented.




                  [1m84.16.1.  Set datafile fortran[0m


                  The [1mset datafile fortran [22mcommand enables a special
                  check for values in the input file expressed as For-
                  tran D or Q constants. This extra check slows down
                  the input process, and should only be selected if you
                  do in fact have datafiles containing Fortran D or Q
                  constants. The option can be disabled again using
                  [1munset datafile fortran[22m.















   GNUPLOT 4.1                                                      148


                  [1m84.16.2.  Set datafile nofpe_trap[0m


                  The [1mset datafile nofpe_trap [22mcommand tells gnuplot not
                  to re-initialize a floating point exception handler
                  before every expression evaluation used while reading
                  data from an input file.  This can significantly
                  speed data input from very large files at the risk of
                  program termination if a floating-point exception is
                  generated.



                  [1m84.16.3.  Set datafile missing[0m


                  The [1mset datafile missing [22mcommand allows you to tell
                  [1mgnuplot [22mwhat character string is used in a data file
                  to denote missing data.  Exactly how this missing
                  value will be treated depends on the [1musing [22mspecifier
                  of the [1mplot [22mor [1msplot [22mcommand.

                  Syntax:
                        set datafile missing {"<string>"}
                        show datafile missing
                        unset datafile

                  Example:
                        # Ignore entries containing IEEE NaN ("Not a
                  Number") code
                        set datafile missing "NaN"

                  Example:
                        set style data linespoints
                        plot '-'
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e
                        set datafile missing "?"
                        plot '-'
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e
                        plot '-' using 1:2
                           1 10
                           2 20
                           3 ?










   GNUPLOT 4.1                                                      149


                           4 40
                           5 50
                           e
                        plot '-' using 1:($2)
                           1 10
                           2 20
                           3 ?
                           4 40
                           5 50
                           e

                  The first [1mplot [22mwill recognize only the first datum in
                  the "3 ?" line.  It will use the single-datum-on-a-
                  line convention that the line number is "x" and the
                  datum is "y", so the point will be plotted (in this
                  case erroneously) at (2,3).

                  The second and third [1mplot [22mcommands will correctly
                  ignore the middle line.  The plotted line will con-
                  nect the points at (2,20) and (4,40).

                  The fourth [1mplot [22mwill also correctly ignore the middle
                  line, but the plotted line will not connect the
                  points at (2,20) and (4,40).

                  There is no default character for [1mmissing[22m, but in
                  many cases any non-parsible string of characters
                  found where a numerical value is expected will be
                  treated as missing data.




                  [1m84.16.4.  Set datafile separator[0m


                  The command [1mset datafile separator "<char>" [22mtells
                  [1mgnuplot [22mthat data fields in subsequent input files
                  are separated by <char> rather than by whitespace.
                  The most common use is to read in csv (comma-sepa-
                  rated value) files written by spreadsheet or database
                  programs. By default data fields are separated by
                  whitespace.

                  Syntax:
                        set datafile separator {"<char>" | whitespace}

                  Examples:
                        # Input file contains tab-separated fields
                        set datafile separator "\t"

                        # Input file contains comma-separated values
                  fields










   GNUPLOT 4.1                                                      150


                        set datafile separator ","



                  [1m84.16.5.  Set datafile commentschars[0m


                  The [1mset datafile commentschars [22mcommand allows you to
                  tell [1mgnuplot [22mwhat characters are used in a data file
                  to denote comments.  Gnuplot will ignore rest of the
                  line behind the specified characters if either of
                  them is the first non-blank character on the line.

                  Syntax:
                        set datafile commentschars {"<string>"}
                        show datafile commentschars
                        unset commentschars

                  Default value of the string is "#!" on VMS and "#"
                  otherwise.

                  Then, the following line in a data file is completely
                  ignored
                      # 1 2 3 4
                  but the following
                      1 # 3 4
                  produces rather unexpected plot unless
                      set datafile missing '#'
                  is specified as well.

                  Example:
                        set datafile commentschars "#!%"



                  [1m84.16.6.  Set datafile binary[0m


                  The [1mset datafile binary [22mcommand is used to set the
                  defaults when reading binary data files.  The syntax
                  matches precisely that used for commands [1mplot [22mand
                  [1msplot[22m.  See [1mbinary matrix [22mand [1mbinary general [22mfor
                  details about the keywords that can be present in
                  <binary list>.

                  Syntax:
                        set datafile binary <binary list>
                        show datafile binary
                        show datafile
                        unset datafile

                  Examples:
                        set datafile binary filetype=auto










   GNUPLOT 4.1                                                      151


                        set datafile binary array=(512,512) for-
                  mat="%uchar"

                        show datafile binary   # list current settings



             [1m84.17.  Decimalsign[0m


             The [1mset decimalsign [22mcommand selects a decimal sign for
             numbers printed into tic labels or [1mset label [22mstrings.

             Syntax:
                   set decimalsign {<value> | locale {"<locale>"}}
                   unset decimalsign
                   show decimalsign

             The argument <value> is a string to be used in place of
             the usual decimal point. Typical choices include the
             period, '.', and the comma, ',', but others may be useful,
             too.  If you omit the <value> argument, the decimal sepa-
             rator is not modified from the usual default, which is a
             period.  Unsetting decimalsign has the same effect as
             omitting <value>.

             Example:

             Correct typesetting in most European countries requires:
                   set decimalsign ','

             Please note: If you set an explicit string, this affects
             only numbers that are printed using gnuplot's gprintf()
             formatting routine, include axis tics.  It does not affect
             the format expected for input data, and it does not affect
             numbers printed with the sprintf() formatting routine. To
             change the behavior of both input and output formatting,
             instead use the form

                   set decimalsign locale

             This instructs the program to use both input and output
             formats in accordance with the current setting of the
             LC_ALL, LC_NUMERIC, or LANG environmental variables.

                   set decimalsign locale "foo"

             This instructs the program to format all input and output
             in accordance with locale "foo", which must be installed.
             If locale "foo" is not found then an error message is
             printed and the decimal sign setting is unchanged.  On
             linux systems you can get a list of the locales installed
             on your machine by typing "locale -a". A typical linux










   GNUPLOT 4.1                                                      152


             locale string is of the form "sl_SI.UTF-8".  A typical
             Windows locale string is of the form "Slovenian_Slove-
             nia.1250" or "slovenian". Please note that interpretation
             of the locale settings is done by the C library at run-
             time. Older C libraries may offer only partial support for
             locale settings such as the thousands grouping separator
             character.

                   set decimalsign locale; set decimalsign "."

             This sets all input and output to use whatever decimal
             sign is correct for the current locale, but over-rides
             this with an explicit '.' in numbers formatted using gnu-
             plot's internal gprintf() function.



             [1m84.18.  Dgrid3d[0m


             The [1mset dgrid3d [22mcommand enables, and can set parameters
             for, non-grid to grid data mapping.  See [1msplot grid_data[0m
             for more details about the grid data structure.

             Syntax:
                   set dgrid3d {<rows>} {,{<cols>}}
                               { splines |
                                 qnorm {<norm>} |
                                 (gauss | cauchy | exp | box | hann)
                                   {kdensity} {<dx>} {,<dy>} }
                   unset dgrid3d
                   show dgrid3d

             By default [1mdgrid3d [22mis disabled.  When enabled, 3D data
             read from a file are always treated as a scattered data
             set.  A grid with dimensions derived from a bounding box
             of the scattered data and size as specified by the
             row/col_size parameters is created for plotting and con-
             touring.  The grid is equally spaced in x (rows) and in y
             (columns); the z values are computed as weighted averages
             or spline interpolations of the scattered points' z val-
             ues. In other words, a regularly spaced grid is created
             and the a smooth approximation to the raw data is evalu-
             ated for all grid points. This approximation is plotted in
             place of the raw data.

             The number of columns defaults to the number of rows,
             which defaults to 10.

             Several algorithms are available to calculate the approxi-
             mation from the raw data. Some of these algorithms can
             take additional parameters.  These interpolations are such
             the closer the data point is to a grid point, the more










   GNUPLOT 4.1                                                      153


             effect it has on that grid point.

             The [1msplines [22malgorithm calculates an interpolation based on
             "thin plate splines". It does not take additional parame-
             ters.

             The [1mqnorm [22malgorithm calculates a weighted average of the
             input data at each grid point. Each data point is weighted
             inversely by its distance from the grid point raised to
             the norm power.  (Actually, the weights are given by the
             inverse of dx^norm + dy^norm, where dx and dy are the com-
             ponents of the separation of the grid point from each data
             point.  For some norms that are powers of two, specifi-
             cally 4, 8, and 16, the computation is optimized by using
             the Euclidean distance in the weight calculation,
             (dx^2+dy^2)^norm/2.  However, any non-negative integer can
             be used.)  The power of the norm can be specified as a
             single optional parameter.  This algorithm is the default.

             Finally, several smoothing kernels are available to calcu-
             late weighted averages: z = Sum_i w(d_i) * z_i / Sum_i
             w(d_i), where z_i is the value of the i-th data point and
             d_i is the distance between the current grid point and the
             location of the i-th data point. All kernels assign higher
             weights to data points that are close to the current grid
             point and lower weights to data points further away.

             The following kernels are available:
                   gauss :     w(d) = exp(-d*d)
                   cauchy :    w(d) = 1/(1 + d*d)
                   exp :       w(d) = exp(-d)
                   box :       w(d) = 1                     if d<1
                                    = 0                     otherwise
                   hann :      w(d) = 0.5*(1-cos(2*pi*d))   if d<1
                               w(d) = 0                     otherwise

             When using one of these five smoothing kernels, up to two
             additional numerical parameters can be specified: dx and
             dy. These are used to rescale the coordinate differences
             when calculating the distance: d_i = sqrt( ((x-x_i)/dx)**2
             + ((y-y_i)/dy)**2 ), where x,y are the coordinates of the
             current grid point and x_i,y_i are the coordinates of the
             i-th data point. The value of dy defaults to the value of
             dx, which defaults to 1. The parameters dx and dy make it
             possible to control the radius over which data points con-
             tribute to a grid point IN THE UNITS OF THE DATA ITSELF.

             The optional keyword [1mkdensity2d[22m, which must come after the
             name of the kernel, but before the (optional) scale param-
             eters, modifies the algorithm so that the values calcu-
             lated for the grid points are not divided by the sum of
             the weights ( z = Sum_i w(d_i) * z_i ). If all z_i are
             constant, this effectively plots a bivariate kernel










   GNUPLOT 4.1                                                      154


             density estimate: a kernel function (one of the five
             defined above) is placed at each data point, the sum of
             these kernels is evaluated at every grid point, and this
             smooth surface is plotted instead of the original data.
             This is similar in principle to + what the [1msmooth kdensity[0m
             option does to 1D datasets.  (See kdensity2d.dem for usage
             demo)

             A slightly different syntax is also supported for reasons
             of backwards compatibility. If no interpolation algorithm
             has been explicitly selected, the [1mqnorm [22malgorithm is
             assumed. Up to three comma-separated, optional parameters
             can be specified, which are interpreted as the the number
             of rows, the number of columns, and the norm value,
             respectively.

             The [1mdgrid3d [22moption is a simple scheme which replaces scat-
             tered data with weighted averages on a regular grid.  More
             sophisticated approaches to this problem exist and should
             be used to preprocess the data outside [1mgnuplot [22mif this
             simple solution is found inadequate.

             See also dgrid3d.dem: dgrid3d demo.  and scatter.dem:
             dgrid3d demo.




             [1m84.19.  Dummy[0m


             The [1mset dummy [22mcommand changes the default dummy variable
             names.

             Syntax:
                   set dummy {<dummy-var>} {,<dummy-var>}
                   show dummy

             By default, [1mgnuplot [22massumes that the independent, or
             "dummy", variable for the [1mplot [22mcommand is "t" if in para-
             metric or polar mode, or "x" otherwise.  Similarly the
             independent variables for the [1msplot [22mcommand are "u" and
             "v" in parametric mode ([1msplot [22mcannot be used in polar
             mode), or "x" and "y" otherwise.

             It may be more convenient to call a dummy variable by a
             more physically meaningful or conventional name.  For
             example, when plotting time functions:

                   set dummy t
                   plot sin(t), cos(t)

             At least one dummy variable must be set on the command;










   GNUPLOT 4.1                                                      155


             [1mset dummy [22mby itself will generate an error message.

             Examples:
                   set dummy u,v
                   set dummy ,s

             The second example sets the second variable to s.



             [1m84.20.  Encoding[0m


             The [1mset encoding [22mcommand selects a character encoding.
             Syntax:
                   set encoding {<value>}
                   set encoding locale
                   show encoding

             Valid values are
                default     - tells a terminal to use its default
             encoding
                iso_8859_1  - the most common Western European encoding
             used by many
                              Unix workstations and by MS-Windows. This
             encoding is
                              known in the PostScript world as 'ISO-
             Latin1'.
                iso_8859_15 - a variant of iso_8859_1 that includes the
             Euro symbol
                iso_8859_2  - used in Central and Eastern Europe
                iso_8859_9  - used in Turkey (also known as Latin5)
                koi8r       - popular Unix cyrillic encoding
                koi8u       - ukrainian Unix cyrillic encoding
                cp437       - codepage for MS-DOS
                cp850       - codepage for OS/2, Western Europe
                cp852       - codepage for OS/2, Central and Eastern
             Europe
                cp950       - MS version of Big5 (emf terminal only)
                cp1250      - codepage for MS Windows, Central and
             Eastern Europe
                cp1251      - codepage for 8-bit Russian, Serbian, Bul-
             garian, Macedonian
                cp1254      - codepage for MS Windows, Turkish (super-
             set of Latin5)
                sjis        - shift-JIS Japanese encoding
                utf8        - variable-length (multibyte) representa-
             tion of Unicode
                              entry point for each character

             The command [1mset encoding locale [22mis different from the
             other options.  It attempts to determine the current
             locale from the runtime environment.  On most systems this










   GNUPLOT 4.1                                                      156


             is controlled by the environmental variables LC_ALL,
             LC_CTYPE, or LANG.  This mechanism is necessary, for exam-
             ple, to pass multibyte character encodings such as UTF-8
             or EUC_JP to the wxt and cairopdf terminals.  This command
             does not affect the locale-specific representation of
             dates or numbers.  See also [1mset locale [22mand [1mset decimal-[0m
             [1msign[22m.

             Generally you must set the encoding before setting the
             terminal type.  Note that encoding is not supported by all
             terminal drivers and that the device must be able to pro-
             duce the desired non-standard characters.



             [1m84.21.  Fit[0m


             The [1mfit [22msetting defines where the [1mfit [22mcommand writes its
             output.

             Syntax:
                   set fit {logfile {"<filename>"}} {{no}errorvari-
             ables} {{no}quiet}
                   unset fit
                   show fit

             The <filename> argument must be enclosed in single or dou-
             ble quotes.

             If no filename is given or [1munset fit [22mis used the log file
             is reset to its default value "fit.log" or the value of
             the environmental variable [1mFIT_LOG[22m.

             If the given logfile name ends with a / or \, it is inter-
             preted to be a directory name, and the actual filename
             will be "fit.log" in that directory.

             If the [1merrorvariables [22moption is turned on, the error of
             each fitted parameter computed by [1mfit [22mwill be copied to a
             user-defined variable whose name is formed by appending
             "_err" to the name of the parameter itself.  This is use-
             ful mainly to put the parameter and its error onto a plot
             of the data and the fitted function, for reference, as in:

                    set fit errorvariables
                    fit f(x) 'datafile' using 1:2 via a, b
                    print "error of a is:", a_err
                    set label 'a=%6.2f', a, '+/- %6.2f', a_err
                    plot 'datafile' using 1:2, f(x)

             By default the information written to the log file is also
             echoed to the terminal session. [1mset fit quiet [22mturns off










   GNUPLOT 4.1                                                      157


             the echo.



             [1m84.22.  Fontpath[0m


             The [1mfontpath [22msetting defines additional locations for font
             files searched when including font files. Currently only
             the postscript terminal supports [1mfontpath[22m. If a file can-
             not be found in the current directory, the directories in
             [1mfontpath [22mare tried. Further documentation concerning the
             supported file formats is included in the [1mterminal post-[0m
             [1mscript [22msection of the documentation.

             Syntax:
                   set fontpath {"pathlist1" {"pathlist2"...}}
                   show fontpath

             Path names may be entered as single directory names, or as
             a list of path names separated by a platform-specific path
             separator, eg. colon (':') on Unix, semicolon (';') on
             DOS/Windows/OS/2 platforms.  The [1mshow fontpath[22m, [1msave [22mand
             [1msave set [22mcommands replace the platform-specific separator
             with a space character (' ') for maximum portability. If a
             directory name ends with an exclamation mark ('!') also
             the subdirectories of this directory are searched for font
             files.

             If the environmental variable GNUPLOT_FONTPATH is set, its
             contents are appended to [1mfontpath[22m.  If it is not set, a
             system dependent default value is used. It is set by test-
             ing several directories for existence when using the font-
             path the first time. Thus, the first call of [1mset fontpath[22m,
             [1mshow fontpath[22m, [1msave fontpath[22m, [1mplot[22m, or [1msplot [22mwith embedded
             font files takes a little more time. If you want to save
             this time you may set the environmental variable GNU-
             PLOT_FONTPATH since probing is switched off, then. You can
             find out which is the default fontpath by using [1mshow font-[0m
             [1mpath[22m.

             [1mshow fontpath [22mprints the contents of the user-defined
             fontpath and the system fontpath separately.  However, the
             [1msave [22mand [1msave set [22mcommands save only the user-specified
             parts of [1mfontpath[22m.

             For terminal drivers that access fonts by filename via the
             gd library, the font search path is controlled by the
             environmental variable GDFONTPATH.














   GNUPLOT 4.1                                                      158


             [1m84.23.  Format[0m


             The format of the tic-mark labels can be set with the [1mset[0m
             [1mformat [22mcommand or with the [1mset tics format [22mor individual
             [1mset {axis}tics format [22mcommands.

             Syntax:
                   set format {<axes>} {"<format-string>"}
                   set format {<axes>} {'<format-string>'}
                   show format

             where <axes> is either [1mx[22m, [1my[22m, [1mxy[22m, [1mx2[22m, [1my2[22m, [1mz[22m, [1mcb [22mor nothing
             (which applies the format to all axes). The following two
             commands are equivalent:
                   set format y "%.2f"
                   set ytics format "%.2f"

             The length of the string is restricted to 100 characters.
             The default format is "% g", but other formats such as
             "%.2f" or "%3.0em" are often desirable.  The format "$%g$"
             is often desirable for LaTeX.  If no format string is
             given, the format will be returned to the default.  If the
             empty string "" is given, tics will have no labels,
             although the tic mark will still be plotted.  To eliminate
             the tic marks, use [1munset xtics [22mor [1mset tics scale 0[22m.

             Newline (\n) and enhanced text markup is accepted in the
             format string.  Use double-quotes rather than single-
             quotes in this case.  See also [1msyntax[22m.  Characters not
             preceded by "%" are printed verbatim.  Thus you can
             include spaces and labels in your format string, such as
             "%g m", which will put " m" after each number.  If you
             want "%" itself, double it: "%g %%".

             See also [1mset xtics [22mfor more information about tic labels,
             and [1mset decimalsign [22mfor how to use non-default decimal
             separators in numbers printed this way.  See also electron
             demo (electron.dem).




                  [1m84.23.1.  Gprintf[0m


                  The string function gprintf("format",x) uses gnu-
                  plot's own format specifiers, as do the gnuplot com-
                  mands [1mset format[22m, [1mset timestamp[22m, and others. These
                  format specifiers are not the same as those used by
                  the standard C-language routine sprintf(). gprintf()
                  accepts only a single variable to be formatted.  Gnu-
                  plot also provides an sprintf("format",x1,x2,...)










   GNUPLOT 4.1                                                      159


                  routine if you prefer.  For a list of gnuplot's for-
                  mat options, see [1mformat specifiers[22m.



                  [1m84.23.2.  Format specifiers[0m


                  The acceptable formats (if not in time/date mode)
                  are:




   +-------------------------------------------------------------------------------+
   | Format    Explanation                                                         |
   +-------------------------------------------------------------------------------+
   |   %f      floating point notation                                             |
   |%e or %E   exponential notation; an "e" or "E" before the power                |
   |%g or %G   the shorter of %e (or %E) and %f                                    |
   |%x or %X   hex                                                                 |
   |%o or %O   octal                                                               |
   |   %t      mantissa to base 10                                                 |
   |   %l      mantissa to base of current logscale                                |
   |   %s      mantissa to base of current logscale; scientific power              |
   |   %T      power to base 10                                                    |
   |   %L      power to base of current logscale                                   |
   |   %S      scientific power                                                    |
   |   %c      character replacement for scientific power                          |
   |   %b      mantissa of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi) |
   |   %B      prefix of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi)   |
   |   %P      multiple of pi                                                      |
   +-------------------------------------------------------------------------------+
   +-------------------------------------------------------------------------------+




   A 'scientific' power is one such that the exponent is a multiple of
   three.  Character replacement of scientific powers ([1m"%c"[22m) has been
   implemented for powers in the range -18 to +18.  For numbers outside
   of this range the format reverts to exponential.

   Other acceptable modifiers (which come after the "%" but before the
   format specifier) are "-", which left-justifies the number; "+",
   which forces all numbers to be explicitly signed; " " (a space),
   which makes positive numbers have a space in front of them where
   negative numbers have "-"; "#", which places a decimal point after
   floats that have only zeroes following the decimal point; a positive
   integer, which defines the field width; "0" (the digit, not the let-
   ter) immediately preceding the field width, which indicates that
   leading zeroes are to be used instead of leading blanks; and a deci-
   mal point followed by a non-negative integer, which defines the










   GNUPLOT 4.1                                                      160


   precision (the minimum number of digits of an integer, or the number
   of digits following the decimal point of a float).

   Some systems may not support all of these modifiers but may also
   support others; in case of doubt, check the appropriate documenta-
   tion and then experiment.

   Examples:
         set format y "%t"; set ytics (5,10)          # "5.0" and "1.0"
         set format y "%s"; set ytics (500,1000)      # "500" and "1.0"
         set format y "%+-12.3f"; set ytics(12345)    # "+12345.000  "
         set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
         set format y "%s*10^{%S}"; set ytic(12345)   # "12.345*10^{3}"
         set format y "%s %cg"; set ytic(12345)       # "12.345 kg"
         set format y "%.0P pi"; set ytic(6.283185)   # "2 pi"
         set format y "%.0f%%"; set ytic(50)          # "50%"

         set log y 2; set format y '%l'; set ytics (1,2,3)
         #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)

   There are some problem cases that arise when numbers like 9.999 are
   printed with a format that requires both rounding and a power.

   If the data type for the axis is time/date, the format string must
   contain valid codes for the 'strftime' function (outside of [1mgnuplot[22m,
   type "man strftime").  See [1mset timefmt [22mfor a list of the allowed
   input format codes.



                  [1m84.23.3.  Time/date specifiers[0m


                  In time/date mode, the acceptable formats are:





























   GNUPLOT 4.1                                                      161


     +--------------------------------------------------------------+
     | Format    Explanation                                        |
     +--------------------------------------------------------------+
     |   %a      abbreviated name of day of the week                |
     |   %A      full name of day of the week                       |
     |%b or %h   abbreviated name of the month                      |
     |   %B      full name of the month                             |
     |   %d      day of the month, 01--31                           |
     |   %D      shorthand for "%m/%d/%y" (only output)             |
     |   %F      shorthand for "%Y-%m-%d" (only output)             |
     |   %k      hour, 0--23 (one or two digits)                    |
     |   %H      hour, 00--23 (always two digits)                   |
     |   %l      hour, 1--12 (one or two digits)                    |
     |   %I      hour, 01--12 (always two digits)                   |
     |   %j      day of the year, 1--366                            |
     |   %m      month, 01--12                                      |
     |   %M      minute, 0--60                                      |
     |   %p      "am" or "pm"                                       |
     |   %r      shorthand for "%I:%M:%S %p" (only output)          |
     |   %R      shorthand for %H:%M" (only output)                 |
     |   %S      second, integer 0--60 on output, (double) on input |
     |   %s      number of seconds since start of year 2000         |
     |   %T      shorthand for "%H:%M:%S" (only output)             |
     |   %U      week of the year (week starts on Sunday)           |
     |   %w      day of the week, 0--6 (Sunday = 0)                 |
     |   %W      week of the year (week starts on Monday)           |
     |   %y      year, 0-99 in range 1969-2068                      |
     |   %Y      year, 4-digit                                      |
     +--------------------------------------------------------------+
     +--------------------------------------------------------------+





   Except for the non-numerical formats, these may be preceded by a "0"
   ("zero", not "oh") to pad the field length with leading zeroes, and
   a positive digit, to define the minimum field width (which will be
   overridden if the specified width is not large enough to contain the
   number).  The %S format also accepts a precision specifier so that
   fractional seconds can be written.  There is a 24-character limit to
   the length of the printed text; longer strings will be truncated.

   Examples:

   Suppose the text is "76/12/25 23:11:11".  Then
         set format x                 # defaults to "12/25/76" \n
   "23:11"
         set format x "%A, %d %b %Y"  # "Saturday, 25 Dec 1976"
         set format x "%r %D"         # "11:11:11 pm 12/25/76"

   Suppose the text is "98/07/06 05:04:03.123456".  Then
         set format x "%1y/%2m/%3d %01H:%02M:%06.3S"  # "98/ 7/  6










   GNUPLOT 4.1                                                      162


   5:04:03.123"



             [1m84.24.  Function style[0m


             This form of the command is deprecated. Please see [1mset[0m
             [1mstyle function[22m.



             [1m84.25.  Functions[0m


             The [1mshow functions [22mcommand lists all user-defined func-
             tions and their definitions.

             Syntax:
                   show functions

             For information about the definition and usage of func-
             tions in [1mgnuplot[22m, please see [1mexpressions[22m.  See also
             splines as user defined functions (spline.dem) and use of
             functions and complex variables for airfoils (air-
             foil.dem).



             [1m84.26.  Grid[0m


             The [1mset grid [22mcommand allows grid lines to be drawn on the
             plot.

             Syntax:
                   set grid {{no}{m}xtics} {{no}{m}ytics}
             {{no}{m}ztics}
                            {{no}{m}x2tics} {{no}{m}y2tics}
                            {{no}{m}cbtics}
                            {polar {<angle>}}
                            {layerdefault | front | back}
                            { {linestyle <major_linestyle>}
                              | {linetype | lt <major_linetype>}
                                {linewidth | lw <major_linewidth>}
                              { , {linestyle | ls <minor_linestyle>}
                                  | {linetype | lt <minor_linetype>}
                                    {linewidth | lw <minor_linewidth>}
             } }
                   unset grid
                   show grid

             The grid can be enabled and disabled for the major and/or










   GNUPLOT 4.1                                                      163


             minor tic marks on any axis, and the linetype and
             linewidth can be specified for major and minor grid lines,
             also via a predefined linestyle, as far as the active ter-
             minal driver supports this.

             Additionally, a polar grid can be selected for 2D
             plots---circles are drawn to intersect the selected tics,
             and radial lines are drawn at definable intervals.  (The
             interval is given in degrees or radians, depending on the
             [1mset angles [22msetting.)  Note that a polar grid is no longer
             automatically generated in polar mode.

             The pertinent tics must be enabled before [1mset grid [22mcan
             draw them; [1mgnuplot [22mwill quietly ignore instructions to
             draw grid lines at non-existent tics, but they will appear
             if the tics are subsequently enabled.

             If no linetype is specified for the minor gridlines, the
             same linetype as the major gridlines is used.  The default
             polar angle is 30 degrees.

             If [1mfront [22mis given, the grid is drawn on top of the graphed
             data. If [1mback [22mis given, the grid is drawn underneath the
             graphed data. Using [1mfront [22mwill prevent the grid from being
             obscured by dense data. The default setup, [1mlayerdefault[22m,
             is equivalent to [1mback [22mfor 2D plots.  In 3D plots the
             default is to split up the grid and the graph box into two
             layers: one behind, the other in front of the plotted data
             and functions. Since [1mhidden3d [22mmode does its own sorting,
             it ignores all grid drawing order options and passes the
             grid lines through the hidden line removal machinery
             instead. These options actually affect not only the grid,
             but also the lines output by [1mset border [22mand the various
             ticmarks (see [1mset xtics[22m).

             Z grid lines are drawn on the bottom of the plot.  This
             looks better if a partial box is drawn around the
             plot---see [1mset border[22m.



             [1m84.27.  Hidden3d[0m


             The [1mset hidden3d [22mcommand enables hidden line removal for
             surface plotting (see [1msplot[22m).  Some optional features of
             the underlying algorithm can also be controlled using this
             command.

             Syntax:
                   set hidden3d {defaults} |
                                { {front|back}
                                  {{offset <offset>} | {nooffset}}










   GNUPLOT 4.1                                                      164


                                  {trianglepattern <bitpattern>}
                                  {{undefined <level>} | {noundefined}}
                                  {{no}altdiagonal}
                                  {{no}bentover} }
                   unset hidden3d
                   show hidden3d

             In contrast to the usual display in gnuplot, hidden line
             removal actually treats the given function or data grids
             as real surfaces that can't be seen through, so plot ele-
             ments behind the surface will be hidden by it.  For this
             to work, the surface needs to have 'grid structure' (see
             [1msplot datafile [22mabout this), and it has to be drawn [1mwith[0m
             [1mlines [22mor [1mwith linespoints[22m.

             When [1mhidden3d [22mis set, both the hidden portion of the sur-
             face and possibly its contours drawn on the base (see [1mset[0m
             [1mcontour[22m) as well as the grid will be hidden.  Each surface
             has its hidden parts removed with respect to itself and to
             other surfaces, if more than one surface is plotted.  Con-
             tours drawn on the surface ([1mset contour surface[22m) don't
             work.

             Labels and arrows are always visible and are unaffected.
             The key box is never hidden by the surface. As of gnuplot
             version 4.6, hidden3d also affects 3D plotting styles
             [1mpoints[22m, [1mlabels[22m, [1mvectors[22m, and [1mimpulses [22meven if no surface
             is present in the graph.  Individual plots within the
             graph may be explicitly excluded from this processing by
             appending the extra option [1mnohidden3d [22mto the [1mwith [22mspeci-
             fier.

             Hidden3d does not affect solid surfaces drawn using the
             pm3d mode. To achieve a similar effect purely for pm3d
             surfaces, use instead [1mset pm3d depthorder[22m.  To mix pm3d
             surfaces with normal [1mhidden3d [22mprocessing, use the option
             [1mset hidden3d front [22mto force all elements included in hid-
             den3d processing to be drawn after any remaining plot ele-
             ments. Then draw the surface twice, once [1mwith lines lt -2[0m
             and a second time [1mwith pm3d[22m. The first instance will
             include the surface during calculation of occluded ele-
             ments but will not draw the surface itself.

             Functions are evaluated at isoline intersections.  The
             algorithm interpolates linearly between function points or
             data points when determining the visible line segments.
             This means that the appearance of a function may be dif-
             ferent when plotted with [1mhidden3d [22mthan when plotted with
             [1mnohidden3d [22mbecause in the latter case functions are evalu-
             ated at each sample.  Please see [1mset samples [22mand [1mset[0m
             [1misosamples [22mfor discussion of the difference.

             The algorithm used to remove the hidden parts of the










   GNUPLOT 4.1                                                      165


             surfaces has some additional features controllable by this
             command.  Specifying [1mdefaults [22mwill set them all to their
             default settings, as detailed below.  If [1mdefaults [22mis not
             given, only explicitly specified options will be influ-
             enced: all others will keep their previous values, so you
             can turn on/off hidden line removal via [1mset {no}hidden3d[22m,
             without modifying the set of options you chose.

             The first option, [1moffset[22m, influences the linetype used for
             lines on the 'back' side.  Normally, they are drawn in a
             linetype one index number higher than the one used for the
             front, to make the two sides of the surface distinguish-
             able.  You can specify a different linetype offset to add
             instead of the default 1, by [1moffset <offset>[22m.  Option
             [1mnooffset [22mstands for [1moffset 0[22m, making the two sides of the
             surface use the same linetype.

             Next comes the option [1mtrianglepattern <bitpattern>[22m.  <bit-
             pattern> must be a number between 0 and 7, interpreted as
             a bit pattern.  Each bit determines the visibility of one
             edge of the triangles each surface is split up into.  Bit
             0 is for the 'horizontal' edges of the grid, Bit 1 for the
             'vertical' ones, and Bit 2 for the diagonals that split
             each cell of the original grid into two triangles.  The
             default pattern is 3, making all horizontal and vertical
             lines visible, but not the diagonals.  You may want to
             choose 7 to see those diagonals as well.

             The [1mundefined <level> [22moption lets you decide what the
             algorithm is to do with data points that are undefined
             (missing data, or undefined function values), or exceed
             the given x-, y- or z-ranges.  Such points can either be
             plotted nevertheless, or taken out of the input data set.
             All surface elements touching a point that is taken out
             will be taken out as well, thus creating a hole in the
             surface.  If <level> = 3, equivalent to option [1mnounde-[0m
             [1mfined[22m, no points will be thrown away at all.  This may
             produce all kinds of problems elsewhere, so you should
             avoid this.  <level> = 2 will throw away undefined points,
             but keep the out-of-range ones.  <level> = 1, the default,
             will get rid of out-of-range points as well.

             By specifying [1mnoaltdiagonal[22m, you can override the default
             handling of a special case can occur if [1mundefined [22mis
             active (i.e. <level> is not 3).  Each cell of the grid-
             structured input surface will be divided in two triangles
             along one of its diagonals.  Normally, all these diagonals
             have the same orientation relative to the grid.  If
             exactly one of the four cell corners is excluded by the
             [1mundefined [22mhandler, and this is on the usual diagonal, both
             triangles will be excluded.  However if the default set-
             ting of [1maltdiagonal [22mis active, the other diagonal will be
             chosen for this cell instead, minimizing the size of the










   GNUPLOT 4.1                                                      166


             hole in the surface.

             The [1mbentover [22moption controls what happens to another spe-
             cial case, this time in conjunction with the [1mtrianglepat-[0m
             [1mtern[22m.  For rather crumply surfaces, it can happen that the
             two triangles a surface cell is divided into are seen from
             opposite sides (i.e. the original quadrangle is 'bent
             over'), as illustrated in the following ASCII art:

                                                                           C----B
                 original quadrangle:  A--B      displayed quadrangle:
             |\   |
                   ("set view 0,0")    | /|    ("set view 75,75" per-
             haps)  | \  |
                                       |/ |
             |  \ |
                                       C--D
             |   \|
                                                                           A
             D

             If the diagonal edges of the surface cells aren't gener-
             ally made visible by bit 2 of the <bitpattern> there, the
             edge CB above wouldn't be drawn at all, normally, making
             the resulting display hard to understand.  Therefore, the
             default option of [1mbentover [22mwill turn it visible in this
             case.  If you don't want that, you may choose [1mnobentover[0m
             instead.  See also hidden line removal demo (hidden.dem)
             and complex hidden line demo (singulr.dem).



             [1m84.28.  Historysize[0m


             Note: the command [1mset historysize [22mis only available when
             gnuplot has been configured to use the GNU readline
             library.

             Syntax:
                   set historysize <int>
                   unset historysize

             When leaving gnuplot, the value of historysize is used for
             truncating the history to at most that much lines. The
             default is 500.  [1munset historysize [22mwill disable history
             truncation and thus allow an infinite number of lines to
             be written to the history file.















   GNUPLOT 4.1                                                      167


             [1m84.29.  Isosamples[0m


             The isoline density (grid) for plotting functions as sur-
             faces may be changed by the [1mset isosamples [22mcommand.

             Syntax:
                   set isosamples <iso_1> {,<iso_2>}
                   show isosamples

             Each function surface plot will have <iso_1> iso-u lines
             and <iso_2> iso-v lines.  If you only specify <iso_1>,
             <iso_2> will be set to the same value as <iso_1>.  By
             default, sampling is set to 10 isolines per u or v axis.
             A higher sampling rate will produce more accurate plots,
             but will take longer.  These parameters have no effect on
             data file plotting.

             An isoline is a curve parameterized by one of the surface
             parameters while the other surface parameter is fixed.
             Isolines provide a simple means to display a surface.  By
             fixing the u parameter of surface s(u,v), the iso-u lines
             of the form c(v) = s(u0,v) are produced, and by fixing the
             v parameter, the iso-v lines of the form c(u) = s(u,v0)
             are produced.

             When a function surface plot is being done without the
             removal of hidden lines, [1mset samples  [22mcontrols the number
             of points sampled along each isoline;  see [1mset samples [22mand
             [1mset hidden3d[22m. The contour algorithm assumes that a func-
             tion sample occurs at each isoline intersection, so change
             in [1msamples [22mas well as [1misosamples [22mmay be desired when
             changing the resolution of a function surface/contour.



             [1m84.30.  Key[0m


             The [1mset key [22mcommand enables a key (or legend) describing
             plots on a plot.

             The contents of the key, i.e., the names given to each
             plotted data set and function and samples of the lines
             and/or symbols used to represent them, are determined by
             the [1mtitle [22mand [1mwith [22moptions of the {[1ms[22m}[1mplot [22mcommand.  Please
             see [1mplot title [22mand [1mplot with [22mfor more information.

             Syntax:
                   set key {on|off} {default}
                           {{inside | outside} | {lmargin | rmargin |
             tmargin | bmargin}
                             | {at <position>}}










   GNUPLOT 4.1                                                      168


                           {left | right | center} {top | bottom | cen-
             ter}
                           {vertical | horizontal} {Left | Right}
                           {{no}opaque}
                           {{no}reverse} {{no}invert}
                           {samplen <sample_length>} {spacing <verti-
             cal_spacing>}
                           {width <width_increment>}
                           {height <height_increment>}
                           {{no}autotitle {columnheader}}
                           {title "<text>"} {{no}enhanced}
                           {font "<face>,<size>"} {textcolor <color-
             spec>}
                           {{no}box { {linestyle | ls <line_style>}
                                      | {linetype | lt <line_type>}
                                        {linewidth | lw <line_width>}}}
                           {maxcols {<max no. of columns> | auto}}
                           {maxrows {<max no. of rows> | auto}}
                   unset key
                   show key

             The key contains a title and a sample (line, point, box)
             for each plot in the graph. The key may be turned off by
             requesting [1mset key off [22mor [1munset key[22m.  Individual key
             entries may be turned off by using the [1mnotitle [22mkeyword in
             the corresponding plot command.

             Elements within the key are stacked according to [1mvertical[0m
             or [1mhorizontal[22m.  In the case of [1mvertical[22m, the key occupies
             as few columns as possible.  That is, elements are aligned
             in a column until running out of vertical space at which
             point a new column is started.  The vertical space may be
             limited using 'maxrows'.  In the case of [1mhorizontal[22m, the
             key occupies as few rows as possible.  The horizontal
             space may be limited using 'maxcols'.

             By default the key is placed in the upper right inside
             corner of the graph.  The keywords [1mleft[22m, [1mright[22m, [1mtop[22m, [1mbot-[0m
             [1mtom[22m, [1mcenter[22m, [1minside[22m, [1moutside[22m, [1mlmargin[22m, [1mrmargin[22m, [1mtmargin[22m,
             [1mbmargin [22m(, [1mabove[22m, [1mover[22m, [1mbelow [22mand [1munder[22m) may be used to
             automatically place the key in other positions of the
             graph.  Also an [1mat <position> [22mmay be given to indicate
             precisely where the plot should be placed.  In this case,
             the keywords [1mleft[22m, [1mright[22m, [1mtop[22m, [1mbottom [22mand [1mcenter [22mserve an
             analogous purpose for alignment.  For more information,
             see [1mkey placement[22m.

             Justification of the plot titles within the key is con-
             trolled by [1mLeft [22mor [1mRight [22m(default).  The text and sample
             can be reversed ([1mreverse[22m) and a box can be drawn around
             the key ([1mbox {...}[22m) in a specified [1mlinetype [22mand [1mlinewidth[22m,
             or a user-defined [1mlinestyle[22m.











   GNUPLOT 4.1                                                      169


             By default the key is built up one plot at a time. That
             is, the key symbol and title are drawn at the same time as
             the corresponding plot.  That means newer plots may some-
             times place elements on top of the key.  [1mset key opaque[0m
             causes the key to be generated after all the plots.  In
             this case the key area is filled with background color and
             then the key symbols and titles are written.  Therefore
             the key itself may obscure portions of some plot elements.
             The default can be restored by [1mset key noopaque[22m.

             By default the first plot label is at the top of the key
             and successive labels are entered below it. The [1minvert[0m
             option causes the first label to be placed at the bottom
             of the key, with successive labels entered above it. This
             option is useful to force the vertical ordering of labels
             in the key to match the order of box types in a stacked
             histogram.

             The <height_increment> is a number of character heights to
             be added to or subtracted from the height of the key box.
             This is useful mainly when you are putting a box around
             the key and want larger borders around the key entries.

             All plotted curves of [1mplot[22ms and [1msplot[22ms are titled accord-
             ing to the default option [1mautotitles[22m. The automatic gener-
             ation of titles can be suppressed by [1mnoautotitles[22m; then
             only those titles explicitly defined by [1m(s)plot ... title[0m
             [1m... [22mwill be drawn.

             The command [1mset key autotitle columnheader [22mcauses the
             first entry in each column of input data to be interpreted
             as a text string and used as a title for the corresponding
             plot. If the quantity being plotted is a function of data
             from several columns, gnuplot may be confused as to which
             column to draw the title from. In this case it is neces-
             sary to specify the column explicitly in the plot command,
             e.g.

                   plot "datafile" using (($2+$3)/$4) title column-
             head(3) with lines

             An overall title can be put on the key ([1mtitle[0m
             [1m"<text>"[22m)---see also [1msyntax [22mfor the distinction between
             text in single- or double-quotes.  The key title uses the
             same justification as do the plot titles.

             The defaults for [1mset key [22mare [1mon[22m, [1mright[22m, [1mtop[22m, [1mvertical[22m,
             [1mRight[22m, [1mnoreverse[22m, [1mnoinvert[22m, [1msamplen 4[22m, [1mspacing 1.25[22m, [1mtitle[0m
             [1m""[22m, and [1mnobox[22m.  The default <linetype> is the same as that
             used for the plot borders.  Entering [1mset key default[0m
             returns the key to its default configuration.

             The key is drawn as a sequence of lines, with one plot










   GNUPLOT 4.1                                                      170


             described on each line.  On the right-hand side (or the
             left-hand side, if [1mreverse [22mis selected) of each line is a
             representation that attempts to mimic the way the curve is
             plotted.  On the other side of each line is the text
             description (the line title), obtained from the [1mplot [22mcom-
             mand.  The lines are vertically arranged so that an imagi-
             nary straight line divides the left- and right-hand sides
             of the key.  It is the coordinates of the top of this line
             that are specified with the [1mset key [22mcommand.  In a [1mplot[22m,
             only the x and y coordinates are used to specify the line
             position.  For a [1msplot[22m, x, y and z are all used as a 3D
             location mapped using the same mapping as the graph itself
             to form the required 2D screen position of the imaginary
             line.

             When using the TeX or other terminals where formatting
             information is embedded in the string, [1mgnuplot [22mcan only
             estimate the correctly exact width of the string for key
             positioning.  If the key is to be positioned at the left,
             it may be convenient to use the combination  [1mset key left[0m
             [1mLeft reverse[22m.

             If [1msplot [22mis being used to draw contours, the contour
             labels will be listed in the key.  If the alignment of
             these labels is poor or a different number of decimal
             places is desired, the label format can be specified.  See
             [1mset clabel [22mfor details.

             Examples:

             This places the key at the default location:
                   set key default

             This disables the key:
                   unset key

             This places a key at coordinates 2,3.5,2 in the default
             (first) coordinate system:
                   set key at 2,3.5,2

             This places the key below the graph:
                   set key below

             This places the key in the bottom left corner, left-justi-
             fies the text, gives it a title, and draws a box around it
             in linetype 3:
                   set key left bottom Left title 'Legend' box 3
















   GNUPLOT 4.1                                                      171


                  [1m84.30.1.  Key placement[0m


                  To understand positioning, the best concept is to
                  think of a region, i.e., inside/outside, or one of
                  the margins.  Along with the region, keywords
                  [1mleft/center/right [22m(l/c/r) and [1mtop/center/bottom[0m
                  (t/c/b) control where within the particular region
                  the key should be placed.

                  When in [1minside [22mmode, the keywords [1mleft [22m(l), [1mright[0m
                  (r), [1mtop [22m(t), [1mbottom [22m(b), and [1mcenter [22m(c) push the key
                  out toward the plot boundary as illustrated:

                       t/l   t/c   t/r

                       c/l    c    c/r

                       b/l   b/c   b/r


                  When in [1moutside [22mmode, automatic placement is similar
                  to the above illustration, but with respect to the
                  view, rather than the graph boundary.  That is, a
                  border is moved inward to make room for the key out-
                  side of the plotting area, although this may inter-
                  fere with other labels and may cause an error on some
                  devices.  The particular plot border that is moved
                  depends upon the position described above and the
                  stacking direction.  For options centered in one of
                  the dimensions, there is no ambiguity about which
                  border to move.  For the corners, when the stack
                  direction is [1mvertical[22m, the left or right border is
                  moved inward appropriately.  When the stack direction
                  is [1mhorizontal[22m, the top or bottom border is moved
                  inward appropriately.

                  The margin syntax allows automatic placement of key
                  regardless of stack direction.  When one of the mar-
                  gins [1mlmargin [22m(lm), [1mrmargin [22m(rm), [1mtmargin [22m(tm), and
                  [1mbmargin [22m(bm) is combined with a single, non-conflict-
                  ing direction keyword, the following illustrated
                  positions may contain the key:

                            l/tm  c/tm  r/tm

                       t/lm                  t/rm

                       c/lm                  c/rm

                       b/lm                  b/rm

                            l/bm  c/bm  r/bm










   GNUPLOT 4.1                                                      172


                  Keywords [1mabove [22mand [1mover [22mare synonymous with [1mtmargin[22m.
                  For version compatibility, [1mabove [22mor [1mover [22mwithout an
                  additional l/c/r or stack direction keyword uses [1mcen-[0m
                  [1mter [22mand [1mhorizontal[22m.  Keywords [1mbelow [22mand [1munder [22mare
                  synonymous with [1mbmargin[22m.  For compatibility, [1mbelow [22mor
                  [1munder [22mwithout an additional l/c/r or stack  direction
                  keyword uses [1mcenter [22mand [1mhorizontal[22m.  A further com-
                  patibility issue is that [1moutside [22mappearing without an
                  additional t/b/c or stack direction keyword uses [1mtop[22m,
                  [1mright [22mand [1mvertical [22m(i.e., the same as t/rm above).

                  The <position> can be a simple x,y,z as in previous
                  versions, but these can be preceded by one of five
                  keywords ([1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, [1mcharacter[22m)
                  which selects the coordinate system in which the
                  position of the first sample line is specified.  See
                  [1mcoordinates [22mfor more details.  The effect of [1mleft[22m,
                  [1mright[22m, [1mtop[22m, [1mbottom[22m, and [1mcenter [22mwhen <position> is
                  given is to align the key as though it were text
                  positioned using the label command, i.e., [1mleft [22mmeans
                  left align with key to the right of <position>, etc.



                  [1m84.30.2.  Key samples[0m


                  By default, each plot on the graph generates a corre-
                  sponding entry in the key.  This entry contains a
                  plot title and a sample line/point/box of the same
                  color and fill properties as used in the plot itself.
                  The font and textcolor properties control the appear-
                  ance of the individual plot titles that appear in the
                  key. Setting the textcolor to "variable" causes the
                  text for each key entry to be the same color as the
                  line or fill color for that plot.  This was the
                  default in some earlier versions of gnuplot.

                  The length of the sample line can be controlled by
                  [1msamplen[22m.  The sample length is computed as the sum of
                  the tic length and <sample_length> times the charac-
                  ter width.  [1msamplen [22malso affects the positions of
                  point samples in the key since these are drawn at the
                  midpoint of the sample line, even if the sample line
                  itself is not drawn.

                  The vertical spacing between lines is controlled by
                  [1mspacing[22m.  The spacing is set equal to the product of
                  the pointsize, the vertical tic size, and <verti-
                  cal_spacing>.  The program will guarantee that the
                  vertical spacing is no smaller than the character
                  height.











   GNUPLOT 4.1                                                      173


                  The <width_increment> is a number of character widths
                  to be added to or subtracted from the length of the
                  string.  This is useful only when you are putting a
                  box around the key and you are using control charac-
                  ters in the text.  [1mgnuplot [22msimply counts the number
                  of characters in the string when computing the box
                  width; this allows you to correct it.



             [1m84.31.  Label[0m


             Arbitrary labels can be placed on the plot using the [1mset[0m
             [1mlabel [22mcommand.

             Syntax:
                   set label {<tag>} {"<label text>"} {at <position>}
                             {left | center | right}
                             {norotate | rotate {by <degrees>}}
                             {font "<name>{,<size>}"}
                             {noenhanced}
                             {front | back}
                             {textcolor <colorspec>}
                             {point <pointstyle> | nopoint}
                             {offset <offset>}
                   unset label {<tag>}
                   show label

             The <position> is specified by either x,y or x,y,z, and
             may be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mchar-[0m
             [1macter [22mto select the coordinate system.  See [1mcoordinates[0m
             for details.

             The tag is an integer that is used to identify the label.
             If no <tag> is given, the lowest unused tag value is
             assigned automatically.  The tag can be used to delete or
             modify a specific label.  To change any attribute of an
             existing label, use the [1mset label [22mcommand with the appro-
             priate tag, and specify the parts of the label to be
             changed.

             The <label text> can be a string constant, a string vari-
             able, or a string- valued expression. See [1mstrings[22m,
             [1msprintf[22m, and [1mgprintf[22m.

             By default, the text is placed flush left against the
             point x,y,z.  To adjust the way the label is positioned
             with respect to the point x,y,z, add the justification
             parameter, which may be [1mleft[22m, [1mright [22mor [1mcenter[22m, indicating
             that the point is to be at the left, right or center of
             the text.  Labels outside the plotted boundaries are per-
             mitted but may interfere with axis labels or other text.










   GNUPLOT 4.1                                                      174


             If [1mrotate [22mis given, the label is written vertically (if
             the terminal can do so, of course).  If [1mrotate by[0m
             [1m<degrees> [22mis given, conforming terminals will try to write
             the text at the specified angle; non-conforming terminals
             will treat this as vertical text.

             Font and its size can be chosen explicitly by [1mfont[0m
             [1m"<name>{,<size>}" [22mif the terminal supports font settings.
             Otherwise the default font of the terminal will be used.

             Normally the enhanced text mode string interpretation, if
             enabled for the current terminal, is applied to all text
             strings including label text.  The [1mnoenhanced [22mproperty can
             be used to exempt a specific label from the enhanced text
             mode processing.  The can be useful if the label contains
             underscores, for example. See [1menhanced text[22m.

             If [1mfront [22mis given, the label is written on top of the
             graphed data. If [1mback [22mis given (the default), the label is
             written underneath the graphed data.  Using [1mfront [22mwill
             prevent a label from being obscured by dense data.

             [1mtextcolor <colorspec> [22mchanges the color of the label text.
             <colorspec> can be a linetype, an rgb color, or a palette
             mapping. See help for [1mcolorspec [22mand [1mpalette[22m.  [1mtextcolor[0m
             may be abbreviated [1mtc[22m.
                `tc default` resets the text color to its default
             state.
                `tc lt <n>` sets the text color to that of line type
             <n>.
                `tc ls <n>` sets the text color to that of line style
             <n>.
                `tc palette z` selects a palette color corresponding to
             the label z position.
                `tc palette cb <val>` selects a color corresponding to
             <val> on the colorbar.
                `tc palette fraction <val>`, with 0<=val<=1, selects a
             color corresponding to
                    the mapping [0:1] to grays/colors of the `palette`.
                `tc rgb "#RRGGBB"` selects an arbitrary 24-bit RGB
             color.

             If a <pointstyle> is given, using keywords [1mlt[22m, [1mpt [22mand [1mps[22m,
             see [1mstyle[22m, a point with the given style and color of the
             given line type is plotted at the label position and the
             text of the label is displaced slightly.  This option is
             used by default for placing labels in [1mmouse [22menhanced ter-
             minals.  Use [1mnopoint [22mto turn off the drawing of a point
             near the label (this is the default).

             The displacement defaults to 1,1 in [1mpointsize [22munits if a
             <pointstyle> is given, 0,0 if no <pointstyle> is given.
             The displacement can be controlled by the optional [1moffset[0m










   GNUPLOT 4.1                                                      175


             [1m<offset> [22mwhere <offset> is specified by either x,y or
             x,y,z, and may be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m,
             [1mscreen[22m, or [1mcharacter [22mto select the coordinate system.  See
             [1mcoordinates [22mfor details.

             If one (or more) axis is timeseries, the appropriate coor-
             dinate should be given as a quoted time string according
             to the [1mtimefmt [22mformat string.  See [1mset xdata [22mand [1mset[0m
             [1mtimefmt[22m.

             The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a
             string to specify a newline.

             Label coordinates and text can also be read from a data
             file (see [1mlabels[22m).

             Examples:

             To set a label at (1,2) to "y=x", use:
                   set label "y=x" at 1,2

             To set a Sigma of size 24, from the Symbol font set, at
             the center of the graph, use:
                   set label "S" at graph 0.5,0.5 center font "Sym-
             bol,24"

             To set a label "y=x^2" with the right of the text at
             (2,3,4), and tag the label as number 3, use:
                   set label 3 "y=x^2" at 2,3,4 right

             To change the preceding label to center justification,
             use:
                   set label 3 center

             To delete label number 2, use:
                   unset label 2

             To delete all labels, use:
                   unset label

             To show all labels (in tag order), use:
                   show label

             To set a label on a graph with a timeseries on the x axis,
             use, for example:
                   set timefmt "%d/%m/%y,%H:%M"
                   set label "Harvest" at "25/8/93",1

             To display a freshly fitted parameter on the plot with the
             data and the fitted function, do this after the [1mfit[22m, but
             before the [1mplot[22m:
                   set label sprintf("a = %3.5g",par_a) at 30,15
                   bfit = gprintf("b = %s*10^%S",par_b)










   GNUPLOT 4.1                                                      176


                   set label bfit at 30,20

             To display a function definition along with its fitted
             parameters, use:
                   f(x)=a+b*x
                   fit f(x) 'datafile' via a,b
                   set label GPFUN_f at graph .05,.95
                   set label sprintf("a = %g", a) at graph .05,.90
                   set label sprintf("b = %g", b) at graph .05,.85

             To set a label displaced a little bit from a small point:
                   set label 'origin' at 0,0 point lt 1 pt 2 ps 3 off-
             set 1,-1

             To set a label whose color matches the z value (in this
             case 5.5) of some point on a 3D splot colored using pm3d:
                   set label 'text' at 0,0,5.5 tc palette z



             [1m84.32.  Linetype[0m


             The [1mset linetype [22mcommand allows you to redefine the basic
             linetypes used for plots.  The command options are identi-
             cal to those for "set style line".  Unlike line styles,
             redefinitions by [1mset linetype [22mare persistent;  they are
             not affected by [1mreset[22m.

             For example, linetypes one and two default to red and
             green. If you redefine them like this:

                   set linetype 1 lw 2 lc rgb "blue" pointtype 6
                   set linetype 2 lw 2 lc rgb "forest-green" pointtype
             8

             everywhere that uses lt 1 will now get a thick blue line
             rather than a thin red line (the previous default meaning
             of lt 1).  This includes uses such as the definition of a
             temporary linestyle derived from the base linetype 1.

             [1mNote[22m: This command is new to gnuplot version 4.6.  It
             supersedes a rather cryptic command in version 4.2 "set
             style increment user".  The older command is now depre-
             cated.

             This mechanism can be used to define a set of personal
             preferences for the sequence of lines used in gnuplot.
             The recommended way to do this is to add to the run-time
             initialization file ~/.gnuplot a sequence of commands like

                   if ((GPVAL_VERSION < 4.5) \
                   ||










   GNUPLOT 4.1                                                      177


             (!strstrt(GPVAL_COMPILE_OPTIONS,"+USER_LINETYPES"))) \
                       exit
                   set linetype 1 lc rgb "dark-violet" lw 2 pt 0
                   set linetype 2 lc rgb "sea-green"   lw 2 pt 7
                   set linetype 3 lc rgb "cyan"        lw 2 pt 6 pi -1
                   set linetype 4 lc rgb "dark-red"    lw 2 pt 5 pi -1
                   set linetype 5 lc rgb "blue"        lw 2 pt 8
                   set linetype 6 lc rgb "dark-orange" lw 2 pt 3
                   set linetype 7 lc rgb "black"       lw 2 pt 11
                   set linetype 8 lc rgb "goldenrod"   lw 2
                   set linetype cycle 8

             Every time you run gnuplot the line types will be initial-
             ized to these values.  You may initialize as many line-
             types as you like. If you do not redefine, say, linetype 3
             then it will continue to have the default properties (in
             this case blue, pt 3, lw 1, etc).  The first few lines of
             the example script insure that the commands will be
             skipped by older versions of gnuplot.

             Similar script files can be used to define theme-based
             color choices, or sets of colors optimized for a particu-
             lar plot type or output device.

             The command [1mset linetype cycle 8 [22mtells gnuplot to re-use
             these definitions for the color and linewidth of higher-
             numbered linetypes.  That is, linetypes 9-16, 17-24, and
             so on will use this same sequence of colors and widths.
             The point properties (pointtype, pointsize, pointinterval)
             are not affected by this command.  [1munset linetype cycle[0m
             disables this feature.  If the line properties of a higher
             numbered linetype are explicitly defined, this takes
             precedence over the recycled low-number linetype proper-
             ties.




             [1m84.33.  Lmargin[0m


             The command [1mset lmargin [22msets the size of the left margin.
             Please see [1mset margin [22mfor details.



             [1m84.34.  Loadpath[0m


             The [1mloadpath [22msetting defines additional locations for data
             and command files searched by the [1mcall[22m, [1mload[22m, [1mplot [22mand
             [1msplot [22mcommands.  If a file cannot be found in the current
             directory, the directories in [1mloadpath [22mare tried.










   GNUPLOT 4.1                                                      178


             Syntax:
                   set loadpath {"pathlist1" {"pathlist2"...}}
                   show loadpath

             Path names may be entered as single directory names, or as
             a list of path names separated by a platform-specific path
             separator, eg. colon (':') on Unix, semicolon (';') on
             DOS/Windows/OS/2 platforms.  The [1mshow loadpath[22m, [1msave [22mand
             [1msave set [22mcommands replace the platform-specific separator
             with a space character (' ').

             If the environment variable GNUPLOT_LIB is set, its con-
             tents are appended to [1mloadpath[22m.  However, [1mshow loadpath[0m
             prints the contents of [1mset loadpath [22mand GNUPLOT_LIB sepa-
             rately.  Also, the [1msave [22mand [1msave set [22mcommands ignore the
             contents of GNUPLOT_LIB.



             [1m84.35.  Locale[0m


             The [1mlocale [22msetting determines the language with which
             [1m{x,y,z}{d,m}tics [22mwill write the days and months.

             Syntax:
                   set locale {"<locale>"}

             <locale> may be any language designation acceptable to
             your installation.  See your system documentation for the
             available options.  The command [1mset locale "" [22mwill try to
             determine the locale from the LC_TIME, LC_ALL, or LANG
             environment variables.

             To change the decimal point locale, see [1mset decimalsign[22m.
             To change the character encoding to the current locale,
             see [1mset encoding[22m.



             [1m84.36.  Logscale[0m


             Syntax:
                   set logscale <axes> {<base>}
                   unset logscale <axes>
                   show logscale

             where <axes> may be any combinations of [1mx[22m, [1mx2[22m, [1my[22m, [1my2[22m, [1mz[22m,
             [1mcb[22m, and [1mr [22min any order.  <base> is the base of the log
             scaling (default is base 10).  If no axes are specified,
             the command affects all axes except [1mr[22m.  The command [1munset[0m
             [1mlogscale [22mturns off log scaling for all axes.  Note that










   GNUPLOT 4.1                                                      179


             the ticmarks generated for logscaled axes are not uni-
             formly spaced.  See [1mset xtics[22m.

             Examples:

             To enable log scaling in both x and z axes:
                   set logscale xz

             To enable scaling log base 2 of the y axis:
                   set logscale y 2

             To enable z and color log axes for a pm3d plot:
                   set logscale zcb

             To disable z axis log scaling:
                   unset logscale z



             [1m84.37.  Macros[0m


             If command line macro substitution is enabled, then tokens
             in the command line of the form @<stringvariablename> will
             be replaced by the text string contained in <stringvari-
             ablename>. See [1msubstitution[22m.

             Syntax:
                  set macros




             [1m84.38.  Mapping[0m


             If data are provided to [1msplot [22min spherical or cylindrical
             coordinates, the [1mset mapping [22mcommand should be used to
             instruct [1mgnuplot [22mhow to interpret them.

             Syntax:
                   set mapping {cartesian | spherical | cylindrical}

             A cartesian coordinate system is used by default.

             For a spherical coordinate system, the data occupy two or
             three columns (or [1musing [22mentries).  The first two are
             interpreted as the azimuthal and polar angles theta and
             phi (or "longitude" and "latitude"), in the units speci-
             fied by [1mset angles[22m.  The radius r is taken from the third
             column if there is one, or is set to unity if there is no
             third column.  The mapping is:











   GNUPLOT 4.1                                                      180


                   x = r * cos(theta) * cos(phi)
                   y = r * sin(theta) * cos(phi)
                   z = r * sin(phi)

             Note that this is a "geographic" spherical system, rather
             than a "polar" one (that is, phi is measured from the
             equator, rather than the pole).

             For a cylindrical coordinate system, the data again occupy
             two or three columns.  The first two are interpreted as
             theta (in the units specified by [1mset angles[22m) and z.  The
             radius is either taken from the third column or set to
             unity, as in the spherical case.  The mapping is:

                   x = r * cos(theta)
                   y = r * sin(theta)
                   z = z

             The effects of [1mmapping [22mcan be duplicated with the [1musing[0m
             filter on the [1msplot [22mcommand, but [1mmapping [22mmay be more con-
             venient if many data files are to be processed.  However
             even if [1mmapping [22mis used, [1musing [22mmay still be necessary if
             the data in the file are not in the required order.

             [1mmapping [22mhas no effect on [1mplot[22m.  world.dem: mapping demos.



             [1m84.39.  Margin[0m


             The [1mmargin [22mis the distance between the plot border and the
             outer edge of the canvas. The size of the margin is chosen
             automatically, but can be overridden by the [1mset margin[0m
             commands.  [1mshow margin [22mshows the current settings.  To
             alter the distance between the inside of the plot border
             and the data in the plot itself, see [1mset offsets[22m.

             Syntax:
                   set bmargin {{at screen} <margin>}
                   set lmargin {{at screen} <margin>}
                   set rmargin {{at screen} <margin>}
                   set tmargin {{at screen} <margin>}
                   show margin

             The default units of <margin> are character heights or
             widths, as appropriate.  A positive value defines the
             absolute size of the margin.  A negative value (or none)
             causes [1mgnuplot [22mto revert to the computed value.  For 3D
             plots, only the left margin can be set using character
             units.

             The keywords [1mat screen [22mindicates that the margin is










   GNUPLOT 4.1                                                      181


             specified as a fraction of the full drawing area. This can
             be used to precisely line up the corners of individual 2D
             and 3D graphs in a multiplot. This placement ignores the
             current values of [1mset origin [22mand [1mset size[22m, and is intended
             as an alternative method for positioning graphs within a
             multiplot.

             Normally the margins of a plot are automatically calcu-
             lated based on tics, tic labels, axis labels, the plot
             title, the timestamp and the size of the key if it is out-
             side the borders.  If, however, tics are attached to the
             axes ([1mset xtics axis[22m, for example), neither the tics them-
             selves nor their labels will be included in either the
             margin calculation or the calculation of the positions of
             other text to be written in the margin.  This can lead to
             tic labels overwriting other text if the axis is very
             close to the border.



             [1m84.40.  Mouse[0m


             The command [1mset mouse [22menables mouse actions for the cur-
             rent interactive terminal.  It is usually enabled by
             default in interactive mode, but disabled by default if
             commands are being read from a file.

             There are two mouse modes. The 2D mode works for [1mplot [22mcom-
             mands and for [1msplot [22mmaps (i.e. [1mset view [22mwith z-rotation 0,
             90, 180, 270 or 360 degrees, including [1mset view map[22m).  In
             this mode the mouse position is tracked and you can pan or
             zoom using the mouse buttons or arrow keys.  Some termi-
             nals support toggling individual plots on/off by clicking
             on the corresponding key title or on a separate widget.

             For 3D graphs [1msplot[22m, the view and scaling of the graph can
             be changed with mouse buttons 1 and 2, respectively. A
             vertical motion of Button 2 with the shift key held down
             changes the [1mxyplane[22m.  If additionally to these buttons the
             modifier <ctrl> is held down, the coordinate axes are dis-
             played but the data are suppressed.  This is useful for
             large data sets.

             Mousing is not available inside multiplot mode. When mul-
             tiplot is completed using [1munset multiplot[22m, then the mouse
             will be turned on again but acts only on the most recent
             plot within the multiplot (like replot does).

             Syntax:
                   set mouse {doubleclick <ms>} {nodoubleclick} \
                             {{no}zoomcoordinates} \
                             {noruler | ruler {at x,y}} \










   GNUPLOT 4.1                                                      182


                             {polardistance{deg|tan} | nopolardistance}
             \
                             {format <string>} \
                             {clipboardformat <int>/<string>} \
                             {mouseformat <int>/<string>} \
                             {{no}labels {"labeloptions"}} \
                             {{no}zoomjump} {{no}verbose}
                   unset mouse

             The options [1mnoruler [22mand [1mruler [22mswitch the ruler off and on,
             the latter optionally setting the origin at the given
             coordinates. While the ruler is on, the distance in user
             units from the ruler origin to the mouse is displayed con-
             tinuously. By default, toggling the ruler has the key
             binding 'r'.

             The option [1mpolardistance [22mdetermines if the distance
             between the mouse cursor and the ruler is also shown in
             polar coordinates (distance and angle in degrees or tan-
             gent (slope)). This corresponds to the default key binding
             '5'.

             Choose the option [1mlabels [22mto define persistent gnuplot
             labels using Button 2.  The default is [1mnolabels[22m, which
             makes Button 2 draw only a temporary label at the mouse
             position. Labels are drawn with the current setting of
             [1mmouseformat[22m.  The [1mlabeloptions [22mstring is passed to the [1mset[0m
             [1mlabel [22mcommand.  The default is "point pointstyle 1" which
             will plot a small plus at the label position.  Temporary
             labels will disappear at the next [1mreplot [22mor mouse zoom
             operation.  Persistent labels can be removed by holding
             the Ctrl-Key down while clicking Button 2 on the label's
             point. The threshold for how close you must be to the
             label is also determined by the [1mpointsize[22m.

             If the option [1mverbose [22mis turned on the communication com-
             mands are shown during execution. This option can also be
             toggled by hitting [1m6 [22min the driver's window. [1mverbose [22mis
             off by default.

             Press 'h' in the driver's window for a short summary of
             the mouse and key bindings.  This will also display user
             defined bindings or [1mhotkeys [22mwhich can be defined using the
             [1mbind [22mcommand, see help for [1mbind[22m.  Note, that user defined
             [1mhotkeys [22mmay override the default bindings.  See also help
             for [1mbind [22mand [1mlabel[22m.

















   GNUPLOT 4.1                                                      183


                  [1m84.40.1.  Doubleclick[0m


                  The doubleclick resolution is given in milliseconds
                  and used for Button 1, which copies the current mouse
                  position to the [1mclipboard[22m.  The default value is 300
                  ms.  Setting the value to 0 ms triggers the copy on a
                  single click.



                  [1m84.40.2.  Mouseformat[0m


                  The [1mset mouse format [22mcommand specifies a format
                  string for sprintf() which determines how the mouse
                  cursor [x,y] coordinates are printed to the plot win-
                  dow and to the clipboard.  The default is "% #g".

                  [1mset mouse clipboardformat [22mand [1mset mouse mouseformat[0m
                  are used for formatting the text on Button1 and But-
                  ton2 actions -- copying the coordinates to the clip-
                  board and temporarily annotating the mouse position.
                  An integer argument selects one of the format options
                  in the table below. A string argument is used as a
                  format for sprintf() in option 6 and should contain
                  two float specifiers.  Example:
                       `set mouse mouseformat "mouse x,y = %5.2g,
                  %10.3f"`.
                  Use [1mset mouse mouseformat "" [22mto turn this string off
                  again.

                  The following formats are available:

                   0   default (same as 1)
                   1   axis coordinates                    1.23, 2.45
                   2   graph coordinates (from 0 to 1)    /0.00, 1.00/
                   3   x = timefmt     y = axis           [(as set by
                  `set timefmt`), 2.45]
                   4   x = date        y = axis           [31. 12.
                  1999, 2.45]
                   5   x = time        y = axis           [23:59, 2.45]
                   6   x = date time   y = axis           [31. 12. 1999
                  23:59, 2.45]
                   7   format from `set mouse mouseformat`, e.g. "mouse
                  x,y = 1.23,     2.450"



                  [1m84.40.3.  Scrolling[0m













   GNUPLOT 4.1                                                      184


                  X and Y axis scaling in both 2D and 3D graphs can be
                  adjusted using the mouse wheel.  <wheel-up> scrolls
                  up (increases both YMIN and YMAX by ten percent of
                  the Y range, and increases both Y2MIN and Y2MAX like-
                  wise), and <wheel down> scrolls down.  <shift-wheel-
                  up> scrolls left (decreases both XMIN and XMAX, and
                  both X2MIN and X2MAX), and <shift-wheel-down> scrolls
                  right.  <control-wheel-up> zooms in toward the center
                  of the plot, and <control-wheel-down> zooms out.
                  <shift-control-wheel-up> zooms in along the X and X2
                  axes only, and <shift-control-wheel-down> zooms out
                  along the X and X2 axes only.



                  [1m84.40.4.  X11 mouse[0m


                  If multiple X11 plot windows have been opened using
                  the [1mset term x11 <n> [22mterminal option, then only the
                  current plot window supports the entire range of
                  mouse commands and hotkeys.  The other windows will,
                  however, continue to display mouse coordinates at the
                  lower left.



                  [1m84.40.5.  Zoom[0m


                  Zooming is usually accomplished by holding down the
                  left mouse button and dragging the mouse to delineate
                  a zoom region.  Some platforms may require using a
                  different mouse button.  The original plot can be
                  restored by typing the 'u' hotkey in the plot window.
                  The hotkeys 'p' and 'n' step back and forth through a
                  history of zoom operations.

                  The option [1mzoomcoordinates [22mdetermines if the coordi-
                  nates of the zoom box are drawn at the edges while
                  zooming. This is on by default.

                  If the option [1mzoomjump [22mis on, the mouse pointer will
                  be automatically offset a small distance after start-
                  ing a zoom region with button 3. This can be useful
                  to avoid a tiny (or even empty) zoom region. [1mzoomjump[0m
                  is off by default.
















   GNUPLOT 4.1                                                      185


             [1m84.41.  Multiplot[0m


             The command [1mset multiplot [22mplaces [1mgnuplot [22min the multiplot
             mode, in which several plots are placed on the same page,
             window, or screen.

             Syntax:
                   set multiplot
                       { title <page title> {font <fontspec>}
             {enhanced|noenhanced} }
                       { layout <rows>,<cols>
                         {rowsfirst|columnsfirst} {downwards|upwards}
                         {scale <xscale>{,<yscale>}} {offset
             <xoff>{,<yoff>}}
                       }
                   unset multiplot

             For some terminals, no plot is displayed until the command
             [1munset multiplot [22mis given, which causes the entire page to
             be drawn and then returns gnuplot to its normal single-
             plot mode.  For other terminals, each separate [1mplot [22mcom-
             mand produces an updated display, either by redrawing all
             previous ones and the newly added plot, or by just adding
             the new plot to the existing display.

             The area to be used by the next plot is not erased before
             doing the new plot.  The [1mclear [22mcommand can be used to do
             this if wanted, as is typically the case for "inset"
             plots.

             Any labels or arrows that have been defined will be drawn
             for each plot according to the current size and origin
             (unless their coordinates are defined in the [1mscreen [22msys-
             tem).  Just about everything else that can be [1mset [22mis
             applied to each plot, too.  If you want something to
             appear only once on the page, for instance a single time
             stamp, you'll need to put a [1mset time[22m/[1munset time [22mpair
             around one of the [1mplot[22m, [1msplot [22mor [1mreplot [22mcommands within
             the [1mset multiplot[22m/[1munset multiplot [22mblock.

             The multiplot title is separate from the individual plot
             titles, if any.  Space is reserved for it at the top of
             the page, spanning the full width of the canvas.

             The commands [1mset origin [22mand [1mset size [22mmust be used to cor-
             rectly position each plot if no layout is specified or if
             fine tuning is desired.  See [1mset origin [22mand [1mset size [22mfor
             details of their usage.

             Example:
                   set multiplot
                   set size 0.4,0.4










   GNUPLOT 4.1                                                      186


                   set origin 0.1,0.1
                   plot sin(x)
                   set size 0.2,0.2
                   set origin 0.5,0.5
                   plot cos(x)
                   unset multiplot

             This displays a plot of cos(x) stacked above a plot of
             sin(x).

             [1mset size [22mand [1mset origin [22mrefer to the entire plotting area
             used for each plot.  Please also see [1mset term size[22m.  If
             you want to have the axes themselves line up, you can
             guarantee that the margins are the same size with the [1mset[0m
             [1mmargin [22mcommands.  See [1mset margin [22mfor their use.  Note that
             the margin settings are absolute, in character units, so
             the appearance of the graph in the remaining space will
             depend on the screen size of the display device, e.g.,
             perhaps quite different on a video display and a printer.

             With the [1mlayout [22moption you can generate simple multiplots
             without having to give the [1mset size [22mand [1mset origin [22mcom-
             mands before each plot:  Those are generated automati-
             cally, but can be overridden at any time.  With [1mlayout [22mthe
             display will be divided by a grid with <rows> rows and
             <cols> columns.  This grid is filled rows first or columns
             first depending on whether the corresponding option is
             given in the multiplot command.  The stack of plots can
             grow [1mdownwards [22mor [1mupwards[22m.  Default is [1mrowsfirst [22mand [1mdown-[0m
             [1mwards[22m.

             Each plot can be scaled by [1mscale [22mand shifted with [1moffset[22m;
             if the y-values for scale or offset are omitted, the x-
             value will be used.  [1munset multiplot [22mwill turn off the
             automatic layout and restore the values of [1mset size [22mand
             [1mset origin [22mas they were before [1mset multiplot layout[22m.

             Example:
                   set size 1,1
                   set origin 0,0
                   set multiplot layout 3,2 columnsfirst scale 1.1,0.9
                   [ up to 6 plot commands here ]
                   unset multiplot

             The above example will produce 6 plots in 2 columns filled
             top to bottom, left to right.  Each plot will have a hori-
             zontal size of 1.1/2 and a vertical size of 0.9/3.

             See also multiplot demo (multiplt.dem)














   GNUPLOT 4.1                                                      187


             [1m84.42.  Mx2tics[0m


             Minor tic marks along the x2 (top) axis are controlled by
             [1mset mx2tics[22m.  Please see [1mset mxtics[22m.



             [1m84.43.  Mxtics[0m


             Minor tic marks along the x axis are controlled by [1mset[0m
             [1mmxtics[22m.  They can be turned off with [1munset mxtics[22m.  Simi-
             lar commands control minor tics along the other axes.

             Syntax:
                   set mxtics {<freq> | default}
                   unset mxtics
                   show mxtics

             The same syntax applies to [1mmytics[22m, [1mmztics[22m, [1mmx2tics[22m,
             [1mmy2tics [22mand [1mmcbtics[22m.

             <freq> is the number of sub-intervals (NOT the number of
             minor tics) between major tics (the default for a linear
             axis is either two or five depending on the major tics, so
             there are one or four minor tics between major tics).
             Selecting [1mdefault [22mwill return the number of minor ticks to
             its default value.

             If the axis is logarithmic, the number of sub-intervals
             will be set to a reasonable number by default (based upon
             the length of a decade).  This will be overridden if
             <freq> is given.  However the usual minor tics (2, 3, ...,
             8, 9 between 1 and 10, for example) are obtained by set-
             ting <freq> to 10, even though there are but nine sub-
             intervals.

             To set minor tics at arbitrary positions, use the
             ("<label>" <pos> <level>, ...) form of [1mset[0m
             [1m{x|x2|y|y2|z}tics [22mwith <label> empty and <level> set to 1.

             The [1mset m{x|x2|y|y2|z}tics [22mcommands work only when there
             are uniformly spaced major tics.  If all major tics were
             placed explicitly by [1mset {x|x2|y|y2|z}tics[22m, then minor tic
             commands are ignored.  Implicit major tics and explicit
             minor tics can be combined using [1mset {x|x2|y|y2|z}tics [22mand
             [1mset {x|x2|y|y2|z}tics add[22m.

             Examples:
                   set xtics 0, 5, 10
                   set xtics add (7.5)
                   set mxtics 5










   GNUPLOT 4.1                                                      188


             Major tics at 0,5,7.5,10, minor tics at 1,2,3,4,6,7,8,9
                   set logscale y
                   set ytics format ""
                   set ytics 1e-6, 10, 1
                   set ytics add ("1" 1, ".1" 0.1, ".01" 0.01, "10^-3"
             0.001, \
                                  "10^-4" 0.0001)
                   set mytics 10
             Major tics with special formatting, minor tics at log
             positions

             By default, minor tics are off for linear axes and on for
             logarithmic axes.  They inherit the settings for [1maxis|bor-[0m
             [1mder [22mand [1m{no}mirror [22mspecified for the major tics.  Please
             see [1mset xtics [22mfor information about these.



             [1m84.44.  My2tics[0m


             Minor tic marks along the y2 (right-hand) axis are con-
             trolled by [1mset my2tics[22m.  Please see [1mset mxtics[22m.



             [1m84.45.  Mytics[0m


             Minor tic marks along the y axis are controlled by [1mset[0m
             [1mmytics[22m.  Please see [1mset mxtics[22m.



             [1m84.46.  Mztics[0m


             Minor tic marks along the z axis are controlled by [1mset[0m
             [1mmztics[22m.  Please see [1mset mxtics[22m.



             [1m84.47.  Object[0m


             The [1mset object [22mcommand defines a single object which will
             appear in all subsequent 2D plots. You may define as many
             objects as you like. Currently the supported object types
             are [1mrectangle[22m, [1mcircle[22m, [1mellipse[22m, and [1mpolygon[22m.  Rectangles
             inherit a default set of style properties (fill, color,
             border) from those set by the command [1mset style rectangle[22m,
             but each object can also be given individual style proper-
             ties. Circles, ellipses, and polygons  inherit the fill










   GNUPLOT 4.1                                                      189


             style from [1mset style fill[22m.

             Syntax:
                 set object <index>
                     <object-type> <object-properties>
                     {front|back|behind} {fc|fillcolor <colorspec>} {fs
             <fillstyle>}
                     {default} {lw|linewidth <width>}

             <object-type> is either [1mrectangle[22m, [1mellipse[22m, [1mcircle[22m, or
             [1mpolygon[22m.  Each object type has its own set of characteris-
             tic properties.

             Setting [1mfront [22mwill draw the object in front of all plot
             elements, but behind any labels that are also marked
             [1mfront[22m. Setting [1mback [22mwill place the object behind all plot
             curves and labels. Setting [1mbehind [22mwill place the object
             behind everything including the axes and [1mback [22mrectangles,
             thus
                 set object rectangle from screen 0,0 to screen 1,1
             behind
             can be used to provide a colored background for the entire
             graph or page.

             The fill color of the object is taken from the <color-
             spec>. [1mfillcolor [22mmay be abbreviated [1mfc[22m.  The fill style is
             taken from <fillstyle>.  See [1mcolorspec [22mand [1mfillstyle[22m.  If
             the keyword [1mdefault [22mis given, these properties are inher-
             ited from the default settings at the time a plot is
             drawn. See [1mset style rectangle[22m.




                  [1m84.47.1.  Rectangle[0m


                  Syntax:
                      set object <index> rectangle
                          {from <position> {to|rto} <position> |
                           center <position> size <w>,<h> |
                           at <position> size <w>,<h>}

                  The position of the rectangle may be specified by
                  giving the position of two diagonal corners (bottom
                  left and top right) or by giving the position of the
                  center followed by the width and the height.  In
                  either case the positions may be given in axis,
                  graph, or screen coordinates. See [1mcoordinates[22m.  The
                  options [1mat [22mand [1mcenter [22mare synonyms.

                  Examples:
                      # Force the entire area enclosed by the axes to










   GNUPLOT 4.1                                                      190


                  have background color cyan
                      set object 1 rect from graph 0, graph 0 to graph
                  1, graph 1 back
                      set object 1 rect fc rgb "cyan" fillstyle solid
                  1.0

                      # Position a red square with lower left at 0,0
                  and upper right at 2,3
                      set object 2 rect from 0,0 to 2,3 fc lt 1

                      # Position an empty rectangle (no fill) with a
                  blue border
                      set object 3 rect from 0,0 to 2,3 fs empty border
                  rgb "blue"

                      # Return fill and color to the default style but
                  leave vertices unchanged
                      set object 2 rect default

                  Rectangle corners specified in screen coordinates may
                  extend beyond the edge of the current graph. Other-
                  wise the rectangle is clipped to fit in the graph.




                  [1m84.47.2.  Ellipse[0m


                  Syntax:
                      set object <index> ellipse {at|center} <position>
                  size <w>,<h>
                          {angle <orientation>} {units xy|xx|yy}
                          {<other-object-properties>}

                  The position of the ellipse is specified by giving
                  the center followed by the width and the height
                  (actually the major and minor axes). The keywords [1mat[0m
                  and [1mcenter [22mare synonyms.  The center position may be
                  given in axis, graph, or screen coordinates. See
                  [1mcoordinates[22m. The major and minor axis lengths must be
                  given in axis coordinates.  The orientation of the
                  ellipse is specified by the angle between the hori-
                  zontal axis and the major diameter of the ellipse.
                  If no angle is given, the default ellipse orientation
                  will be used instead (see [1mset style ellipse[22m).  The
                  [1munits [22mkeyword controls the scaling of the axes of the
                  ellipse. [1munits xy [22mmeans that the major axis is inter-
                  preted in terms of units along the x axis, while the
                  minor axis in that of the y axis. [1munits xx [22mmeans that
                  both axes of the ellipses are scaled in the units of
                  the x axis, while [1munits yy [22mmeans that both axes are
                  in units of the y axis.  The default is [1mxy [22mor










   GNUPLOT 4.1                                                      191


                  whatever [1mset style ellipse units [22mwas set to.

                  NB: If the x and y axis scales are not equal, (e.g.
                  [1munits xy [22mis in effect) then the major/minor axis
                  ratio will no longer be correct after rotation.

                  Note that [1mset object ellipse size <2r>,<2r> [22mdoes not
                  in general produce the same result as [1mset object cir-[0m
                  [1mcle <r>[22m.  The circle radius is always interpreted in
                  terms of units along the x axis, and will always pro-
                  duce a circle even if the x and y axis scales are
                  different and even if the aspect ratio of your plot
                  is not 1.  If [1munits [22mis set to [1mxy[22m, then 'set object
                  ellipse' interprets the first <2r> in terms of x axis
                  units and the second <2r> in terms of y axis units.
                  This will only produce a circle if the x and y axis
                  scales are identical and the plot aspect ratio is 1.
                  On the other hand, if [1munits [22mis set to [1mxx [22mor [1myy[22m, then
                  the diameters specified in the 'set object' command
                  will be interpreted in the same units, so the ellipse
                  will have the correct aspect ratio, and it will main-
                  tain its aspect ratio even if the plot is resized.




                  [1m84.47.3.  Circle[0m


                  Syntax:
                      set object <index> circle {at|center} <position>
                  size <radius>
                          {arc [<begin>:<end>]}
                          {<other-object-properties>}

                  The position of the circle is specified by giving the
                  position of the center center followed by the radius.
                  The keywords [1mat [22mand [1mcenter [22mare synonyms.  The posi-
                  tion and radius may be given in x-axis, graph, or
                  canvas coordinates. See [1mcoordinates[22m. In all cases the
                  radius is calculated relative to the horizontal scale
                  of the axis, graph, or canvas.  Any disparity between
                  the horizontal and vertical scaling will be corrected
                  for so that the result is always a circle.

                  By default a full circle is drawn. The optional qual-
                  ifier [1marc [22mspecifies a starting angle and ending
                  angle, in degrees, for one arc of the circle.  The
                  arc is always drawn counterclockwise.














   GNUPLOT 4.1                                                      192


                  [1m84.47.4.  Polygon[0m


                  Syntax:
                      set object <index> polygon
                          from <position> to <position> ... {to <posi-
                  tion>}
                  or
                          from <position> rto <position> ... {rto
                  <position>}

                  The position of the polygon may be specified by giv-
                  ing the position of a sequence of vertices. These may
                  be given in axis, graph, or screen coordinates.  If
                  relative coordinates are used (rto) then the coordi-
                  nate type must match that of the previous vertex.
                  See [1mcoordinates[22m.

                  Example:
                      set object 1 polygon from 0,0 to 1,1 to 2,0
                      set object 1 fc rgb "cyan" fillstyle solid 1.0
                  border lt -1




             [1m84.48.  Offsets[0m


             Offsets provide a mechanism to put an empty boundary
             around the data inside an autoscaled graph.  The offsets
             only affect the x1 and y1 axes, and only in 2D [1mplot [22mcom-
             mands.

             Syntax:
                   set offsets <left>, <right>, <top>, <bottom>
                   unset offsets
                   show offsets

             Each offset may be a constant or an expression.  Each
             defaults to 0.  By default, the left and right offsets are
             given in units of the first x axis, the top and bottom
             offsets in units of the first y axis.  Alternatively, you
             may specify the offsets as a fraction of the total axis
             range by using the keyword "graph".  A positive offset
             expands the axis range in the specified direction, e.g., a
             positive bottom offset makes ymin more negative.  Negative
             offsets, while permitted, can have unexpected interactions
             with autoscaling and clipping.  To prevent the auto-scal-
             ing from further adjusting your axis ranges, it is useful
             to also specify "set auto fix".

             Example:










   GNUPLOT 4.1                                                      193


                   set auto fix
                   set offsets graph 0.05, 0, 2, 2
                   plot sin(x)

             This graph of sin(x) will have a y range [-3:3] because
             the function will be autoscaled to [-1:1] and the vertical
             offsets are each two.  The x range will be [-11:10]
             because the default is [-10:10] and it has been expanded
             to the left by 0.05 of that total range.



             [1m84.49.  Origin[0m


             The [1mset origin [22mcommand is used to specify the origin of a
             plotting surface (i.e., the graph and its margins) on the
             screen.  The coordinates are given in the [1mscreen [22mcoordi-
             nate system (see [1mcoordinates [22mfor information about this
             system).

             Syntax:
                   set origin <x-origin>,<y-origin>



             [1m84.50.  Output[0m


             By default, screens are displayed to the standard output.
             The [1mset output [22mcommand redirects the display to the speci-
             fied file or device.

             Syntax:
                   set output {"<filename>"}
                   show output

             The filename must be enclosed in quotes.  If the filename
             is omitted, any output file opened by a previous invoca-
             tion of [1mset output [22mwill be closed and new output will be
             sent to STDOUT.  (If you give the command [1mset output "STD-[0m
             [1mOUT"[22m, your output may be sent to a file named "STDOUT"!
             ["May be", not "will be", because some terminals, like [1mx11[0m
             or [1mwxt[22m, ignore [1mset output[22m.])

             When both [1mset terminal [22mand [1mset output [22mare used together,
             it is safest to give [1mset terminal [22mfirst, because some ter-
             minals set a flag which is needed in some operating sys-
             tems.  This would be the case, for example, if the operat-
             ing system needs to know whether or not a file is to be
             formatted in order to open it properly.

             On machines with popen functions (Unix), output can be










   GNUPLOT 4.1                                                      194


             piped through a shell command if the first non-whitespace
             character of the filename is '|'.  For instance,

                   set output "|lpr -Plaser filename"
                   set output "|lp -dlaser filename"

             On MSDOS machines, [1mset output "PRN" [22mwill direct the output
             to the default printer.  On VMS, output can be sent
             directly to any spooled device.  It is also possible to
             send the output to DECnet transparent tasks, which allows
             some flexibility.



             [1m84.51.  Parametric[0m


             The [1mset parametric [22mcommand changes the meaning of [1mplot[0m
             ([1msplot[22m) from normal functions to parametric functions.
             The command [1munset parametric [22mrestores the plotting style
             to normal, single-valued expression plotting.

             Syntax:
                   set parametric
                   unset parametric
                   show parametric

             For 2D plotting, a parametric function is determined by a
             pair of parametric functions operating on a parameter.  An
             example of a 2D parametric function would be [1mplot[0m
             [1msin(t),cos(t)[22m, which draws a circle (if the aspect ratio
             is set correctly---see [1mset size[22m).  [1mgnuplot [22mwill display an
             error message if both functions are not provided for a
             parametric [1mplot[22m.

             For 3D plotting, the surface is described as x=f(u,v),
             y=g(u,v), z=h(u,v).  Therefore a triplet of functions is
             required.  An example of a 3D parametric function would be
             [1mcos(u)*cos(v),cos(u)*sin(v),sin(u)[22m, which draws a sphere.
             [1mgnuplot [22mwill display an error message if all three func-
             tions are not provided for a parametric [1msplot[22m.

             The total set of possible plots is a superset of the sim-
             ple f(x) style plots, since the two functions can describe
             the x and y values to be computed separately.  In fact,
             plots of the type t,f(t) are equivalent to those produced
             with f(x) because the x values are computed using the
             identity function.  Similarly, 3D plots of the type
             u,v,f(u,v) are equivalent to f(x,y).

             Note that the order the parametric functions are specified
             is xfunction, yfunction (and zfunction) and that each
             operates over the common parametric domain.










   GNUPLOT 4.1                                                      195


             Also, the [1mset parametric [22mfunction implies a new range of
             values.  Whereas the normal f(x) and f(x,y) style plotting
             assume an xrange and yrange (and zrange), the parametric
             mode additionally specifies a trange, urange, and vrange.
             These ranges may be set directly with [1mset trange[22m, [1mset[0m
             [1murange[22m, and [1mset vrange[22m, or by specifying the range on the
             [1mplot [22mor [1msplot [22mcommands.  Currently the default range for
             these parametric variables is [-5:5].  Setting the ranges
             to something more meaningful is expected.



             [1m84.52.  Plot[0m


             The [1mshow plot [22mcommand shows the current plotting command
             as it results from the last [1mplot [22mand/or [1msplot [22mand possible
             subsequent [1mreplot [22mcommands.

             In addition, the [1mshow plot add2history [22mcommand adds this
             current plot command into the [1mhistory[22m. It is useful if you
             have used [1mreplot [22mto add more curves to the current plot
             and you want to edit the whole command now.



             [1m84.53.  Pm3d[0m


             pm3d is an [1msplot [22mstyle for drawing palette-mapped 3d and
             4d data as color/gray maps and surfaces.  It uses an algo-
             rithm that allows plotting gridded as well as non-gridded
             data without preprocessing, even when the data scans do
             not have the same number of points.

             Syntax (the options can be given in any order):
                   set pm3d {
                              { at <position> }
                              { interpolate <steps/points in scan,
             between scans> }
                              { scansautomatic | scansforward | scans-
             backward | depthorder }
                              { flush { begin | center | end } }
                              { ftriangles | noftriangles }
                              { clip1in | clip4in }
                              { corners2color {
             mean|geomean|median|min|max|c1|c2|c3|c4 } }
                              { hidden3d {<linestyle>} | nohidden3d }
                              { implicit | explicit }
                              { map }
                            }
                   show pm3d
                   unset pm3d










   GNUPLOT 4.1                                                      196


             A pm3d color surface is drawn if the splot command speci-
             fies [1mwith pm3d[22m, if the data or function [1mstyle [22mis set to
             pm3d globally, or if the pm3d mode is [1mset pm3d implicit[22m.
             In the latter two cases, the pm3d surface is draw in addi-
             tion to the mesh produced by the style specified in the
             plot command. E.g.
                   splot 'fred.dat' with lines, 'lola.dat' with lines
             would draw both a mesh of lines and a pm3d surface for
             each data set.  If the option [1mexplicit [22mis on (or [1mimplicit[0m
             is off) only plots specified by the [1mwith pm3d [22mattribute
             are plotted with a pm3d surface, e.g.:
                   splot 'fred.dat' with lines, 'lola.dat' with pm3d
             would plot 'fred.dat' with lines (only) and 'lola.dat'
             with a pm3d surface.

             On gnuplot start-up, the mode is [1mexplicit[22m. For historical
             and compatibility reasons, the commands [1mset pm3d; [22m(i.e. no
             options) and [1mset pm3d at X ...  [22m(i.e.  [1mat [22mis the first
             option) change the mode to [1mimplicit[22m.  The command [1mset[0m
             [1mpm3d; [22msets other options to their default state.

             If you set the default data or function style to [1mpm3d[22m,
             e.g.:
                   set style data pm3d
             then the options [1mimplicit [22mand [1mexplicit [22mhave no effect.

             Note that when plotting several plots, they are plotted in
             the order given on the command line. This can be of inter-
             est especially for filled surfaces which can overwrite and
             therefore hide part of earlier plots.

             The pm3d coloring can be drawn at any or all of three dif-
             ferent positions, [1mtop[22m, [1mbottom[22m, or [1msurface[22m. See [1mpm3d posi-[0m
             [1mtion[22m.  The following command draws three color surfaces at
             different altitudes:
                   set border 4095
                   set pm3d at s
                   splot 10*x with pm3d at b, x*x-y*y, x*x+y*y with
             pm3d at t

             See also help for [1mset palette[22m, [1mset cbrange[22m, [1mset colorbox[22m,
             and definitely the demo file [1mdemo/pm3d.dem[22m.




                  [1m84.53.1.  Algorithm[0m



                  Let us first describe how a map/surface is drawn.
                  The input data come from an evaluated function or
                  from an [1msplot data file[22m.  Each surface consists of a










   GNUPLOT 4.1                                                      197


                  sequence of separate scans (isolines).  The pm3d
                  algorithm fills the region between two neighbouring
                  points in one scan with another two points in the
                  next scan by a gray (or color) according to z-values
                  (or according to an additional 'color' column, see
                  help for [1musing[22m) of these 4 corners; by default the 4
                  corner values are averaged, but this can be changed
                  by the option [1mcorners2color[22m.  In order to get a rea-
                  sonable surface, the neighbouring scans should not
                  cross and the number of points in the neighbouring
                  scans should not differ too much; of course, the best
                  plot is with scans having same number of points.
                  There are no other requirements (e.g. the data need
                  not be gridded).  Another advantage is that the pm3d
                  algorithm does not draw anything outside of the input
                  (measured or calculated) region.

                  Surface coloring works with the following input data:

                  1. splot of function or of data file with one or
                  three data columns: The gray/color scale is obtained
                  by mapping the averaged (or [1mcorners2color[22m) z-coordi-
                  nate of the four corners of the above-specified quad-
                  rangle into the range [min_color_z,max_color_z] of
                  [1mzrange [22mor [1mcbrange [22mproviding a gray value in the range
                  [0:1].  This value can be used directly as the gray
                  for gray maps.  The normalized gray value can be fur-
                  ther mapped into a color---see [1mset palette [22mfor the
                  complete description.

                  2. splot of data file with two or four data columns:
                  The gray/color value is obtained by using the last-
                  column coordinate instead of the z-value, thus allow-
                  ing the color and the z-coordinate be mutually inde-
                  pendent.  This can be used for 4d data drawing.

                  Other notes:

                  1. The term 'scan' referenced above is used more
                  among physicists than the term 'iso_curve' referenced
                  in gnuplot documentation and sources.  You measure
                  maps recorded one scan after another scan, that's
                  why.

                  2. The 'gray' or 'color' scale is a linear mapping of
                  a continuous variable onto a smoothly varying palette
                  of colors. The mapping is shown in a rectangle next
                  to the main plot. This documentation refers to this
                  as a "colorbox", and refers to the indexing variable
                  as lying on the colorbox axis.  See [1mset colorbox[22m, [1mset[0m
                  [1mcbrange[22m.

                  3. To use pm3d coloring to generate a two-dimensional










   GNUPLOT 4.1                                                      198


                  plot rather than a 3D surface, use [1mset view map [22mor
                  [1mset pm3d map[22m.



                  [1m84.53.2.  Position[0m


                  Color surface can be drawn at the base or top (then
                  it is a gray/color planar map) or at z-coordinates of
                  surface points (gray/color surface).  This is defined
                  by the [1mat [22moption with a string of up to 6 combina-
                  tions of [1mb[22m, [1mt [22mand [1ms[22m. For instance, [1mat b [22mplots at bot-
                  tom only, [1mat st [22mplots firstly surface and then top
                  map, while [1mat bstbst [22mwill never by seriously used.

                  Colored quadrangles are plotted one after another.
                  When plotting surfaces ([1mat s[22m), the later quadrangles
                  overlap (overdraw) the previous ones.  (Gnuplot is
                  not virtual reality tool to calculate intersections
                  of filled polygon meshes.)  You may try to switch
                  between [1mscansforward [22mand [1mscansbackward [22mto force the
                  first scan of the data to be plotted first or last.
                  The default is [1mscansautomatic [22mwhere gnuplot makes a
                  guess about scans order.  On the other hand, the
                  [1mdepthorder [22moption completely reorders the quadran-
                  gles. The rendering is performed after a depth sort-
                  ing, which allows to visualize even complicated sur-
                  faces; see [1mpm3d depthorder [22mfor more details.



                  [1m84.53.3.  Scanorder[0m


                  By default the quadrangles making up a pm3d solid
                  surface are rendered in the order they are encoun-
                  tered along the surface grid points.  This order may
                  be controlled by the options [1mscansautomatic[22m|[1mscansfor-[0m
                  [1mward[22m|[1mscansbackward[22m.  These scan options are not in
                  general compatible with hidden-surface removal.

                  If two successive scans do not have same number of
                  points, then it has to be decided whether to start
                  taking points for quadrangles from the beginning of
                  both scans ([1mflush begin[22m), from their ends ([1mflush end[22m)
                  or to center them ([1mflush center[22m).  Note, that [1mflush[0m
                  [1m(center|end) [22mare incompatible with [1mscansautomatic[22m: if
                  you specify [1mflush center [22mor [1mflush end [22mand [1mscansauto-[0m
                  [1mmatic [22mis set, it is silently switched to [1mscansfor-[0m
                  [1mward[22m.

                  If two subsequent scans do not have the same number










   GNUPLOT 4.1                                                      199


                  of points, the option [1mftriangles [22mspecifies whether
                  color triangles are drawn at the scan tail(s) where
                  there are not enough points in either of the scan.
                  This can be used to draw a smooth map boundary.

                  Gnuplot does not do true hidden surface removal for
                  solid surfaces, but often it is sufficient to render
                  the component quadrangles in order from furthest to
                  closest.  This mode may be selected using the options
                        set pm3d depthorder hidden3d
                  The [1mdepthorder [22moption orders the solid quadrangles;
                  the [1mhidden3d [22moption similarly orders the bounding
                  lines (if drawn).  Note that the global option [1mset[0m
                  [1mhidden3d [22mdoes not affect pm3d surfaces.




                  [1m84.53.4.  Clipping[0m


                  Clipping with respect to x, y coordinates of quadran-
                  gles can be done in two ways.  [1mclip1in[22m: all 4 points
                  of each quadrangle must be defined and at least 1
                  point of the quadrangle must lie in the x and y
                  ranges.  [1mclip4in[22m: all 4 points of each quadrangle
                  must lie in the x and y ranges.




                  [1m84.53.5.  Color_assignment[0m


                  [1m3 columns of data (x,y,z)[22m:

                  The coloring setup as well as the color box drawing
                  are determined by [1mset palette[22m.  There can be only one
                  palette for the current plot.  Drawing of several
                  surfaces with different palettes can be achieved by
                  [1mmultiplot [22mwith fixed [1morigin [22mand [1msize[22m; don't forget to
                  use [1mset palette maxcolors [22mwhen your terminal is run-
                  ning out of available colors.

                  There is a single gray/color value associated to each
                  drawn pm3d quadrangle (no smooth color change among
                  vertices).  The value is calculated from z-coordi-
                  nates from the surrounding corners according to [1mcor-[0m
                  [1mners2color <option>[22m.  The options 'mean' (default),
                  'geomean' and 'median' produce various kinds of sur-
                  face color smoothing, while options 'min' and 'max'
                  choose minimal or maximal value, respectively. This
                  may not be desired for pixel images or for maps with










   GNUPLOT 4.1                                                      200


                  sharp and intense peaks, in which case the options
                  'c1', 'c2', 'c3' or 'c4' can be used instead to
                  assign the quadrangle color based on the z-coordinate
                  of only one corner.  Some experimentation may be
                  needed to determine which corner corresponds to 'c1',
                  as the orientation depends on the drawing direction.
                  Because the pm3d algorithm does not extend the col-
                  ored surface outside the range of the input data
                  points, the 'c<j>' coloring options will result in
                  pixels along two edges of the grid not contributing
                  to the color of any quadrangle.  For example, apply-
                  ing the pm3d algorithm to the 4x4 grid of data points
                  in script [1mdemo/pm3d.dem [22m(please have a look) produces
                  only (4-1)x(4-1)=9 colored rectangles.

                  [1m4 columns of data (x,y,z,color)[22m:

                  If a fourth column of data is provided, it is nor-
                  mally interpreted as a separate palette-mapped gray
                  value. The coloring of individual quadrangles works
                  as above, except that the color value is distinct
                  from the z value.  As a separate coloring option, the
                  fourth data column may provide instead an RGB color.
                  See [1mrgbcolor variable[22m. In this case the plotting com-
                  mand must be

                        splot ... using 1:2:3:4 with pm3d lc rgb vari-
                  able

                  Another drawing algorithm, which would draw quadran-
                  gles around a given node by taking corners from aver-
                  aged (x,y)-coordinates of its surrounding 4 nodes
                  while using node's color, could be implemented in the
                  future. This is already done for drawing images (2D
                  grids) via [1mimage [22mand [1mrgbimage [22mstyles.

                  Notice that ranges of z-values and color-values for
                  surfaces are adjustable independently by [1mset zrange[22m,
                  [1mset cbrange[22m, as well as [1mset log [22mfor z or cb.  Maps
                  can be adjusted by the cb-axis only; see also [1mset[0m
                  [1mview map [22mand [1mset colorbox[22m.



                  [1m84.53.6.  Hidden3d[0m


                  The option [1mset pm3d hidden3d [22mdraws the bounding lines
                  of each quadrangle at the same time that the quadran-
                  gle itself is drawn. Normally it is used in conjunc-
                  tion with the [1mdepthorder [22moption to achieve an approx-
                  imation to true hidden line removal.  This is far
                  more efficient than using the command [1mset hidden3d[22m.










   GNUPLOT 4.1                                                      201


                  The command takes an optional linestyle controlling
                  the appearance of the bounding lines.  If the
                  linestyle parameter is negative, or omitted, then the
                  line properties given in the plot command are used.
                  Example of recommended usage:

                        set pm3d at s hidden3d depthorder
                        unset hidden3d
                        unset surf
                        splot x*x+y*y linecolor rgb "black" linewidth
                  0.5




                  [1m84.53.7.  Interpolate[0m


                  The option [1minterpolate m,n [22mwill interpolate grid
                  points into a finer mesh, and color each quadrangle
                  appropriately.  For data files, this will smoothen
                  the color surface, and enhance spikes in a color sur-
                  face. For functions, interpolation makes little
                  sense, except to trade off precision for memory.  It
                  would usually make more sense to use [1msamples [22mand
                  [1misosamples [22mwhen working with functions. For positive
                  m and n, each quadrangle or triangle is interpolated
                  m-times and n-times in the respective direction.  For
                  negative m and n, the interpolation frequency is cho-
                  sen so that there will be at least |m| and |n| points
                  drawn; you can consider this as a special gridding
                  function.  Zeros, i.e. [1minterpolate 0,0[22m, will automat-
                  ically choose an optimal number of interpolated sur-
                  face points.



                  [1m84.53.8.  Deprecated_options[0m


                  There used to be an option {transparent|solid} to
                  this command.  Now you get the same effect from [1mset[0m
                  [1mgrid {front|layerdefault}[22m, respectively.

                  The command [1mset pm3d map [22mis equivalent to [1mset pm3d at[0m
                  [1mb[22m; [1mset view map[22m; [1mset style data pm3d[22m; [1mset style func[0m
                  [1mpm3d[22m;.  It is used for backwards compatibility, when
                  [1mset view map [22mwas not available.  Take care that you
                  properly use [1mzrange [22mand [1mcbrange [22mfor input data point
                  filtering and color range scaling, respectively; and
                  also [1mset (no)surface [22mseems to have a (side?) effect.












   GNUPLOT 4.1                                                      202


             [1m84.54.  Palette[0m


             Palette is a color storage for use by [1mpm3d[22m, filled color
             contours or polygons, color histograms, color gradient
             background, and whatever it is or it will be imple-
             mented...  Here it stands for a palette of smooth "contin-
             uous" colors or grays, but let's call it just a palette.

             Color palettes require terminal entries for filled color
             polygons and palettes of smooth colors, are currently
             available for terminals listed in help for [1mset pm3d[22m. The
             range of color values are adjustable independently by [1mset[0m
             [1mcbrange [22mand [1mset log cb[22m. The whole color palette is visual-
             ized in the [1mcolorbox[22m.

             Syntax:
                   set palette
                   set palette {
                              { gray | color }
                              { gamma <gamma> }
                              {   rgbformulae <r>,<g>,<b>
                                | defined { ( <gray1> <color1> {,
             <grayN> <colorN>}... ) }
                                | file '<filename>' {datafile-modi-
             fiers}
                                | functions <R>,<G>,<B>
                              }
                              { cubehelix {start <val>} {cycles <val>}
             {saturation <val>} }
                              { model { RGB | HSV | CMY | YIQ | XYZ } }
                              { positive | negative }
                              { nops_allcF | ps_allcF }
                              { maxcolors <maxcolors> }
                            }
                   show palette
                   show palette palette <n> {{float | int}}
                   show palette gradient
                   show palette fit2rgbformulae
                   show palette rgbformulae
                   show colornames

             [1mset palette [22m(i.e. without options) sets up the default
             values.  Otherwise, the options can be given in any order.
             [1mshow palette [22mshows the current palette properties.

             [1mshow palette gradient [22mdisplays the gradient defining the
             palette (if appropriate).  [1mshow palette rgbformulae [22mprints
             the available fixed gray --> color transformation formu-
             lae.  [1mshow colornames [22mprints the known color names.

             [1mshow palette palette <n> [22mprints to the screen or to the
             file given by [1mset print [22ma table of RGB triplets calculated










   GNUPLOT 4.1                                                      203


             for the current palette settings and a palette having <n>
             discrete colors.  The default wide table can be limited to
             3 columns of r,g,b float values [0..1] or integer values
             [0..255] by options float or int, respectively.  This way,
             the current gnuplot color palette can be loaded into other
             imaging applications, for example Octave.  Additionally to
             this textual list of RGB table, you can use the [1mtest[0m
             [1mpalette [22mcommand to plot the R,G,B profiles for the current
             palette.

             The following options determine the coloring properties.

             Figure using this palette can be [1mgray [22mor [1mcolor[22m.  For
             instance, in [1mpm3d [22mcolor surfaces the gray of each small
             spot is obtained by mapping the averaged z-coordinate of
             the 4 corners of surface quadrangles into the range
             [min_z,max_z] providing range of grays [0:1]. This value
             can be used directly as the gray for gray maps. The color
             map requires a transformation gray --> (R,G,B), i.e. a
             mapping [0:1] --> ([0:1],[0:1],[0:1]).

             Basically two different types of mappings can be used:
             Analytic formulae to convert gray to color, or discrete
             mapping tables which are interpolated.  [1mpalette rgbformu-[0m
             [1mlae [22mand [1mpalette functions [22muse analytic formulae whereas
             [1mpalette defined [22mand [1mpalette file [22muse interpolated tables.
             [1mpalette rgbformulae [22mreduces the size of postscript output
             to a minimum.

             The command [1mshow palette fit2rgbformulae [22mfinds the best
             matching [1mset palette rgbformulae [22mfor the current [1mset[0m
             [1mpalette[22m. Naturally, it makes sense to use it for non-rgb-
             formulae palettes. This command can be found useful mainly
             for external programs using the same rgbformulae defini-
             tion of palettes as gnuplot, like zimg (
                       http://zimg.sourceforge.net
             ).

             [1mset palette gray [22mswitches to a gray only palette. [1mset[0m
             [1mpalette rgbformulae[22m, [1mset palette defined[22m, [1mset palette file[0m
             and [1mset palette functions [22mswitch to a color mapping. [1mset[0m
             [1mpalette color [22mis an easy way to switch back from the gray
             palette to the last color mapping.

             Automatic gamma correction via [1mset palette gamma <gamma>[0m
             can be done for gray maps ([1mset palette gray[22m) and for the
             [1mcubehelix [22mcolor palette schemes.  Gamma = 1 produces a
             linear ramp of intensity. See [1mtest palette[22m.

             Many terminals support only discrete number of colors
             (e.g. 256 colors in gif).  After the default gnuplot line-
             type colors are allocated, the rest of the available col-
             ors are by default reserved for pm3d.  Thus a multiplot










   GNUPLOT 4.1                                                      204


             using multiple palettes could fail because the first
             palette has used all the available color positions.  You
             can mitigate this limitation by using [1mset palette maxcol-[0m
             [1mors <N> [22mwith a reasonably small value of N.  This option
             causes N discrete colors to be selected from a continuous
             palette sampled at equally spaced intervals.  If you want
             unequal spacing of N discrete colors, use [1mset palette[0m
             [1mdefined [22minstead of a single continuous palette.

             RGB color space might not be the most useful color space
             to work in.  For that reason you may change the color
             space with [1mmodel [22mto one of [1mRGB[22m, [1mHSV[22m, [1mCMY[22m, [1mYIQ [22mand [1mXYZ[22m.
             Using color names for [1mset palette defined [22mtables and a
             color space other than RGB will result in funny colors.
             All explanation have been written for RGB color space, so
             please note, that [1mR [22mcan be [1mH[22m, [1mC[22m, [1mY[22m, or [1mX[22m, depending on the
             actual color space ([1mG [22mand [1mB [22maccordingly).

             All values for all color spaces are limited to [0,1].

             RGB stands for Red, Green and Blue;  CMY stands for Cyan,
             Magenta and Yellow; HSV stands for Hue, Saturation, and
             Value;  YIQ is the color model used by the U.S. Commercial
             Color Television Broadcasting, it is basically an RGB
             recoding with downward compatibility for black and white
             television; XYZ are the three primary colors of the color
             model defined by the 'Commission Internationale de
             l'Eclairage' (CIE).  For more information on color models
             see:
                       http://en.wikipedia.org/wiki/Color_space





                  [1m84.54.1.  Rgbformulae[0m


                  For [1mrgbformulae [22mthree suitable mapping functions have
                  to be chosen.  This is done via [1mrgbformulae[0m
                  [1m<r>,<g>,<b>[22m.  The available mapping functions are
                  listed by [1mshow palette rgbformulae[22m.  Default is
                  [1m7,5,15[22m, some other examples are [1m3,11,6[22m, [1m21,23,3 [22mor
                  [1m3,23,21[22m.  Negative numbers, like [1m3,-11,-6[22m, mean
                  inverted color (i.e.  1-gray passed into the formula,
                  see also [1mpositive [22mand [1mnegative [22moptions below).

                  Some nice schemes in RGB color space
                     7,5,15   ... traditional pm3d (black-blue-red-yel-
                  low)
                     3,11,6   ... green-red-violet
                     23,28,3  ... ocean (green-blue-white); try also
                  all other permutations










   GNUPLOT 4.1                                                      205


                     21,22,23 ... hot (black-red-yellow-white)
                     30,31,32 ... color printable on gray (black-blue-
                  violet-yellow-white)
                     33,13,10 ... rainbow (blue-green-yellow-red)
                     34,35,36 ... AFM hot (black-red-yellow-white)

                  A full color palette in HSV color space
                     3,2,2    ... red-yellow-green-cyan-blue-magenta-
                  red

                  Please note that even if called [1mrgbformulae [22mthe for-
                  mulas might actually determine the <H>,<S>,<V> or
                  <X>,<Y>,<Z> or ... color components as usual.

                  Use [1mpositive [22mand [1mnegative [22mto invert the figure col-
                  ors.

                  Note that it is possible to find a set of the best
                  matching rgbformulae for any other color scheme by
                  the command
                     show palette fit2rgbformulae



                  [1m84.54.2.  Defined[0m


                  Gray-to-rgb mapping can be manually set by use of
                  [1mpalette defined[22m: A color gradient is defined and used
                  to give the rgb values.  Such a gradient is a piece-
                  wise linear mapping from gray values in [0,1] to the
                  RGB space [0,1]x[0,1]x[0,1].  You must specify the
                  gray values and the corresponding RGB values between
                  which linear interpolation will be done.

                  Syntax:
                        set palette  defined { ( <gray1> <color1> {,
                  <grayN> <colorN>}... ) }

                  <grayX> are gray values which are mapped to [0,1] and
                  <colorX> are the corresponding rgb colors.  The color
                  can be specified in three different ways:

                       <color> :=  { <r> <g> <b> | '<color-name>' |
                  '#rrggbb' }

                  Either by three numbers (each in [0,1]) for red,
                  green and blue, separated by whitespace, or the name
                  of the color in quotes or X style color specifiers
                  also in quotes.  You may freely mix the three types
                  in a gradient definition, but the named color "red"
                  will be something strange if RGB is not selected as
                  color space.  Use [1mshow colornames [22mfor a list of known










   GNUPLOT 4.1                                                      206


                  color names.

                  Please note, that even if written as <r>, this might
                  actually be the <H> component in HSV color space or
                  <X> in CIE-XYZ space, or ...  depending on the
                  selected color model.

                  The <gray> values have to form an ascending sequence
                  of real numbers; the sequence will be automatically
                  rescaled to [0,1].

                  [1mset palette defined [22m(without a gradient definition in
                  braces) switches to RGB color space and uses a preset
                  full-spectrum color gradient.  Use [1mshow palette gra-[0m
                  [1mdient [22mto display the gradient.

                  Examples:

                  To produce a gray palette (useless but instructive)
                  use:
                        set palette model RGB
                        set palette defined ( 0 "black", 1 "white" )

                  To produce a blue yellow red palette use (all equiva-
                  lent):
                        set palette defined ( 0 "blue", 1 "yellow", 2
                  "red" )
                        set palette defined ( 0 0 0 1, 1 1 1 0, 2 1 0 0
                  )
                        set palette defined ( 0 "#0000ff", 1 "#ffff00",
                  2 "#ff0000" )

                  To produce some rainbow-like palette use:
                        set palette defined ( 0 "blue", 3 "green", 6
                  "yellow", 10 "red" )

                  Full color spectrum within HSV color space:
                        set palette model HSV
                        set palette defined ( 0 0 1 1, 1 1 1 1 )
                        set palette defined ( 0 0 1 0, 1 0 1 1, 6
                  0.8333 1 1, 7 0.8333 0 1)

                  Approximate the default palette used by MATLAB:
                        set pal defined (1 '#00008f', 8 '#0000ff', 24
                  '#00ffff', \
                                         40 '#ffff00', 56 '#ff0000', 64
                  '#800000')

                  To produce a palette with only a few, equally-spaced
                  colors:
                        set palette model RGB maxcolors 4
                        set palette defined ( 0 "yellow", 1 "red" )











   GNUPLOT 4.1                                                      207


                  'Traffic light' palette (non-smooth color jumps at
                  gray = 1/3 and 2/3).
                        set palette model RGB
                        set palette defined (0 "dark-green", 1 "green",
                  \
                                             1 "yellow",     2 "dark-
                  yellow", \
                                             2 "red",        3 "dark-
                  red" )




                  [1m84.54.3.  Functions[0m


                  Use [1mset palette functions <Rexpr>, <Gexpr>, <Bexpr>[0m
                  to define three formulae for the R(gray), G(gray) and
                  B(gray) mapping.  The three formulae may depend on
                  the variable [1mgray [22mwhich will take values in [0,1] and
                  should also produce values in [0,1].  Please note
                  that <Rexpr> might be a formula for the H-value if
                  HSV color space has been chosen (same for all other
                  formulae and color spaces).

                  Examples:

                  To produce a full color palette use:
                        set palette model HSV functions gray, 1, 1

                  A nice black to gold palette:
                        set palette model XYZ functions gray**0.35,
                  gray**0.5, gray**0.8

                  A gamma-corrected black and white palette
                        gamma = 2.2
                        color(gray) = gray**(1./gamma)
                        set palette model RGB functions color(gray),
                  color(gray), color(gray)




                  [1m84.54.4.  Cubehelix[0m


                  The "cubehelix" option defines a family of palettes
                  in which color (hue) varies along the standard color
                  wheel while at the same time the net intensity
                  increases monotonically as the gray value goes from 0
                  to 1.
                        D A Green (2011) http://arxiv.org/abs/1108.5083
                  [1mstart [22mdefines the starting point along the color










   GNUPLOT 4.1                                                      208


                  wheel in radians.  [1mcycles [22mdefines how many color
                  wheel cycles span the palette range.  Larger values
                  of [1msaturation [22mproduce more saturated color; satura-
                  tion > 1 may lead to clipping of the individual RGB
                  components and to intensity becoming non-monotonic.
                  The palette is also affected by [1mset palette gamma[22m.
                  The default values are
                        set palette cubehelix start 0.5 cycles -1.5
                  saturation 1
                        set palette gamma 1.5




                  [1m84.54.5.  File[0m


                  [1mset palette file [22mis basically a [1mset palette defined[0m
                  [1m(<gradient>) [22mwhere <gradient> is read from a
                  datafile.  Either 4 columns (gray,R,G,B) or just
                  three columns (R,G,B) have to be selected via the
                  [1musing [22mdata file modifier.  In the three column case,
                  the line number will be used as gray.  The gray range
                  is automatically rescaled to [0,1].  The file is read
                  as a normal data file, so all datafile modifiers can
                  be used.  Please note, that [1mR [22mmight actually be e.g.
                  [1mH [22mif HSV color space is selected.

                  As usual <filename> may be [1m'-' [22mwhich means that the
                  data follow the command inline and are terminated by
                  a single [1me [22mon a line of its own.

                  Use [1mshow palette gradient [22mto display the gradient.

                  Examples:

                  Read in a palette of RGB triples each in range
                  [0,255]:
                        set palette file 'some-palette' using
                  ($1/255):($2/255):($3/255)

                  Equidistant rainbow (blue-green-yellow-red) palette:
                        set palette model RGB file "-"
                        0 0 1
                        0 1 0
                        1 1 0
                        1 0 0
                        e

                  Binary palette files are supported as well, see
                  [1mbinary general[22m. Example: put 64 triplets of R,G,B
                  doubles into file palette.bin and load it by
                        set palette file "palette.bin" binary record=64










   GNUPLOT 4.1                                                      209


                  using 1:2:3





                  [1m84.54.6.  Gamma correction[0m


                  For gray mappings gamma correction can be turned on
                  by [1mset palette gamma <gamma>[22m.  <gamma> defaults to
                  1.5 which is quite suitable for most terminals.

                  The gamma correction is applied to the cubehelix
                  color palette family, but not to other palette color-
                  ing schemes. However, you may easily implement gamma
                  correction for explicit color functions.

                  Example:
                        set palette model RGB
                        set palette functions gray**0.64, gray**0.67,
                  gray**0.70

                  To use gamma correction with interpolated gradients
                  specify intermediate gray values with appropriate
                  colors.  Instead of

                        set palette defined ( 0 0 0 0, 1 1 1 1 )

                  use e.g.

                        set palette defined ( 0 0 0 0, 0.5 .73 .73 .73,
                  1 1 1 1 )

                  or even more intermediate points until the linear
                  interpolation fits the "gamma corrected" interpola-
                  tion well enough.




                  [1m84.54.7.  Postscript[0m


                  In order to reduce the size of postscript files, the
                  gray value and not all three calculated r,g,b values
                  are written to the file.  Therefore the analytical
                  formulae are coded directly in the postscript lan-
                  guage as a header just before the pm3d drawing, see
                  /g and /cF definitions.  Usually, it makes sense to
                  write therein definitions of only the 3 formulae
                  used.  But for multiplot or any other reason you may
                  want to manually edit the transformations directly in










   GNUPLOT 4.1                                                      210


                  the postscript file.  This is the default option
                  [1mnops_allcF[22m.  Using the option [1mps_allcF [22mwrites post-
                  script definitions of all formulae.  This you may
                  find interesting if you want to edit the postscript
                  file in order to have different palettes for differ-
                  ent surfaces in one graph.  Well, you can achieve
                  this functionality by [1mmultiplot [22mwith fixed [1morigin [22mand
                  [1msize[22m.

                  If pm3d map has been plotted from gridded or almost
                  regular data with an output to a postscript file,
                  then it is possible to reduce the size of this post-
                  script file up to at about 50% by the enclosed awk
                  script [1mpm3dCompress.awk[22m.  This you may find  inter-
                  esting if you intend to keep the file for including
                  it into your publication or before downloading a very
                  large file into a slow printer. Usage:
                      awk -f pm3dCompress.awk thefile.ps >smaller-
                  file.ps

                  If pm3d map has been plotted from rectangular gridded
                  data with an output to a postscript file, then it is
                  possible to reduce the file size even more by the
                  enclosed awk script [1mpm3dConvertToImage.awk[22m.  Usage:
                      awk -f pm3dConvertToImage.awk <thefile.ps >small-
                  erfile.ps

                  You may manually change the postscript output from
                  gray to color and vice versa and change the defini-
                  tion of <maxcolors>.



             [1m84.55.  Pointintervalbox[0m


             The [1mpointinterval [22mproperty of line types is used in plot
             style [1mlinespoints[22m.  A negative value of pointinterval,
             e.g. -N, means that point symbols are drawn only for every
             Nth point, and that a box (actually circle) behind each
             point symbol is blanked out by filling with the background
             color.  The command [1mset pointintervalbox [22mcontrols the
             radius of this blanked-out region.  It is a multiplier for
             the default radius, which is equal to the point size.



             [1m84.56.  Pointsize[0m


             The [1mset pointsize [22mcommand scales the size of the points
             used in plots.











   GNUPLOT 4.1                                                      211


             Syntax:
                   set pointsize <multiplier>
                   show pointsize

             The default is a multiplier of 1.0.  Larger pointsizes may
             be useful to make points more visible in bitmapped graph-
             ics.

             The pointsize of a single plot may be changed on the [1mplot[0m
             command.  See [1mplot with [22mfor details.

             Please note that the pointsize setting is not supported by
             all terminal types.



             [1m84.57.  Polar[0m


             The [1mset polar [22mcommand changes the meaning of the plot from
             rectangular coordinates to polar coordinates.

             Syntax:
                   set polar
                   unset polar
                   show polar

             In polar coordinates, the dummy variable (t) is an angle.
             The default range of t is [0:2*pi], or, if degree units
             have been selected, to [0:360] (see [1mset angles[22m).

             The command [1munset polar [22mchanges the meaning of the plot
             back to the default rectangular coordinate system.

             The [1mset polar [22mcommand is not supported for [1msplot[22ms.  See
             the [1mset mapping [22mcommand for similar functionality for
             [1msplot[22ms.

             While in polar coordinates the meaning of an expression in
             t is really r = f(t), where t is an angle of rotation.
             The trange controls the domain (the angle) of the func-
             tion. The r, x and y ranges control the extent of the
             graph in the x and y directions.  Each of these ranges, as
             well as the rrange, may be autoscaled or set explicitly.
             For details, see [1mset rrange [22mand [1mset xrange[22m.

             Example:
                   set polar
                   plot t*sin(t)
                   set trange [-2*pi:2*pi]
                   set rrange [0:3]
                   plot t*sin(t)











   GNUPLOT 4.1                                                      212


             The first [1mplot [22muses the default polar angular domain of 0
             to 2*pi.  The radius and the size of the graph are scaled
             automatically.  The second [1mplot [22mexpands the domain, and
             restricts the size of the graph to the area within 3 units
             of the origin.  This has the effect of limiting x and y to
             [-3:3].

             You may want to [1mset size square [22mto have [1mgnuplot [22mtry to
             make the aspect ratio equal to unity, so that circles look
             circular.  See also polar demos (polar.dem) and polar data
             plot (poldat.dem).



             [1m84.58.  Print[0m


             The [1mset print [22mcommand redirects the output of the [1mprint[0m
             command to a file.

             Syntax:
                   set print
                   set print "-"
                   set print "<filename>"
                   set print "<filename>" append
                   set print "|<shell_command>"

             Without "<filename>", the output file is restored to
             <STDERR>.  The <filename> "-" means <STDOUT>. The [1mappend[0m
             flag causes the file to be opened in append mode.  A
             <filename> starting with "|" is opened as a pipe to the
             <shell_command> on platforms that support piping.



             [1m84.59.  Psdir[0m


             The [1mset psdir <directory> [22mcommand controls the search path
             used by the postscript terminal to find prologue.ps and
             character encoding files.  You can use this mechanism to
             switch between different sets of locally-customized prolog
             files.  The search order is
                   1) The directory specified by `set psdir`, if any
                   2) The directory specified by environmental variable
             GNUPLOT_PS_DIR
                   3) A built-in header or one from the default system
             directory
                   4) Directories set by `set loadpath`














   GNUPLOT 4.1                                                      213


             [1m84.60.  Raxis[0m


             The commands [1mset raxis [22mand [1munset raxis [22mtoggle whether the
             polar axis is drawn separately from grid lines and the x
             axis.  If the minimum of the current rrange is non-zero
             (and not autoscaled), then a white circle is drawn at the
             center of the polar plot to indicate that the plot lines
             and axes do not reach 0.  The axis line is drawn using the
             same line type as the plot border.  See [1mpolar[22m, [1mrrange[22m,
             [1mrtics[22m, [1mset grid[22m.



             [1m84.61.  Rmargin[0m


             The command [1mset rmargin [22msets the size of the right margin.
             Please see [1mset margin [22mfor details.



             [1m84.62.  Rrange[0m


             The [1mset rrange [22mcommand sets the range of the radial coor-
             dinate for a graph in polar mode.  This has the effect of
             setting both xrange and yrange as well.  The resulting
             xrange and yrange are both [-(rmax-rmin) : +(rmax-rmin)].
             However if you later change the x or y range, for example
             by zooming, this does not change rrange, so data points
             continue to be clipped against rrange.  Autoscaling of
             rmin always results in rmin = 0.



             [1m84.63.  Rtics[0m


             The [1mset rtics [22mcommand places tics along the polar axis.
             These will only be shown in polar plot mode.  The tics and
             labels are drawn to the right of the origin. The [1mmirror[0m
             keyword causes them to be drawn also to the left of the
             origin. See [1mpolar[22m, and see [1mset xtics [22mfor discussion of
             other keywords.



             [1m84.64.  Samples[0m


             The sampling rate of functions, or for interpolating data,
             may be changed by the [1mset samples [22mcommand.










   GNUPLOT 4.1                                                      214


             Syntax:
                   set samples <samples_1> {,<samples_2>}
                   show samples

             By default, sampling is set to 100 points.  A higher sam-
             pling rate will produce more accurate plots, but will take
             longer.  This parameter has no effect on data file plot-
             ting unless one of the interpolation/approximation options
             is used.  See [1mplot smooth [22mre 2D data and [1mset cntrparam [22mand
             [1mset dgrid3d [22mre 3D data.

             When a 2D graph is being done, only the value of <sam-
             ples_1> is relevant.

             When a surface plot is being done without the removal of
             hidden lines, the value of samples specifies the number of
             samples that are to be evaluated for the isolines.  Each
             iso-v line will have <sample_1> samples and each iso-u
             line will have <sample_2> samples.  If you only specify
             <samples_1>, <samples_2> will be set to the same value as
             <samples_1>.  See also [1mset isosamples[22m.



             [1m84.65.  Size[0m


             Syntax:
                   set size {{no}square | ratio <r> | noratio}
             {<xscale>,<yscale>}
                   show size

             The <xscale> and <yscale> values are scale factors for the
             size of the plot, which includes the graph, labels, and
             margins.

             Important note:
                   In earlier versions of gnuplot, some terminal types
             used the values from
                   `set size` to control also the size of the output
             canvas; others did not.
                   In version 4.6 almost all terminals now follow the
             following convention:

             [1mset term <terminal_type> size <XX>, <YY> [22mcontrols the size
             of the output file, or [1mcanvas[22m. Please see individual ter-
             minal documentation for allowed values of the size parame-
             ters.  By default, the plot will fill this canvas.

             [1mset size <XX>, <YY> [22mscales the plot itself relative to the
             size of the canvas.  Scale values less than 1 will cause
             the plot to not fill the entire canvas.  Scale values
             larger than 1 will cause only a portion of the plot to fit










   GNUPLOT 4.1                                                      215


             on the canvas.  Please be aware that setting scale values
             larger than 1 may cause problems on some terminal types.

             [1mratio [22mcauses [1mgnuplot [22mto try to create a graph with an
             aspect ratio of <r> (the ratio of the y-axis length to the
             x-axis length) within the portion of the plot specified by
             <xscale> and <yscale>.

             The meaning of a negative value for <r> is different.  If
             <r>=-1, gnuplot tries to set the scales so that the unit
             has the same length on both the x and y axes.  This is
             equivalent to [1mset view equal xy[22m.  See [1mset view equal[22m.  If
             <r>=-2, the unit on y has twice the length of the unit on
             x, and so on.

             The success of [1mgnuplot [22min producing the requested aspect
             ratio depends on the terminal selected.  The graph area
             will be the largest rectangle of aspect ratio <r> that
             will fit into the specified portion of the output (leaving
             adequate margins, of course).

             [1msquare [22mis a synonym for [1mratio 1[22m.

             Both [1mnoratio [22mand [1mnosquare [22mreturn the graph to the default
             aspect ratio of the terminal, but do not return <xscale>
             or <yscale> to their default values (1.0).

             [1mratio [22mand [1msquare [22mhave no effect on 3D plots, but do affect
             3D projections created using [1mset view map[22m.  See also [1mset[0m
             [1mview equal[22m, which forces the x and y axes of a 3D onto the
             same scale.

             Examples:

             To set the size so that the plot fills the available can-
             vas:
                   set size 1,1

             To make the graph half size and square use:
                   set size square 0.5,0.5

             To make the graph twice as high as wide use:
                   set size ratio 2




             [1m84.66.  Style[0m


             Default plotting styles are chosen with the [1mset style data[0m
             and [1mset style function [22mcommands.  See [1mplot with [22mfor infor-
             mation about how to override the default plotting style










   GNUPLOT 4.1                                                      216


             for individual functions and data sets.  See [1mplotting[0m
             [1mstyles [22mfor a complete list of styles.

             Syntax:
                   set style function <style>
                   set style data <style>
                   show style function
                   show style data

             Default styles for specific plotting elements may also be
             set.

             Syntax:
                   set style arrow <n> <arrowstyle>
                   set style fill <fillstyle>
                   set style histogram <histogram style options>
                   set style line <n> <linestyle>

             If [1mgnuplot [22mwas built with the support of objects, then the
             following options are also available:

             Syntax:
                   set style rectangle <object options> <linestyle>
             <fillstyle>
                   set style circle radius <size>
                   set style ellipse size <size> units {xy|xx|yy}





                  [1m84.66.1.  Set style arrow[0m


                  Each terminal has a default set of arrow and point
                  types, which can be seen by using the command [1mtest[22m.
                  [1mset style arrow [22mdefines a set of arrow types and
                  widths and point types and sizes so that you can
                  refer to them later by an index instead of repeating
                  all the information at each invocation.

                  Syntax:
                        set style arrow <index> default
                        set style arrow <index> {nohead | head | heads}
                                                {size
                  <length>,<angle>{,<backangle>}}
                                                {filled | empty |
                  nofilled}
                                                {front | back}
                                                { {linestyle | ls
                  <line_style>}
                                                  | {linetype | lt
                  <line_type>}










   GNUPLOT 4.1                                                      217


                                                    {linewidth | lw
                  <line_width} }
                        unset style arrow
                        show style arrow

                  <index> is an integer that identifies the arrowstyle.

                  If [1mdefault [22mis given all arrow style parameters are
                  set to their default values.

                  If the linestyle <index> already exists, only the
                  given parameters are changed while all others are
                  preserved.  If not, all undefined values are set to
                  the default values.

                  Specifying [1mnohead [22mproduces arrows drawn without a
                  head---a line segment.  This gives you yet another
                  way to draw a line segment on the plot.  By default,
                  arrows have one head. Specifying [1mheads [22mdraws arrow
                  heads on both ends of the line.

                  Head size can be controlled by [1msize <length>,<angle>[0m
                  or [1msize <length>,<angle>,<backangle>[22m, where [1m<length>[0m
                  defines length of each branch of the arrow head and
                  [1m<angle> [22mthe angle (in degrees) they make with the
                  arrow.  [1m<Length> [22mis in x-axis units; this can be
                  changed by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter[0m
                  before the <length>;  see [1mcoordinates [22mfor details.
                  [1m<Backangle> [22monly takes effect when [1mfilled [22mor [1mempty [22mis
                  also used.  Then, [1m<backangle> [22mis the angle (in
                  degrees) the back branches make with the arrow (in
                  the same direction as [1m<angle>[22m).  The [1mfig [22mterminal has
                  a restricted backangle function. It supports three
                  different angles. There are two thresholds: Below 70
                  degrees, the arrow head gets an indented back angle.
                  Above 110 degrees, the arrow head has an acute back
                  angle. Between these thresholds, the back line is
                  straight.

                  Specifying [1mfilled [22mproduces filled arrow heads (if
                  heads are used).  Filling is supported on filled-
                  polygon capable terminals, see help of [1mpm3d [22mfor their
                  list, otherwise the arrow heads are closed but not
                  filled.  The same result (closed but not filled arrow
                  head) is reached by specifying [1mempty[22m.  Further, fill-
                  ing and outline is obviously not supported on termi-
                  nals drawing arrows by their own specific routines,
                  like [1mmetafont[22m, [1mmetapost[22m, [1mlatex [22mor [1mtgif[22m.

                  The line style may be selected from a user-defined
                  list of line styles (see [1mset style line[22m) or may be
                  defined here by providing values for [1m<line_type> [22m(an
                  index from the default list of styles) and/or










   GNUPLOT 4.1                                                      218


                  [1m<line_width> [22m(which is a  multiplier for the default
                  width).

                  Note, however, that if a user-defined line style has
                  been selected, its properties (type and width) cannot
                  be altered merely by issuing another [1mset style arrow[0m
                  command with the appropriate index and [1mlt [22mor [1mlw[22m.

                  If [1mfront [22mis given, the arrows are written on top of
                  the graphed data. If [1mback [22mis given (the default), the
                  arrow is written underneath the graphed data.  Using
                  [1mfront [22mwill prevent a arrow from being obscured by
                  dense data.

                  Examples:

                  To draw an arrow without an arrow head and double
                  width, use:
                        set style arrow 1 nohead lw 2
                        set arrow arrowstyle 1

                  See also [1mset arrow [22mfor further examples.




                  [1m84.66.2.  Boxplot[0m


                  The [1mset style boxplot [22mcommand allows you to change
                  the layout of plots created using the [1mboxplot [22mplot
                  style.

                  Syntax:
                        set style boxplot {range <r> | fraction <f>}
                                          {{no}outliers} {pointtype
                  <p>}
                                          {candlesticks | financebars}
                                          {separation <x>}
                                          {labels off | auto | x | x2}
                                          {sorted | unsorted}

                  The box in the boxplot always spans the range of val-
                  ues from the first quartile to the third quartile of
                  the data points.  The limit of the whiskers that
                  extend from the box can be controlled in two differ-
                  ent ways. By default the whiskers extend from each
                  end of the box for a range equal to 1.5 times the
                  interquartile range (i.e. the vertical height of the
                  box proper).  Each whisker is truncated back toward
                  the median so that it terminates at a y value belong-
                  ing to some point in the data set. Since there may be
                  no point whose value is exactly 1.5 times the










   GNUPLOT 4.1                                                      219


                  interquartile distance, the whisker may be shorter
                  than its nominal range.  This default corresponds to
                        set style boxplot range 1.5

                  Alternatively, you can specify the fraction of the
                  total number of points that the whiskers should span.
                  In this case the range is extended symmetrically from
                  the median value until it encompasses the requested
                  fraction of the data set.  Here again each whisker is
                  constrained to end at a point in the data set.  To
                  span 95% of the points in the set
                        set style boxplot fraction 0.95

                  Any points that lie outside the range of the whiskers
                  are considered outliers.  By default these are drawn
                  as individual circles (pointtype 7).  The option
                  [1mnooutliers [22mdisables this.

                  By default boxplots are drawn in a style similar to
                  candlesticks, but you have the option of using
                  instead a style similar to finance bars.

                  If the using specification for a boxplot contains a
                  fourth column, the values in that column will be
                  interpreted as the discrete leveles of a factor vari-
                  able.  In this case more than one boxplots may be
                  drawn, as many as the number of levels of the factor
                  variable.  These boxplots will be drawn next to each
                  other, the distance between them is 1.0 by default
                  (in x-axis units).  This distance can be changed by
                  the option [1mseparation[22m.

                  The [1mlabels [22moption governs how and where these box-
                  plots (each representing a part of the dataset) are
                  labeled.  By default the value of the factor is put
                  as a tick label on the horizontal axis -- x or x2,
                  depending on which one is used for the plot itself.
                  This setting corresponds to option [1mlabels auto[22m.  The
                  labels can be forced to use either of the x or x2
                  axes -- options [1mlabels x [22mand [1mlabels x2[22m, respectively
                  --, or they can be turned off altogether with the
                  option [1mlabels off[22m.

                  By default the boxplots corresponding to different
                  levels of the factor variable are not sorted; they
                  will be drawn in the same order the levels are
                  encountered in the data file. This behavior corre-
                  sponds to the [1munsorted [22moption. If the [1msorted [22moption
                  is active, the levels are first sorted alphabeti-
                  cally, and the boxplots are drawn in the sorted
                  order.

                  The [1mseparation[22m, [1mlabels[22m, [1msorted [22mand [1munsorted [22moption










   GNUPLOT 4.1                                                      220


                  only have an effect if a fourth column is given the
                  plot specification.

                  See [1mboxplot[22m, [1mcandlesticks[22m, [1mfinancebars[22m.




                  [1m84.66.3.  Set style data[0m


                  The [1mset style data [22mcommand changes the default plot-
                  ting style for data plots.

                  Syntax:
                        set style data <plotting-style>
                        show style data

                  See [1mplotting styles [22mfor the choices.  If no choice is
                  given, the choices are listed.  [1mshow style data [22mshows
                  the current default data plotting style.



                  [1m84.66.4.  Set style fill[0m


                  The [1mset style fill [22mcommand is used to set the default
                  style of the plot elements in plots with boxes, his-
                  tograms, candlesticks and filledcurves.  This default
                  can be superseded by fillstyles attached to individ-
                  ual plots.  See also 'set style rectangle'.

                  Syntax:
                        set style fill {empty
                                        | {transparent} solid {<den-
                  sity>}
                                        | {transparent} pattern {<n>}}
                                       {border {lt} {lc <colorspec>} |
                  noborder}

                  The default fillstyle is [1mempty[22m.

                  The [1msolid [22moption causes filling with a solid color,
                  if the terminal supports that. The <density> parame-
                  ter specifies the intensity of the fill color. At a
                  <density> of 0.0, the box is empty, at <density> of
                  1.0, the inner area is of the same color as the cur-
                  rent linetype.  Some terminal types can vary the den-
                  sity continuously; others implement only a few levels
                  of partial fill.  If no <density> parameter is given,
                  it defaults to 1.











   GNUPLOT 4.1                                                      221


                  The [1mpattern [22moption causes filling to be done with a
                  fill pattern supplied by the terminal driver.  The
                  kind and number of available fill patterns depend on
                  the terminal driver.  If multiple datasets using
                  filled boxes are plotted, the pattern cycles through
                  all available pattern types, starting from pattern
                  <n>, much as the line type cycles for multiple line
                  plots.

                  The [1mempty [22moption causes filled boxes not to be
                  filled. This is the default.

                  By default, [1mborder[22m, the box is bounded by a solid
                  line of the current linetype. [1mborder <colorspec>[0m
                  allows you to change the color of the border.  [1mnobor-[0m
                  [1mder [22mspecifies that no bounding lines are drawn.




                       [1m84.66.4.1.  Set style fill transparent[0m


                       Some terminals support the attribute [1mtransparent[0m
                       for filled areas.  In the case of transparent
                       solid fill areas, the [1mdensity [22mparameter is
                       interpreted as an alpha value; that is, density
                       0 is fully transparent, density 1 is fully
                       opaque.  In the case of transparent pattern
                       fill, the background of the pattern is either
                       fully transparent or fully opaque.




                          +---------------------+
                          |Terminal   solid     |
                          +---------------------+
                          |  gif      no        |
                          |  jpeg     yes       |
                          |  pdf      yes       |
                          |  png      TrueColor |
                          |  post     no        |
                          |  svg      yes       |
                          |  win      yes       |
                          |  wxt      yes       |
                          |  x11      no        |
                          +---------------------+
                          +---------------------+














   GNUPLOT 4.1                                                      222


   Note that there may be additional limitations on the creation or
   viewing of graphs containing transparent fill areas.  For example,
   the png terminal can only use transparent fill if the "truecolor"
   option is set.  Some pdf viewers may not correctly display the fill
   areas even if they are correctly described in the pdf file.
   Ghostscript/gv does not correctly display pattern-fill areas even
   though actual PostScript printers generally have no problem.



                  [1m84.66.5.  Set style function[0m


                  The [1mset style function [22mcommand changes the default
                  plotting style for function plots (e.g. lines,
                  points, filledcurves).  See [1mplotting styles[22m.

                  Syntax:
                        set style function <plotting-style>
                        show style function



                  [1m84.66.6.  Set style increment[0m


                  [1mNote[22m:  This command has been deprecated.  Instead
                  please use the newer command [1mset linetype[22m, which
                  redefines the linetypes themselves rather than
                  searching for a suitable temporary line style to sub-
                  stitute.  See [1mset linetype[0m

                  Syntax:
                        set style increment {default|userstyles}
                        show style increment

                  By default, successive plots within the same graph
                  will use successive linetypes from the default set
                  for the current terminal type.  However, choosing [1mset[0m
                  [1mstyle increment user [22mallows you to step through the
                  user-defined line styles rather than through the
                  default linetypes.

                  Example:

                        set style line 1 lw 2 lc rgb "gold"
                        set style line 2 lw 2 lc rgb "purple"
                        set style line 4 lw 1 lc rgb "sea-green"
                        set style increment user

                        plot f1(x), f2(x), f3(x), f4(x)

                  should plot functions f1, f2, f4 in your 3 newly










   GNUPLOT 4.1                                                      223


                  defined line styles.  If a user-defined line style is
                  not found then the corresponding default linetype is
                  used instead.  E.g. in the example above, f3(x) will
                  be plotted using the default linetype 3.




                  [1m84.66.7.  Set style line[0m


                  Each terminal has a default set of line and point
                  types, which can be seen by using the command [1mtest[22m.
                  [1mset style line [22mdefines a set of line types and widths
                  and point types and sizes so that you can refer to
                  them later by an index instead of repeating all the
                  information at each invocation.

                  Syntax:
                        set style line <index> default
                        set style line <index> {{linetype  | lt}
                  <line_type> | <colorspec>}
                                               {{linecolor | lc} <col-
                  orspec>}
                                               {{linewidth | lw}
                  <line_width>}
                                               {{pointtype | pt}
                  <point_type>}
                                               {{pointsize | ps}
                  <point_size>}
                                               {{pointinterval | pi}
                  <interval>}
                                               {palette}
                        unset style line
                        show style line

                  [1mdefault [22msets all line style parameters to those of
                  the linetype with that same index.

                  If the linestyle <index> already exists, only the
                  given parameters are changed while all others are
                  preserved.  If not, all undefined values are set to
                  the default values.

                  Line styles created by this mechanism do not replace
                  the default linetype styles; both may be used.  Line
                  styles are temporary. They are lost whenever you exe-
                  cute a [1mreset [22mcommand.  To redefine the linetype
                  itself, please see [1mset linetype[22m.

                  The line and point types default to the index value.
                  The exact symbol that is drawn for that index value
                  may vary from one terminal type to another.










   GNUPLOT 4.1                                                      224


                  The line width and point size are multipliers for the
                  current terminal's default width and size (but note
                  that <point_size> here is unaffected by the multi-
                  plier given by the command[1mset pointsize[22m).

                  The [1mpointinterval [22mcontrols the spacing between points
                  in a plot drawn with style [1mlinespoints[22m.  The default
                  is 0 (every point is drawn). For example, [1mset style[0m
                  [1mline N pi 3 [22mdefines a linestyle that uses pointtype
                  N, pointsize and linewidth equal to the current
                  defaults for the terminal, and will draw every 3rd
                  point in plots using [1mwith linespoints[22m.  A negative
                  value for the interval is treated the same as a posi-
                  tive value, except that some terminals will try to
                  interrupt the line where it passes through the point
                  symbol.

                  Not all terminals support the [1mlinewidth [22mand [1mpointsize[0m
                  features; if not supported, the option will be
                  ignored.

                  Terminal-independent colors may be assigned using
                  either [1mlinecolor <colorspec> [22mor [1mlinetype <colorspec>[22m,
                  abbreviated [1mlc [22mor [1mlt[22m.  This requires giving a RGB
                  color triple, a known palette color name, a frac-
                  tional index into the current palette, or a constant
                  value from the current mapping of the palette onto
                  cbrange.  See [1mcolors[22m, [1mcolorspec[22m, [1mset palette[22m, [1mcolor-[0m
                  [1mnames[22m, [1mcbrange[22m.

                  [1mset style line <n> linetype <lt> [22mwill set both a ter-
                  minal-dependent dot/dash pattern and color. The com-
                  mands[1mset style line <n> linecolor <colorspec> [22mor [1mset[0m
                  [1mstyle line <n> linetype <colorspec> [22mwill set a new
                  line color while leaving the existing dot-dash pat-
                  tern unchanged.

                  In 3d mode ([1msplot [22mcommand), the special keyword
                  [1mpalette [22mis allowed as a shorthand for "linetype
                  palette z".  The color value corresponds to the z-
                  value (elevation) of the splot, and varies smoothly
                  along a line or surface.

                  Examples: Suppose that the default lines for indices
                  1, 2, and 3 are red, green, and blue, respectively,
                  and the default point shapes for the same indices are
                  a square, a cross, and a triangle, respectively.
                  Then

                        set style line 1 lt 2 lw 2 pt 3 ps 0.5

                  defines a new linestyle that is green and twice the
                  default width and a new pointstyle that is a half-










   GNUPLOT 4.1                                                      225


                  sized triangle.  The commands

                        set style function lines
                        plot f(x) lt 3, g(x) ls 1

                  will create a plot of f(x) using the default blue
                  line and a plot of g(x) using the user-defined wide
                  green line.  Similarly the commands

                        set style function linespoints
                        plot p(x) lt 1 pt 3, q(x) ls 1

                  will create a plot of p(x) using the default trian-
                  gles connected by a red line and q(x) using small
                  triangles connected by a green line.

                        splot sin(sqrt(x*x+y*y))/sqrt(x*x+y*y) w l pal

                  creates a surface plot using smooth colors according
                  to [1mpalette[22m. Note, that this works only on some termi-
                  nals. See also [1mset palette[22m, [1mset pm3d[22m.

                        set style line 10 linetype 1 linecolor rgb
                  "cyan"

                  will assign linestyle 10 to be a solid cyan line on
                  any terminal that supports rgb colors.




                  [1m84.66.8.  Set style circle[0m



                  Syntax:
                        set style circle {radius {graph|screen} <R>}

                  This command sets the default radius used in plot
                  style "with circles".  It applies to data plots with
                  only 2 columns of data (x,y) and to function plots.
                  The default is "set style circle radius graph 0.02".




                  [1m84.66.9.  Set style rectangle[0m



                  Rectangles defined with the [1mset object [22mcommand can
                  have individual styles.  However, if the object is
                  not assigned a private style then it inherits a










   GNUPLOT 4.1                                                      226


                  default that is taken from the [1mset style rectangle[0m
                  command.

                  Syntax:
                      set style rectangle {front|back} {lw|linewidth
                  <lw>}
                                          {fillcolor <colorspec>} {fs
                  <fillstyle>}

                  See [1mcolorspec [22mand [1mfillstyle[22m.  [1mfillcolor [22mmay be abbre-
                  viated as [1mfc[22m.

                  Examples:
                      set style rectangle back fc rgb "white" fs solid
                  1.0 border lt -1
                      set style rectangle fc linsestyle 3 fs pattern 2
                  noborder

                  The default values correspond to solid fill with the
                  background color and a black border.




                  [1m84.66.10.  Set style ellipse[0m



                  Syntax:
                        set style ellipse {units xx|xy|yy}
                                          {size {graph|screen} <a>,
                  {{graph|screen} <b>}}
                                          {angle <angle>}

                  This command governs whether the diameters of
                  ellipses are interpreted in the same units or not.
                  Default is [1mxy[22m, which means that the major diameter
                  (first axis) of ellipses will be interpreted in the
                  same units as the x (or x2) axis, while the minor
                  (second) diameter in those of the y (or y2) axis.  In
                  this mode the ratio of the ellipse axes depends on
                  the scales of the plot axes and aspect ratio of the
                  plot.  When set to [1mxx [22mor [1myy[22m, both axes of all
                  ellipses will be interpreted in the same units.  This
                  means that the ratio of the axes of the plotted
                  ellipses will be correct even after rotation, but
                  either their vertical or horizontal extent will not
                  be correct.

                  This is a global setting that affects all ellipses,
                  both those defined as objects and those generated
                  with the [1mplot [22mcommand, however, the value of [1munits[0m
                  can also be redefined on a per-plot and per-object










   GNUPLOT 4.1                                                      227


                  basis.

                  It is also possible to set a default size for
                  ellipses with the [1msize [22mkeyword.  This default size
                  applies to data plots with only 2 columns of data
                  (x,y) and to function plots.  The two values are
                  interpreted as the major and minor diameters (as
                  opposed to semi-major and semi-minor axes) of the
                  ellipse.

                  The default is "set style ellipse size graph
                  0.05,0.03".

                  Last, but not least it is possible to set the default
                  orientation with the [1mangle [22mkeyword. The orientation,
                  which is defined as the angle between the major axis
                  of the ellipse and the plot's x axis, must be given
                  in degrees.

                  For defining ellipse objects, see [1mset object ellipse[22m;
                  for the 2D plot style, see [1mellipses[22m.




             [1m84.67.  Surface[0m


             The command [1mset surface [22mcontrols the display of surfaces
             by [1msplot[22m.

             Syntax:
                   set surface
                   unset surface
                   show surface

             The surface is drawn with the style specified by [1mwith[22m, or
             else the appropriate style, data or function.

             [1munset surface [22mwill cause [1msplot [22mto not draw points or lines
             corresponding to any of the function or data file points.
             If you want to turn off the surface for an individual
             function or data file while leaving the others active, use
             the [1mnosurface [22mkeyword in the [1msplot [22mcommand.  Contours may
             still be drawn on the surface, depending on the [1mset con-[0m
             [1mtour [22moption.  The combination [1munset surface; set contour[0m
             [1mbase [22mis useful for displaying contours on the grid base.
             See also [1mset contour[22m.















   GNUPLOT 4.1                                                      228


             [1m84.68.  Table[0m


             When [1mtable [22mmode is enabled, [1mplot [22mand [1msplot [22mcommands print
             out a multicolumn ASCII table of X Y {Z} R values rather
             than creating an actual plot on the current terminal.  The
             character R takes on one of three values: "i" if the point
             is in the active range, "o" if it is out-of-range, or "u"
             if it is undefined.  The data format is determined by the
             format of the axis labels (see [1mset format[22m), and the col-
             umns are separated by single spaces.  This can be useful
             if you want to generate contours and then save them for
             further use, perhaps for plotting with [1mplot[22m;  see [1mset con-[0m
             [1mtour [22mfor example.  The same method can be used to save
             interpolated data (see [1mset samples [22mand [1mset dgrid3d[22m).

             Syntax:
                   set table {"outfile"}
                   plot <whatever>
                   unset table

             Tabular output is written to the named file, if any, oth-
             erwise it is written to the current value of [1mset output[22m.
             You must explicitly [1munset table [22min order to go back to
             normal plotting on the current terminal.



             [1m84.69.  Terminal[0m


             [1mgnuplot [22msupports many different graphics devices.  Use [1mset[0m
             [1mterminal [22mto tell [1mgnuplot [22mwhat kind of output to generate.
             Use [1mset output [22mto redirect that output to a file or
             device.

             Syntax:
                   set terminal {<terminal-type> | push | pop}
                   show terminal

             If <terminal-type> is omitted, [1mgnuplot [22mwill list the
             available terminal types.  <terminal-type> may be abbrevi-
             ated.

             If both [1mset terminal [22mand [1mset output [22mare used together, it
             is safest to give [1mset terminal [22mfirst, because some termi-
             nals set a flag which is needed in some operating systems.

             Some terminals have many additional options.  The options
             used by a previous invocation [1mset term <term> <options> [22mof
             a given [1m<term> [22mare remembered, thus subsequent [1mset term[0m
             [1m<term> [22mdoes not reset them.  This helps in printing, for
             instance, when switching among different










   GNUPLOT 4.1                                                      229


             terminals---previous options don't have to be repeated.

             The command [1mset term push [22mremembers the current terminal
             including its settings while [1mset term pop [22mrestores it.
             This is equivalent to [1msave term [22mand [1mload term[22m, but without
             accessing the filesystem. Therefore they can be used to
             achieve platform independent restoring of the terminal
             after printing, for instance. After gnuplot's startup, the
             default terminal or that from [1mstartup [22mfile is pushed auto-
             matically. Therefore portable scripts can rely that [1mset[0m
             [1mterm pop [22mrestores the default terminal on a given platform
             unless another terminal has been pushed explicitly.

             For more information, see the [1mcomplete list of terminals[22m.




             [1m84.70.  Termoption[0m


             The [1mset termoption [22mcommand allows you to change the behav-
             iour of the current terminal without requiring a new [1mset[0m
             [1mterminal [22mcommand. Only one option can be changed per com-
             mand, and only a small number of options can be changed
             this way. Currently the only options accepted are

                  set termoption {no}enhanced
                  set termoption font "<fontname>{,<fontsize>}"
                  set termoption fontscale <scale>
                  set termoption {solid|dashed}
                  set termoption {linewidth <lw>}{lw <lw>}




             [1m84.71.  Tics[0m


             Control of the major (labelled) tics on all axes at once
             is possible with the [1mset tics [22mcommand.

             Fine control of the major (labelled) tics on all axes at
             once is possible with the [1mset tics [22mcommand.  The tics may
             be turned off with the [1munset tics [22mcommand, and may be
             turned on (the default state) with [1mset tics[22m.  Similar com-
             mands (by preceding 'tics' by the axis name) control the
             major tics on a single axis.

             Syntax:
                   set tics {axis | border} {{no}mirror}
                            {in | out} {scale {default | <major>
             {,<minor>}}}










   GNUPLOT 4.1                                                      230


                            {{no}rotate {by <ang>}} {offset <offset> |
             nooffset}
                            {left | right | center | autojustify}
                            { format "formatstring" } { font
             "name{,<size>}" }
                            { textcolor <colorspec> }
                   set tics {front | back}
                   unset tics
                   show tics

             The options in the first set above can be applied individ-
             ually to any or all axes, i.e., x, y, z, x2, y2, and cb.

             Set tics [1mfront [22mor [1mback [22mapplies to all axes at once, but
             only for 2D plots (not splot).  It controls whether the
             tics are placed behind or in front of the plot elements,
             in the case that there is overlap.

             [1maxis [22mor [1mborder [22mtells [1mgnuplot [22mto put the tics (both the
             tics themselves and the accompanying labels) along the
             axis or the border, respectively.  If the axis is very
             close to the border, the [1maxis [22moption will move the tic
             labels to outside the border in case the border is printed
             (see [1mset border[22m).  The relevant margin settings will usu-
             ally be sized badly by the automatic layout algorithm in
             this case.

             [1mmirror [22mtells [1mgnuplot [22mto put unlabelled tics at the same
             positions on the opposite border.  [1mnomirror [22mdoes what you
             think it does.

             [1min [22mand [1mout [22mchange the tic marks to be drawn inwards or
             outwards.

             With [1mscale[22m, the size of the tic marks can be adjusted. If
             <minor> is not specified, it is 0.5*<major>.  The default
             size 1.0 for major tics and 0.5 for minor tics is
             requested by [1mscale default[22m.

             [1mrotate [22masks [1mgnuplot [22mto rotate the text through 90 degrees,
             which will be done if the terminal driver in use supports
             text rotation.  [1mnorotate [22mcancels this. [1mrotate by <ang>[0m
             asks for rotation by <ang> degrees, supported by some ter-
             minal types.

             The defaults are [1mborder mirror norotate [22mfor tics on the x
             and y axes, and [1mborder nomirror norotate [22mfor tics on the
             x2 and y2 axes.  For the z axis, the default is [1mnomirror[22m.

             The <offset> is specified by either x,y or x,y,z, and may
             be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter[0m
             to select the coordinate system. <offset> is the offset of
             the tics texts from their default positions, while the










   GNUPLOT 4.1                                                      231


             default coordinate system is [1mcharacter[22m.  See [1mcoordinates[0m
             for details. [1mnooffset [22mswitches off the offset.

             By default, tic labels are justified automatically depend-
             ing on the axis and rotation angle to produce aestheti-
             cally pleasing results. If this is not desired, justifica-
             tion can be overridden with an explicit [1mleft[22m, [1mright [22mor
             [1mcenter [22mkeyword. [1mautojustify [22mrestores the default behavior.

             [1mset tics [22mwith no options restores to place tics inwards.
             Every other options are retained.

             See also [1mset xtics [22mfor more control of major (labelled)
             tic marks and [1mset mxtics [22mfor control of minor tic marks.
             These commands provide control at a axis by axis basis.



             [1m84.72.  Ticslevel[0m


             Deprecated. See [1mset xyplane[22m.



             [1m84.73.  Ticscale[0m


             The [1mset ticscale [22mcommand is deprecated, use [1mset tics scale[0m
             instead.



             [1m84.74.  Timestamp[0m


             The command [1mset timestamp [22mplaces the time and date of the
             plot in the left margin.

             Syntax:
                   set timestamp {"<format>"} {top|bottom} {{no}rotate}
                                 {offset <xoff>{,<yoff>}} {font
             "<fontspec>"}
                   unset timestamp
                   show timestamp

             The format string allows you to choose the format used to
             write the date and time.  Its default value is what asc-
             time() uses: "%a %b %d %H:%M:%S %Y" (weekday, month name,
             day of the month, hours, minutes, seconds, four-digit
             year).  With [1mtop [22mor [1mbottom [22myou can place the timestamp at
             the top or bottom of the left margin (default: bottom).
             [1mrotate [22mlets you write the timestamp vertically, if your










   GNUPLOT 4.1                                                      232


             terminal supports vertical text.  The constants <xoff> and
             <yoff> are offsets that let you adjust the position more
             finely.  <font> is used to specify the font with which the
             time is to be written.

             The abbreviation [1mtime [22mmay be used in place of [1mtimestamp[22m.

             Example:
                   set timestamp "%d/%m/%y %H:%M" offset 80,-2 font
             "Helvetica"

             See [1mset timefmt [22mfor more information about time format
             strings.



             [1m84.75.  Timefmt[0m


             This command applies to timeseries where data are composed
             of dates/times.  It has no meaning unless the command [1mset[0m
             [1mxdata time [22mis given also.

             Syntax:
                   set timefmt "<format string>"
                   show timefmt

             The string argument tells [1mgnuplot [22mhow to read timedata
             from the datafile.  The valid formats are:




     +---------------------------------------------------------------+
     |Format   Explanation                                           |
     +---------------------------------------------------------------+
     |  %d     day of the month, 1--31                               |
     |  %m     month of the year, 1--12                              |
     |  %y     year, 0--99                                           |
     |  %Y     year, 4-digit                                         |
     |  %j     day of the year, 1--365                               |
     |  %H     hour, 0--24                                           |
     |  %M     minute, 0--60                                         |
     |  %s     seconds since the Unix epoch (1970-01-01 00:00 UTC)   |
     |  %S     second, integer 0--60 on output, (double) on input    |
     |  %b     three-character abbreviation of the name of the month |
     |  %B     name of the month                                     |
     +---------------------------------------------------------------+
     +---------------------------------------------------------------+














   GNUPLOT 4.1                                                      233


   Any character is allowed in the string, but must match exactly.  \t
   (tab) is recognized.  Backslash-octals (\nnn) are converted to char.
   If there is no separating character between the time/date elements,
   then %d, %m, %y, %H, %M and %S read two digits each.  If a decimal
   point immediately follows the field read by %S, the decimal and any
   following digits are interpreted as a fractional second.  %Y reads
   four digits. %j reads three digits.  %b requires three characters,
   and %B requires as many as it needs.

   Spaces are treated slightly differently.  A space in the string
   stands for zero or more whitespace characters in the file.  That is,
   "%H %M" can be used to read "1220" and "12     20" as well as "12
   20".

   Each set of non-blank characters in the timedata counts as one col-
   umn in the [1musing n:n [22mspecification.  Thus [1m11:11  25/12/76  21.0 [22mcon-
   sists of three columns.  To avoid confusion, [1mgnuplot [22mrequires that
   you provide a complete [1musing [22mspecification if your file contains
   timedata.

   If the date format includes the day or month in words, the format
   string must exclude this text.  But it can still be printed with the
   "%a", "%A", "%b", or "%B" specifier.  [1mgnuplot [22mwill determine the
   proper month and weekday from the numerical values.  See [1mset format[0m
   for more details about these and other options for printing time
   data.

   When reading two-digit years with %y, values 69-99 refer to the 20th
   century, while values 00-68 refer to the 21st century.   NB: This is
   in accordance with the UNIX98 spec, but conventions vary widely and
   two-digit year values are inherently ambiguous.

   See also [1mset xdata [22mand [1mtime/date [22mfor more information.

   Example:
         set timefmt "%d/%m/%Y\t%H:%M"
   tells [1mgnuplot [22mto read date and time separated by tab.  (But look
   closely at your data---what began as a tab may have been converted
   to spaces somewhere along the line; the format string must match
   what is actually in the file.)  See also time data demo.



             [1m84.76.  Title[0m


             The [1mset title [22mcommand produces a plot title that is cen-
             tered at the top of the plot.  [1mset title [22mis a special case
             of [1mset label[22m.

             Syntax:
                   set title {"<title-text>"} {offset <offset>} {font
             "<font>{,<size>}"}










   GNUPLOT 4.1                                                      234


                             {{textcolor | tc} {<colorspec> | default}}
             {{no}enhanced}
                   show title

             If <offset> is specified by either x,y or x,y,z the title
             is moved by the given offset.  It may be preceded by
             [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto select the
             coordinate system.  See [1mcoordinates [22mfor details.  By
             default, the [1mcharacter [22mcoordinate system is used.  For
             example, "[1mset title offset 0,-1[22m" will change only the y
             offset of the title, moving the title down by roughly the
             height of one character.  The size of a character depends
             on both the font and the terminal.

             <font> is used to specify the font with which the title is
             to be written; the units of the font <size> depend upon
             which terminal is used.

             [1mtextcolor <colorspec> [22mchanges the color of the text. <col-
             orspec> can be a linetype, an rgb color, or a palette map-
             ping. See help for [1mcolorspec [22mand [1mpalette[22m.

             [1mnoenhanced [22mrequests that the title not be processed by the
             enhanced text mode parser, even if enhanced text mode is
             currently active.

             [1mset title [22mwith no parameters clears the title.

             See [1msyntax [22mfor details about the processing of backslash
             sequences and the distinction between single- and double-
             quotes.



             [1m84.77.  Tmargin[0m


             The command [1mset tmargin [22msets the size of the top margin.
             Please see [1mset margin [22mfor details.



             [1m84.78.  Trange[0m


             The [1mset trange [22mcommand sets the parametric range used to
             compute x and y values when in parametric or polar modes.
             Please see [1mset xrange [22mfor details.















   GNUPLOT 4.1                                                      235


             [1m84.79.  Urange[0m


             The [1mset urange [22mand [1mset vrange [22mcommands set the parametric
             ranges used to compute x, y, and z values when in [1msplot[0m
             parametric mode.  Please see [1mset xrange [22mfor details.



             [1m84.80.  Variables[0m


             The [1mshow variables [22mcommand lists the current value of
             user-defined and internal variables. Gnuplot internally
             defines variables whose names begin with GPVAL_, MOUSE_,
             FIT_, and TERM_.

             Syntax:
                   show variables      # show variables that do not
             begin with GPVAL_
                   show variables all  # show all variables including
             those beginning GPVAL_
                   show variables NAME # show only variables beginning
             with NAME




             [1m84.81.  Version[0m


             The [1mshow version [22mcommand lists the version of gnuplot
             being run, its last modification date, the copyright hold-
             ers, and email addresses for the FAQ, the gnuplot-info
             mailing list, and reporting bugs--in short, the informa-
             tion listed on the screen when the program is invoked
             interactively.

             Syntax:
                   show version {long}

             When the [1mlong [22moption is given, it also lists the operating
             system, the compilation options used when [1mgnuplot [22mwas
             installed, the location of the help file, and (again) the
             useful email addresses.



             [1m84.82.  View[0m


             The [1mset view [22mcommand sets the viewing angle for [1msplot[22ms.
             It controls how the 3D coordinates of the plot are mapped










   GNUPLOT 4.1                                                      236


             into the 2D screen space.  It provides controls for both
             rotation and scaling of the plotted data, but supports
             orthographic projections only.  It supports both 3D pro-
             jection or orthogonal 2D projection into a 2D plot-like
             map.

             Syntax:
                   set view <rot_x>{,{<rot_z>}{,{<scale>}{,<scale_z>}}}
                   set view map
                   set view {no}equal {xy|xyz}
                   show view

             where <rot_x> and <rot_z> control the rotation angles (in
             degrees) in a virtual 3D coordinate system aligned with
             the screen such that initially (that is, before the rota-
             tions are performed) the screen horizontal axis is x,
             screen vertical axis is y, and the axis perpendicular to
             the screen is z.  The first rotation applied is <rot_x>
             around the x axis.  The second rotation applied is <rot_z>
             around the new z axis.

             Command [1mset view map [22mis used to represent the drawing as a
             map. It can be used for [1mcontour [22mplots, or for color [1mpm3d[0m
             maps. In the latter, take care that you properly use
             [1mzrange [22mand [1mcbrange [22mfor input data point filtering and
             color range scaling, respectively.

             <rot_x> is bounded to the [0:180] range with a default of
             60 degrees, while <rot_z> is bounded to the [0:360] range
             with a default of 30 degrees.  <scale> controls the scal-
             ing of the entire [1msplot[22m, while <scale_z> scales the z axis
             only.  Both scales default to 1.0.

             Examples:
                   set view 60, 30, 1, 1
                   set view ,,0.5

             The first sets all the four default values.  The second
             changes only scale, to 0.5.




                  [1m84.82.1.  Equal_axes[0m


                  The command [1mset view equal xy [22mforces the unit length
                  of the x and y axes to be on the same scale, and
                  chooses that scale so that the plot will fit on the
                  page.  The command [1mset view equal xyz [22madditionally
                  sets the z axis scale to match the x and y axes; how-
                  ever there is no guarantee that the current z axis
                  range will fit within the plot boundary.  By default










   GNUPLOT 4.1                                                      237


                  all three axes are scaled independently to fill the
                  available area.

                  See also [1mset xyplane[22m.



             [1m84.83.  Vrange[0m


             The [1mset urange [22mand [1mset vrange [22mcommands set the parametric
             ranges used to compute x, y, and z values when in [1msplot[0m
             parametric mode.  Please see [1mset xrange [22mfor details.



             [1m84.84.  X2data[0m


             The [1mset x2data [22mcommand sets data on the x2 (top) axis to
             timeseries (dates/times).  Please see [1mset xdata[22m.



             [1m84.85.  X2dtics[0m


             The [1mset x2dtics [22mcommand changes tics on the x2 (top) axis
             to days of the week.  Please see [1mset xdtics [22mfor details.



             [1m84.86.  X2label[0m


             The [1mset x2label [22mcommand sets the label for the x2 (top)
             axis.  Please see [1mset xlabel[22m.



             [1m84.87.  X2mtics[0m


             The [1mset x2mtics [22mcommand changes tics on the x2 (top) axis
             to months of the year.  Please see [1mset xmtics [22mfor details.



             [1m84.88.  X2range[0m


             The [1mset x2range [22mcommand sets the horizontal range that
             will be displayed on the x2 (top) axis.  Please see [1mset[0m










   GNUPLOT 4.1                                                      238


             [1mxrange [22mfor details.



             [1m84.89.  X2tics[0m


             The [1mset x2tics [22mcommand controls major (labelled) tics on
             the x2 (top) axis.  Please see [1mset xtics [22mfor details.



             [1m84.90.  X2zeroaxis[0m


             The [1mset x2zeroaxis [22mcommand draws a line at the origin of
             the x2 (top) axis (y2 = 0).  For details, please see [1mset[0m
             [1mzeroaxis[22m.



             [1m84.91.  Xdata[0m


             This command sets the datatype on the x axis to time/date.
             A similar command does the same thing for each of the
             other axes.

             Syntax:
                   set xdata {time}
                   show xdata

             The same syntax applies to [1mydata[22m, [1mzdata[22m, [1mx2data[22m, [1my2data[0m
             and [1mcbdata[22m.

             The [1mtime [22moption signals that the datatype is indeed
             time/date.  If the option is not specified, the datatype
             reverts to normal.

             See [1mset timefmt [22mto tell gnuplot how to read date or time
             data.  The time/date is converted to seconds from start of
             the century.  There is currently only one timefmt, which
             implies that all the time/date columns must conform to
             this format.  Specification of ranges should be supplied
             as quoted strings according to this format to avoid inter-
             pretation of the time/date as an expression.

             The function 'strftime' (type "man strftime" on unix to
             look it up) is used to print tic-mark labels.  [1mgnuplot[0m
             tries to figure out a reasonable format for this  unless
             the [1mset format x "string" [22mhas supplied something that does
             not look like a decimal format (more than one '%' or nei-
             ther %f nor %g).










   GNUPLOT 4.1                                                      239


             See also [1mtime/date [22mfor more information.



             [1m84.92.  Xdtics[0m


             The [1mset xdtics [22mcommands converts the x-axis tic marks to
             days of the week where 0=Sun and 6=Sat.  Overflows are
             converted modulo 7 to dates.  [1mset noxdtics [22mreturns the
             labels to their default values.  Similar commands do the
             same things for the other axes.

             Syntax:
                   set xdtics
                   unset xdtics
                   show xdtics

             The same syntax applies to [1mydtics[22m, [1mzdtics[22m, [1mx2dtics[22m,
             [1my2dtics [22mand [1mcbdtics[22m.

             See also the [1mset format [22mcommand.



             [1m84.93.  Xlabel[0m


             The [1mset xlabel [22mcommand sets the x axis label.  Similar
             commands set labels on the other axes.

             Syntax:
                   set xlabel {"<label>"} {offset <offset>} {font
             "<font>{,<size>}"}
                              {textcolor <colorspec>} {{no}enhanced}
                              {rotate by <degrees> | rotate parallel |
             norotate}
                   show xlabel

             The same syntax applies to [1mx2label[22m, [1mylabel[22m, [1my2label[22m, [1mzla-[0m
             [1mbel [22mand [1mcblabel[22m.

             If <offset> is specified by either x,y or x,y,z the label
             is moved by the given offset.  It may be preceded by
             [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto select the
             coordinate system.  See [1mcoordinates [22mfor details.  By
             default, the [1mcharacter [22mcoordinate system is used.  For
             example, "[1mset xlabel offset -1,0[22m" will change only the x
             offset of the title, moving the label roughly one charac-
             ter width to the left.  The size of a character depends on
             both the font and the terminal.

             <font> is used to specify the font in which the label is










   GNUPLOT 4.1                                                      240


             written; the units of the font <size> depend upon which
             terminal is used.

             [1mnoenhanced [22mrequests that the label text not be processed
             by the enhanced text mode parser, even if enhanced text
             mode is currently active.

             To clear a label, put no options on the command line,
             e.g., "[1mset y2label[22m".

             The default positions of the axis labels are as follows:

             xlabel:  The x-axis label is centered below the bottom of
             the plot.

             ylabel:  The y-axis label is centered to the left of the
             plot, defaulting to either horizontal or vertical orienta-
             tion depending on the terminal type.

             zlabel: The z-axis label is centered along the z axis and
             placed in the space above the grid level.

             cblabel: The color box axis label is centered along the
             box and placed below or to the right according to horizon-
             tal or vertical color box gradient.

             y2label: The y2-axis label is placed to the right of the
             y2 axis.  The position is terminal-dependent in the same
             manner as is the y-axis label.

             x2label: The x2-axis label is placed above the plot but
             below the title.  It is also possible to create an x2-axis
             label by using new-line characters to make a multi-line
             plot title, e.g.,

                   set title "This is the title\n\nThis is the x2label"

             Note that double quotes must be used.  The same font will
             be used for both lines, of course.

             The orientation (rotation angle) of the x, x2, y and y2
             axis labels in 2D plots can be changed by specifying
             [1mrotate by <degrees>[22m.  The orientation of the x and y axis
             labels in 3D plots defaults to horizontal but can be
             changed to run parallel to the axis by specifying [1mrotate[0m
             [1mparallel[22m.

             If you are not satisfied with the default position of an
             axis label, use [1mset label [22minstead--that command gives you
             much more control over where text is placed.

             Please see [1msyntax [22mfor further information about backslash
             processing and the difference between single- and double-










   GNUPLOT 4.1                                                      241


             quoted strings.



             [1m84.94.  Xmtics[0m


             The [1mset xmtics [22mcommand converts the x-axis tic marks to
             months of the year where 1=Jan and 12=Dec.  Overflows are
             converted modulo 12 to months.  The tics are returned to
             their default labels by [1munset xmtics[22m.  Similar commands
             perform the same duties for the other axes.

             Syntax:
                   set xmtics
                   unset xmtics
                   show xmtics

             The same syntax applies to [1mx2mtics[22m, [1mymtics[22m, [1my2mtics[22m,
             [1mzmtics [22mand [1mcbmtics[22m.

             See also the [1mset format [22mcommand.



             [1m84.95.  Xrange[0m


             The [1mset xrange [22mcommand sets the horizontal range that will
             be displayed.  A similar command exists for each of the
             other axes, as well as for the polar radius r and the
             parametric variables t, u, and v.

             Syntax:
                   set xrange { [{{<min>}:{<max>}}] {{no}reverse}
             {{no}writeback} }
                              | restore
                   show xrange

             where <min> and <max> terms are constants, expressions or
             an asterisk to set autoscaling.  See below for full
             autoscaling syntax.  If the data are time/date, you must
             give the range as a quoted string according to the [1mset[0m
             [1mtimefmt [22mformat.  Any value omitted will not be changed.

             The same syntax applies to [1myrange[22m, [1mzrange[22m, [1mx2range[22m,
             [1my2range[22m, [1mcbrange[22m, [1mrrange[22m, [1mtrange[22m, [1murange [22mand [1mvrange[22m.

             The [1mreverse [22moption reverses the direction of the axis,
             e.g., [1mset xrange [0:1] reverse [22mwill produce an axis with 1
             on the left and 0 on the right.  This is identical to the
             axis produced by [1mset xrange [1:0][22m, of course.  [1mreverse [22mis
             intended primarily for use with [1mautoscale[22m.










   GNUPLOT 4.1                                                      242


             Autoscaling:  If <min> (the same applies for correspond-
             ingly to <max>) is an asterisk "*" autoscaling is turned
             on.  The range in which autoscaling is being performed may
             be limited by a lower bound <lb> or an upper bound <ub> or
             both.  The syntax is
                   { <lb> < } * { < <ub> }
             For example,
                   0 < * < 200
             sets <lb> = 0 and <ub> = 200.  With such a setting <min>
             would be autoscaled, but its final value will be between 0
             and 200 (both inclusive despite the '<' sign).  If no
             lower or upper bound is specified, the '<' to also be
             ommited.  If <ub> is lower than <lb> the constraints will
             be turned off and full autoscaling will happen.  This fea-
             ture is useful to plot measured data with autoscaling but
             providing a limit on the range, to clip outliers, or to
             guarantee a minimum range that will be displayed even if
             the data would not need such a big range.

             The [1mwriteback [22moption essentially saves the range found by
             [1mautoscale [22min the buffers that would be filled by [1mset[0m
             [1mxrange[22m.  This is useful if you wish to plot several func-
             tions together but have the range determined by only some
             of them.  The [1mwriteback [22moperation is performed during the
             [1mplot [22mexecution, so it must be specified before that com-
             mand.  To restore, the last saved horizontal range use [1mset[0m
             [1mxrange restore[22m.  For example,

                   set xrange [-10:10]
                   set yrange [] writeback
                   plot sin(x)
                   set yrange restore
                   replot x/2

             results in a yrange of [-1:1] as found only from the range
             of sin(x); the [-5:5] range of x/2 is ignored.  Executing
             [1mshow yrange [22mafter each command in the above example should
             help you understand what is going on.

             In 2D, [1mxrange [22mand [1myrange [22mdetermine the extent of the axes,
             [1mtrange [22mdetermines the range of the parametric variable in
             parametric mode or the range of the angle in polar mode.
             Similarly in parametric 3D, [1mxrange[22m, [1myrange[22m, and [1mzrange[0m
             govern the axes and [1murange [22mand [1mvrange [22mgovern the paramet-
             ric variables.

             In polar mode, [1mrrange [22mdetermines the radial range plotted.
             <rmin> acts as an additive constant to the radius, whereas
             <rmax> acts as a clip to the radius---no point with radius
             greater than <rmax> will be plotted.  [1mxrange [22mand [1myrange[0m
             are affected---the ranges can be set as if the graph was
             of r(t)-rmin, with rmin added to all the labels.











   GNUPLOT 4.1                                                      243


             Any range may be partially or totally autoscaled, although
             it may not make sense to autoscale a parametric variable
             unless it is plotted with data.

             Ranges may also be specified on the [1mplot [22mcommand line.  A
             range given on the plot line will be used for that single
             [1mplot [22mcommand; a range given by a [1mset [22mcommand will be used
             for all subsequent plots that do not specify their own
             ranges.  The same holds true for [1msplot[22m.

             Examples:

             To set the xrange to the default:
                   set xrange [-10:10]

             To set the yrange to increase downwards:
                   set yrange [10:-10]

             To change zmax to 10 without affecting zmin (which may
             still be autoscaled):
                   set zrange [:10]

             To autoscale xmin while leaving xmax unchanged:
                   set xrange [*:]

             To autoscale xmin but keeping xmin positive:
                   set xrange [0<*:]

             To autoscale x but keep minimum range of 10 to 50 (actual
             might be larger):
                   set xrange [*<10:50<*]

             Autoscaling but limit maximum xrange to -1000 to 1000,
             i.e. autoscaling within [-1000:1000]
                   set xrange [-1000<*:*<1000]

             Make sure xmin is somewhere between -200 and 100:
                   set xrange [-200<*<100:]




             [1m84.96.  Xtics[0m


             Fine control of the major (labelled) tics on the x axis is
             possible with the [1mset xtics [22mcommand.  The tics may be
             turned off with the [1munset xtics [22mcommand, and may be turned
             on (the default state) with [1mset xtics[22m.  Similar commands
             control the major tics on the y, z, x2 and y2 axes.

             Syntax:
                   set xtics {axis | border} {{no}mirror}










   GNUPLOT 4.1                                                      244


                             {in | out} {scale {default | <major>
             {,<minor>}}}
                             {{no}rotate {by <ang>}} {offset <offset> |
             nooffset}
                             {left | right | center | autojustify}
                             {add}
                             {  autofreq
                              | <incr>
                              | <start>, <incr> {,<end>}
                              | ({"<label>"} <pos> {<level>}
             {,{"<label>"}...) }
                             { format "formatstring" } { font
             "name{,<size>}" }
                             { rangelimited }
                             { textcolor <colorspec> }
                   unset xtics
                   show xtics

             The same syntax applies to [1mytics[22m, [1mztics[22m, [1mx2tics[22m, [1my2tics[0m
             and [1mcbtics[22m.

             [1maxis [22mor [1mborder [22mtells [1mgnuplot [22mto put the tics (both the
             tics themselves and the accompanying labels) along the
             axis or the border, respectively.  If the axis is very
             close to the border, the [1maxis [22moption will move the tic
             labels to outside the border.  The relevant margin set-
             tings will usually be sized badly by the automatic layout
             algorithm in this case.

             [1mmirror [22mtells [1mgnuplot [22mto put unlabelled tics at the same
             positions on the opposite border.  [1mnomirror [22mdoes what you
             think it does.

             [1min [22mand [1mout [22mchange the tic marks to be drawn inwards or
             outwards.

             With [1mscale[22m, the size of the tic marks can be adjusted. If
             <minor> is not specified, it is 0.5*<major>.  The default
             size 1.0 for major tics and 0.5 for minor tics is
             requested by [1mscale default[22m.

             [1mrotate [22masks [1mgnuplot [22mto rotate the text through 90 degrees,
             which will be done if the terminal driver in use supports
             text rotation.  [1mnorotate [22mcancels this. [1mrotate by <ang>[0m
             asks for rotation by <ang> degrees, supported by some ter-
             minal types.

             The defaults are [1mborder mirror norotate [22mfor tics on the x
             and y axes, and [1mborder nomirror norotate [22mfor tics on the
             x2 and y2 axes.  For the z axis, the [1m{axis | border}[0m
             option is not available and the default is [1mnomirror[22m.  If
             you do want to mirror the z-axis tics, you might want to
             create a bit more room for them with [1mset border[22m.










   GNUPLOT 4.1                                                      245


             The <offset> is specified by either x,y or x,y,z, and may
             be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter[0m
             to select the coordinate system. <offset> is the offset of
             the tics texts from their default positions, while the
             default coordinate system is [1mcharacter[22m.  See [1mcoordinates[0m
             for details. [1mnooffset [22mswitches off the offset.

             Example:

             Move xtics more closely to the plot.
                   set xtics offset 0,graph 0.05

             By default, tic labels are justified automatically depend-
             ing on the axis and rotation angle to produce aestheti-
             cally pleasing results. If this is not desired, justifica-
             tion can be overridden with an explicit [1mleft[22m, [1mright [22mor
             [1mcenter [22mkeyword. [1mautojustify [22mrestores the default behavior.

             [1mset xtics [22mwith no options restores the default border or
             axis if xtics are being displayed;  otherwise it has no
             effect.  Any previously specified tic frequency or posi-
             tion {and labels} are retained.

             Positions of the tics are calculated automatically by
             default or if the [1mautofreq [22moption is given; otherwise they
             may be specified in either of two forms:

             The implicit <start>, <incr>, <end> form specifies that a
             series of tics will be plotted on the axis between the
             values <start> and <end> with an increment of <incr>.  If
             <end> is not given, it is assumed to be infinity.  The
             increment may be negative.  If neither <start> nor <end>
             is given, <start> is assumed to be negative infinity,
             <end> is assumed to be positive infinity, and the tics
             will be drawn at integral multiples of <incr>.  If the
             axis is logarithmic, the increment will be used as a mul-
             tiplicative factor.

             If you specify to a negative <start> or <incr> after a
             numerical value (e.g., [1mrotate by <angle> [22mor [1moffset <off-[0m
             [1mset>[22m), the parser fails because it subtracts <start> or
             <incr> from that value.  As a workaround, specify
             [1m0-<start> [22mresp. [1m0-<incr> [22min that case.

             Example:
                   set xtics border offset 0,0.5 -5,1,5
             Fails with 'invalid expression' at the last comma.
                   set xtics border offset 0,0.5 0-5,1,5
             or
                   set xtics offset 0,0.5 border -5,1,5
             Sets tics at the border, tics text with an offset of 0,0.5
             characters, and sets the start, increment, and end to -5,
             1, and 5, as requested.










   GNUPLOT 4.1                                                      246


             The [1mset grid [22moptions 'front', 'back' and 'layerdefault'
             affect the drawing order of the xtics, too.

             Examples:

             Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
                   set xtics 0,.5,10

             Make tics at ..., -10, -5, 0, 5, 10, ...
                   set xtics 5

             Make tics at 1, 100, 1e4, 1e6, 1e8.
                   set logscale x; set xtics 1,100,1e8

             The explicit ("<label>" <pos> <level>, ...) form allows
             arbitrary tic positions or non-numeric tic labels.  In
             this form, the tics do not need to be listed in numerical
             order.  Each tic has a position, optionally with a label.
             Note that the label is a string enclosed by quotes.  It
             may be a constant string, such as "hello", may contain
             formatting information for converting the position into
             its label, such as "%3f clients", or may be empty, "".
             See [1mset format [22mfor more information.  If no string is
             given, the default label (numerical) is used.

             An explicit tic mark has a third parameter, the "level".
             The default is level 0, a major tic.  A level of 1 gener-
             ates a minor tic.  If the level is specified, then the
             label must also be supplied.

             Examples:
                   set xtics ("low" 0, "medium" 50, "high" 100)
                   set xtics (1,2,4,8,16,32,64,128,256,512,1024)
                   set ytics ("bottom" 0, "" 10, "top" 20)
                   set ytics ("bottom" 0, "" 10 1, "top" 20)

             In the second example, all tics are labelled.  In the
             third, only the end tics are labelled.  In the fourth, the
             unlabeled tic is a minor tic.

             Normally if explicit tics are given, they are used instead
             of auto-generated tics. Conversely if you specify [1mset[0m
             [1mxtics auto [22mor the like it will erase any previously speci-
             fied explicit tics. You can mix explicit and auto- gener-
             ated tics by using the keyword [1madd[22m, which must appear
             before the tic style being added.

             Example:
                   set xtics 0,.5,10
                   set xtics add ("Pi" 3.14159)

             This will automatically generate tic marks every 0.5 along
             x, but will also add an explicit labeled tic mark at pi.










   GNUPLOT 4.1                                                      247


             However they are specified, tics will only be plotted when
             in range.

             Format (or omission) of the tic labels is controlled by
             [1mset format[22m, unless the explicit text of a label is
             included in the [1mset xtics ("<label>") [22mform.

             Minor (unlabelled) tics can be added automatically by the
             [1mset mxtics [22mcommand, or at explicit positions by the [1mset[0m
             [1mxtics ("" <pos> 1, ...) [22mform.




                  [1m84.96.1.  Xtics time_data[0m


                  In case of timeseries data, axis tic position values
                  must be given as quoted dates or times according to
                  the format [1mtimefmt[22m. If the <start>, <incr>, <end>
                  form is used, <start> and <end> must be given accord-
                  ing to [1mtimefmt[22m, but <incr> must be in seconds.  Times
                  will be written out according to the format given on
                  [1mset format[22m, however.

                  Examples:
                        set xdata time
                        set timefmt "%d/%m"
                        set xtics format "%b %d"
                        set xrange ["01/12":"06/12"]
                        set xtics "01/12", 172800, "05/12"

                        set xdata time
                        set timefmt "%d/%m"
                        set xtics format "%b %d"
                        set xrange ["01/12":"06/12"]
                        set xtics ("01/12", "" "03/12", "05/12")
                  Both of these will produce tics "Dec 1", "Dec 3", and
                  "Dec 5", but in the second example the tic at "Dec 3"
                  will be unlabelled.



                  [1m84.96.2.  Xtics rangelimited[0m


                  This option limits both the auto-generated axis tic
                  labels and the corresponding plot border to the range
                  of values actually present in the data that has been
                  plotted.  Note that this is independent of the cur-
                  rent range limits for the plot. For example, suppose
                  that the data in "file.dat" all lies in the range 2 <
                  y < 4.  Then the following commands will create a










   GNUPLOT 4.1                                                      248


                  plot for which the left-hand plot border (y axis) is
                  drawn for only this portion of the total y range, and
                  only the axis tics in this region are generated.
                  I.e., the plot will be scaled to the full range on y,
                  but there will be a gap between 0 and 2 on the left
                  border and another gap between 4 and 10. This style
                  is sometimes referred to as a [1mrange-frame [22mgraph.
                        set border 3
                        set yrange [0:10]
                        set ytics nomirror rangelimited
                        plot "file.dat"



             [1m84.97.  Xyplane[0m


             The [1mset xyplane [22mcommand adjusts the position at which the
             xy plane is drawn in a 3D plot.  The synonym "set tic-
             slevel" is accepted for backwards compatibility.

             Syntax:
                   set xyplane at <zvalue>
                   set xyplane relative <frac>
                   set ticslevel <frac>        # equivalent to set
             xyplane relative
                   show xyplane

             The form [1mset xyplane relative <frac> [22mplaces the xy plane
             below the range in Z, where the distance from the xy plane
             to Zmin is given as a fraction of the total range in z.
             The default value is 0.5.  Negative values are permitted,
             but tic labels on the three axes may overlap.  The older,
             deprecated, form [1mset ticslevel [22mis retained for backwards
             compatibility.

             To place the xy-plane at a position 'pos' on the z-axis,
             [1mticslevel [22mmay be set equal to  (pos - zmin) / (zmin -
             zmax).  However, this position will change if the z range
             is changed.

             The alternative form [1mset xyplane at <zvalue> [22mfixes the
             placement of the xy plane at a specific Z value regardless
             of the current z range. Thus to force the x, y, and z axes
             to meet at a common origin one would specify [1mset xyplane[0m
             [1mat 0[22m.

             See also [1mset view[22m, and [1mset zeroaxis[22m.















   GNUPLOT 4.1                                                      249


             [1m84.98.  Xzeroaxis[0m


             The [1mset xzeroaxis [22mcommand draws a line at y = 0.  For
             details, please see [1mset zeroaxis[22m.



             [1m84.99.  Y2data[0m


             The [1mset y2data [22mcommand sets y2 (right-hand) axis data to
             timeseries (dates/times).  Please see [1mset xdata[22m.



             [1m84.100.  Y2dtics[0m


             The [1mset y2dtics [22mcommand changes tics on the y2 (right-
             hand) axis to days of the week.  Please see [1mset xdtics [22mfor
             details.



             [1m84.101.  Y2label[0m


             The [1mset y2label [22mcommand sets the label for the y2 (right-
             hand) axis.  Please see [1mset xlabel[22m.



             [1m84.102.  Y2mtics[0m


             The [1mset y2mtics [22mcommand changes tics on the y2 (right-
             hand) axis to months of the year.  Please see [1mset xmtics[0m
             for details.



             [1m84.103.  Y2range[0m


             The [1mset y2range [22mcommand sets the vertical range that will
             be displayed on the y2 (right-hand) axis.  Please see [1mset[0m
             [1mxrange [22mfor details.















   GNUPLOT 4.1                                                      250


             [1m84.104.  Y2tics[0m


             The [1mset y2tics [22mcommand controls major (labelled) tics on
             the y2 (right-hand) axis.  Please see [1mset xtics [22mfor
             details.



             [1m84.105.  Y2zeroaxis[0m


             The [1mset y2zeroaxis [22mcommand draws a line at the origin of
             the y2 (right-hand) axis (x2 = 0).  For details, please
             see [1mset zeroaxis[22m.



             [1m84.106.  Ydata[0m


             The [1mset ydata [22mcommands sets y-axis data to timeseries
             (dates/times).  Please see [1mset xdata[22m.



             [1m84.107.  Ydtics[0m


             The [1mset ydtics [22mcommand changes tics on the y axis to days
             of the week.  Please see [1mset xdtics [22mfor details.



             [1m84.108.  Ylabel[0m


             This command sets the label for the y axis.  Please see
             [1mset xlabel[22m.



             [1m84.109.  Ymtics[0m


             The [1mset ymtics [22mcommand changes tics on the y axis to
             months of the year.  Please see [1mset xmtics [22mfor details.
















   GNUPLOT 4.1                                                      251


             [1m84.110.  Yrange[0m


             The [1mset yrange [22mcommand sets the vertical range that will
             be displayed on the y axis.  Please see [1mset xrange [22mfor
             details.



             [1m84.111.  Ytics[0m


             The [1mset ytics [22mcommand controls major (labelled) tics on
             the y axis.  Please see [1mset xtics [22mfor details.



             [1m84.112.  Yzeroaxis[0m


             The [1mset yzeroaxis [22mcommand draws a line at x = 0.  For
             details, please see [1mset zeroaxis[22m.



             [1m84.113.  Zdata[0m


             The [1mset zdata [22mcommand sets zaxis data to timeseries
             (dates/times).  Please see [1mset xdata[22m.



             [1m84.114.  Zdtics[0m


             The [1mset zdtics [22mcommand changes tics on the z axis to days
             of the week.  Please see [1mset xdtics [22mfor details.



             [1m84.115.  Zzeroaxis[0m


             The [1mset zzeroaxis [22mcommand draws a line through (x=0,y=0).
             This has no effect on 2D plots, including splot with [1mset[0m
             [1mview map[22m. For details, please see [1mset zeroaxis [22mand [1mset[0m
             [1mxyplane[22m.















   GNUPLOT 4.1                                                      252


             [1m84.116.  Cbdata[0m


             Set color box axis data to timeseries (dates/times).
             Please see [1mset xdata[22m.



             [1m84.117.  Cbdtics[0m


             The [1mset cbdtics [22mcommand changes tics on the color box axis
             to days of the week. Please see [1mset xdtics [22mfor details.



             [1m84.118.  Zero[0m


             The [1mzero [22mvalue is the default threshold for values
             approaching 0.0.

             Syntax:
                   set zero <expression>
                   show zero

             [1mgnuplot [22mwill not plot a point if its imaginary part is
             greater in magnitude than the [1mzero [22mthreshold.  This
             threshold is also used in various other parts of [1mgnuplot[0m
             as a (crude) numerical-error threshold.  The default [1mzero[0m
             value is 1e-8.  [1mzero [22mvalues larger than 1e-3 (the recipro-
             cal of the number of pixels in a typical bitmap display)
             should probably be avoided, but it is not unreasonable to
             set [1mzero [22mto 0.0.



             [1m84.119.  Zeroaxis[0m


             The x axis may be drawn by [1mset xzeroaxis [22mand removed by
             [1munset xzeroaxis[22m.  Similar commands behave similarly for
             the y, x2, y2, and z axes.

             Syntax:
                   set {x|x2|y|y2|z}zeroaxis { {linestyle | ls
             <line_style>}
                                              | { linetype | lt
             <line_type>}
                                                { linewidth | lw
             <line_width>}}
                   unset {x|x2|y|y2|z}zeroaxis
                   show {x|y|z}zeroaxis










   GNUPLOT 4.1                                                      253


             By default, these options are off.  The selected zero axis
             is drawn with a line of type <line_type> and width
             <line_width> (if supported by the terminal driver cur-
             rently in use), or a user-defined style <line_style>.

             If no linetype is specified, any zero axes selected will
             be drawn using the axis linetype (linetype 0).

             [1mset zeroaxis [22mis equivalent to [1mset xzeroaxis; set yze-[0m
             [1mroaxis[22m.  Note that the z-axis must be set separately using
             [1mset zzeroaxis[22m.

             Examples:

             To simply have the y=0 axis drawn visibly:

                    set xzeroaxis

             If you want a thick line in a different color or pattern,
             instead:

                    set xzeroaxis linetype 3 linewidth 2.5



             [1m84.120.  Zlabel[0m


             This command sets the label for the z axis.  Please see
             [1mset xlabel[22m.



             [1m84.121.  Zmtics[0m


             The [1mset zmtics [22mcommand changes tics on the z axis to
             months of the year.  Please see [1mset xmtics [22mfor details.



             [1m84.122.  Zrange[0m


             The [1mset zrange [22mcommand sets the range that will be dis-
             played on the z axis.  The zrange is used only by [1msplot[0m
             and is ignored by [1mplot[22m.  Please see [1mset xrange [22mfor
             details.















   GNUPLOT 4.1                                                      254


             [1m84.123.  Ztics[0m


             The [1mset ztics [22mcommand controls major (labelled) tics on
             the z axis.  Please see [1mset xtics [22mfor details.



             [1m84.124.  Cblabel[0m


             This command sets the label for the color box axis.
             Please see [1mset xlabel[22m.



             [1m84.125.  Cbmtics[0m


             The [1mset cbmtics [22mcommand changes tics on the color box axis
             to months of the year. Please see [1mset xmtics [22mfor details.



             [1m84.126.  Cbrange[0m


             The [1mset cbrange [22mcommand sets the range of values which are
             colored using the current [1mpalette [22mby styles [1mwith pm3d[22m,
             [1mwith image [22mand [1mwith palette[22m.  Values outside of the color
             range use color of the nearest extreme.

             If the cb-axis is autoscaled in [1msplot[22m, then the colorbox
             range is taken from [1mzrange[22m.  Points drawn in [1msplot ...[0m
             [1mpm3d|palette [22mcan be filtered by using different [1mzrange [22mand
             [1mcbrange[22m.

             Please see [1mset xrange [22mfor details on [1mset cbrange [22msyntax.
             See also [1mset palette [22mand [1mset colorbox[22m.



             [1m84.127.  Cbtics[0m


             The [1mset cbtics [22mcommand controls major (labelled) tics on
             the color box axis.  Please see [1mset xtics [22mfor details.
















   GNUPLOT 4.1                                                      255


        [1m85.  Shell[0m


        The [1mshell [22mcommand spawns an interactive shell.  To return to
        [1mgnuplot[22m, type [1mlogout [22mif using VMS, [1mexit [22mor the END-OF-FILE
        character if using Unix, or [1mexit [22mif using MS-DOS or OS/2.

        There are two ways of spawning a shell command: using [1msystem[0m
        command or via [1m! [22m($ if using VMS). The former command takes a
        string as a parameter and thus it can be used anywhere among
        other gnuplot commands, while the latter syntax requires to be
        the only command on the line. Control will return immediately
        to [1mgnuplot [22mafter this command is executed.  For example, in MS-
        DOS or OS/2,

              ! dir
        or
              system "dir"

        prints a directory listing and then returns to [1mgnuplot[22m.

        Other examples of the former syntax:
               system "date"; set time; plot "a.dat"
               print=1; if (print) replot; set out; system "lpr x.ps"



        [1m86.  Splot[0m


        [1msplot [22mis the command for drawing 3D plots (well, actually pro-
        jections on a 2D surface, but you knew that).  It can create a
        plot from functions or data read from files in a manner very
        similar to the [1mplot [22mcommand.  [1msplot [22mprovides only a single x,
        y, and z axis; there is no equivalent to the x2 and y2 sec-
        ondary axes provided by [1mplot[22m.

        See the [1mplot [22mcommand for many options available in both 2D and
        3D plots.

        Syntax:
              splot {<ranges>}
                    {<iteration>}
                    <function> | "<datafile>" {datafile-modifiers}}
                    {<title-spec>} {with <style>}
                    {, {definitions{,}} <function> ...}

        where either a <function> or the name of a data file enclosed
        in quotes is supplied.  The function can be a mathematical
        expression, or a triple of mathematical expressions in paramet-
        ric mode.

        By default [1msplot [22mdraws the xy plane completely below the










   GNUPLOT 4.1                                                      256


        plotted data.  The offset between the lowest ztic and the xy
        plane can be changed by [1mset xyplane[22m.  The orientation of a
        [1msplot [22mprojection is controlled by [1mset view[22m.  See [1mset view [22mand
        [1mset xyplane [22mfor more information.

        The syntax for setting ranges on the [1msplot [22mcommand is the same
        as for [1mplot[22m.  In non-parametric mode, the order in which ranges
        must be given is [1mxrange[22m, [1myrange[22m, and [1mzrange[22m.  In parametric
        mode, the order is [1murange[22m, [1mvrange[22m, [1mxrange[22m, [1myrange[22m, and [1mzrange[22m.

        The [1mtitle [22moption is the same as in [1mplot[22m.  The operation of [1mwith[0m
        is also the same as in [1mplot[22m, except that the plotting styles
        available to [1msplot [22mare limited to [1mlines[22m, [1mpoints[22m, [1mlinespoints[22m,
        [1mdots[22m, and [1mimpulses[22m;  the error-bar capabilities of [1mplot [22mare not
        available for [1msplot[22m.

        The [1mdatafile [22moptions have more differences.

        See also [1mshow plot[22m.




             [1m86.1.  Data-file[0m


             [1mSplot[22m, like [1mplot[22m, can display from a file.

             Syntax:
                   splot '<file_name>' {binary <binary list>}
                                       {{nonuniform} matrix}
                                       {index <index list>}
                                       {every <every list>}
                                       {using <using list>}

             The special filenames [1m"" [22mand [1m"-" [22mare permitted, as in
             [1mplot[22m.  See [1mspecial-filenames[22m.

             In brief, [1mbinary [22mand [1mmatrix [22mindicate that the data are in
             a special form, [1mindex [22mselects which data sets in a multi-
             data-set file are to be plotted, [1mevery [22mspecifies which
             datalines (subsets) within a single data set are to be
             plotted, and [1musing [22mdetermines how the columns within a
             single record are to be interpreted.

             The options [1mindex [22mand [1mevery [22mbehave the same way as with
             [1mplot[22m;  [1musing [22mdoes so also, except that the [1musing [22mlist must
             provide three entries instead of two.

             The [1mplot [22moptions [1mthru [22mand [1msmooth [22mare not available for
             [1msplot[22m, but [1mcntrparam [22mand [1mdgrid3d [22mprovide limited smoothing
             capabilities.











   GNUPLOT 4.1                                                      257


             Data file organization is essentially the same as for
             [1mplot[22m, except that each point is an (x,y,z) triple.  If
             only a single value is provided, it will be used for z,
             the datablock number will be used for y, and the index of
             the data point in the datablock will be used for x.  If
             two or four values are provided, [1mgnuplot [22muses the last
             value for calculating the color in pm3d plots.  Three val-
             ues are interpreted as an (x,y,z) triple.  Additional val-
             ues are generally used as errors, which can be used by
             [1mfit[22m.

             Single blank records separate datablocks in a [1msplot[0m
             datafile; [1msplot [22mtreats datablocks as the equivalent of
             function y-isolines.  No line will join points separated
             by a blank record.  If all datablocks contain the same
             number of points, [1mgnuplot [22mwill draw cross-isolines between
             datablocks, connecting corresponding points.  This is
             termed "grid data", and is required for drawing a surface,
             for contouring ([1mset contour[22m) and hidden-line removal ([1mset[0m
             [1mhidden3d[22m). See also [1msplot grid_data[22m.

             It is no longer necessary to specify [1mparametric [22mmode for
             three-column [1msplot[22ms.




                  [1m86.1.1.  Matrix[0m


                  Gnuplot can interpret matrix input in two different
                  ways.  The first of these assumes a uniform grid of x
                  and y coordinates, and assigns each value in the
                  input matrix to one element of this uniform grid.
                  This is the default for ascii data input, but not for
                  binary input.  Example commands for plotting uniform
                  matrix data:
                       splot 'file' matrix using 1:2:3          # ascii
                  input
                       splot 'file' binary general using 1:2:3  #
                  binary input

                  In a uniform grid matrix the z-values are read in a
                  row at a time, i. e.,
                      z11 z12 z13 z14 ...
                      z21 z22 z23 z24 ...
                      z31 z32 z33 z34 ...
                  and so forth.

                  For ascii input, a blank line or comment line ends
                  the matrix, and starts a new surface mesh.  You can
                  select among the meshes inside a file by the [1mindex[0m
                  option to the [1msplot [22mcommand, as usual.  The second










   GNUPLOT 4.1                                                      258


                  interpretation assumes a non-uniform grid with
                  explicit x and y coordinates. The first row of input
                  data contains the y coordinates; the first column of
                  input data contains the x coordinates.  For binary
                  input data, the first element of the first row must
                  contain the number of data columns. (This number is
                  ignored for ascii input).  Both the coordinates and
                  the data values in a binary input are treated as sin-
                  gle precision floats.  Example commands for plotting
                  non-uniform matrix data:
                       splot 'file' nonuniform matrix using 1:2:3  #
                  ascii input
                       splot 'file' binary matrix using 1:2:3      #
                  binary input

                  Thus the data organization for non-uniform matrix
                  input is

                        <N+1>  <y0>   <y1>   <y2>  ...  <yN>
                         <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
                         <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
                          :      :      :      :   ...    :

                  which is then converted into triplets:
                        <x0> <y0> <z0,0>
                        <x0> <y1> <z0,1>
                        <x0> <y2> <z0,2>
                         :    :     :
                        <x0> <yN> <z0,N>

                        <x1> <y0> <z1,0>
                        <x1> <y1> <z1,1>
                         :    :     :

                  These triplets are then converted into [1mgnuplot [22miso-
                  curves and then [1mgnuplot [22mproceeds in the usual manner
                  to do the rest of the plotting.

                  A collection of matrix and vector manipulation rou-
                  tines (in C) is provided in [1mbinary.c[22m.  The routine to
                  write binary data is

                        int
                  fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,col-
                  umn_title)

                  An example of using these routines is provided in the
                  file [1mbf_test.c[22m, which generates binary files for the
                  demo file [1mdemo/binary.dem[22m.

                  Usage in [1mplot[22m:
                      plot `a.dat` matrix
                      plot `a.dat` matrix using 1:3










   GNUPLOT 4.1                                                      259


                      plot 'a.gpbin' {matrix} binary using 1:3
                  will plot rows of the matrix, while using 2:3 will
                  plot matrix columns, and using 1:2 the point coordi-
                  nates (rather useless). Applying the [1mevery [22moption you
                  can specify explicit rows and columns.

                  Example -- rescale axes of a matrix in an ascii file:
                      splot `a.dat` matrix using (1+$1):(1+$2*10):3

                  Example -- plot the 3rd row of a matrix in an ascii
                  file:
                      plot 'a.dat' matrix using 1:3 every 1:999:1:2
                  (rows are enumerated from 0, thus 2 instead of 3).

                  Gnuplot can read matrix binary files by use of the
                  option [1mbinary [22mappearing without keyword qualifica-
                  tions unique to general binary, i.e., [1marray[22m, [1mrecord[22m,
                  [1mformat[22m, or [1mfiletype[22m.  Other general binary keywords
                  for translation should also apply to matrix binary.
                  (See [1mbinary general [22mfor more details.)



                  [1m86.1.2.  Example datafile[0m


                  A simple example of plotting a 3D data file is

                        splot 'datafile.dat'

                  where the file "datafile.dat" might contain:

                        # The valley of the Gnu.
                           0 0 10
                           0 1 10
                           0 2 10

                           1 0 10
                           1 1 5
                           1 2 10

                           2 0 10
                           2 1 1
                           2 2 10

                           3 0 10
                           3 1 0
                           3 2 10

                  Note that "datafile.dat" defines a 4 by 3 grid ( 4
                  rows of 3 points each ).  Rows (datablocks) are sepa-
                  rated by blank records.











   GNUPLOT 4.1                                                      260


                  Note also that the x value is held constant within
                  each dataline.  If you instead keep y constant, and
                  plot with hidden-line removal enabled, you will find
                  that the surface is drawn 'inside-out'.

                  Actually for grid data it is not necessary to keep
                  the x values constant within a datablock, nor is it
                  necessary to keep the same sequence of y values.
                  [1mgnuplot [22mrequires only that the number of points be
                  the same for each datablock.  However since the sur-
                  face mesh, from which contours are derived, connects
                  sequentially corresponding points, the effect of an
                  irregular grid on a surface plot is unpredictable and
                  should be examined on a case-by-case basis.



             [1m86.2.  Grid data[0m


             The 3D routines are designed for points in a grid format,
             with one sample, datapoint, at each mesh intersection; the
             datapoints may originate from either evaluating a func-
             tion, see [1mset isosamples[22m, or reading a datafile, see [1msplot[0m
             [1mdatafile[22m.  The term "isoline" is applied to the mesh lines
             for both functions and data.  Note that the mesh need not
             be rectangular in x and y, as it may be parameterized in u
             and v, see [1mset isosamples[22m.

             However, [1mgnuplot [22mdoes not require that format.  In the
             case of functions, 'samples' need not be equal to 'isosam-
             ples', i.e., not every x-isoline sample need intersect a
             y-isoline. In the case of data files, if there are an
             equal number of scattered data points in each datablock,
             then "isolines" will connect the points in a datablock,
             and "cross-isolines" will connect the corresponding points
             in each datablock to generate a "surface".  In either
             case, contour and hidden3d modes may give different plots
             than if the points were in the intended format.  Scattered
             data can be converted to a {different} grid format with
             [1mset dgrid3d[22m.

             The contour code tests for z intensity along a line
             between a point on a y-isoline and the corresponding point
             in the next y-isoline.  Thus a [1msplot [22mcontour of a surface
             with samples on the x-isolines that do not coincide with a
             y-isoline intersection will ignore such samples. Try:
                    set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
                    set style function lp
                    set contour
                    set isosamples 10,10; set samples 10,10;
                    splot cos(x)*cos(y)
                    set samples 4,10; replot










   GNUPLOT 4.1                                                      261


                    set samples 10,4; replot




             [1m86.3.  Splot surfaces[0m


             [1msplot [22mcan display a surface as a collection of points, or
             by connecting those points.  As with [1mplot[22m, the points may
             be read from a data file or result from evaluation of a
             function at specified intervals, see [1mset isosamples[22m.  The
             surface may be approximated by connecting the points with
             straight line segments, see [1mset surface[22m, in which case the
             surface can be made opaque with [1mset hidden3d.  [22mThe orien-
             tation from which the 3d surface is viewed can be changed
             with [1mset view[22m.

             Additionally, for points in a grid format, [1msplot [22mcan
             interpolate points having a common amplitude (see [1mset con-[0m
             [1mtour[22m) and can then connect those new points to display
             contour lines, either directly with straight-line segments
             or smoothed lines (see [1mset cntrparam[22m).  Functions are
             already evaluated in a grid format, determined by [1mset[0m
             [1misosamples [22mand [1mset samples[22m, while file data must either be
             in a grid format, as described in [1mdata-file[22m, or be used to
             generate a grid (see [1mset dgrid3d[22m).

             Contour lines may be displayed either on the surface or
             projected onto the base.  The base projections of the con-
             tour lines may be written to a file, and then read with
             [1mplot[22m, to take advantage of [1mplot[22m's additional formatting
             capabilities.



        [1m87.  Stats (Statistical Summary)[0m


        Syntax:
             stats 'filename' [using N[:M]] [name 'prefix'] [[no]out-
        put]]
        This command prepares a statistical summary of the data in one
        or two columns of a file. The using specifier is interpreted in
        the same way as for plot commands. See [1mplot [22mfor details on the
        [1mindex[22m, [1mevery[22m, and [1musing [22mdirectives. Data points are filtered
        against both xrange and yrange before analysis. See [1mset xrange[22m.
        The summary is printed to the screen by default.  Output can be
        redirected to a file by prior use of the command [1mset print[22m, or
        suppressed altogether using the [1mnooutput [22moption.

        In addition to printed output, the program stores the individ-
        ual statistics into three sets of variables.  The first set of










   GNUPLOT 4.1                                                      262


        variables reports how the data is laid out in the file:
             STATS_records           # total number of in-range data
        records
             STATS_outofrange        # number of records filtered out
        by range limits
             STATS_invalid           # number of invalid/incom-
        plete/missing records
             STATS_blank             # number of blank lines in the
        file
             STATS_blocks            # number of indexable data blocks
        in the file

        The second set reports properties of the in-range data from a
        single column.  If the corresponding axis is autoscaled (x-axis
        for the 1st column, y-axis for the optional second column) then
        no range limits are applied. If two columns are being analysed
        in a single [1mstats [22mcommand, the the suffix "_x" or "_y" is
        appended to each variable name.  I.e. STATS_min_x is the mini-
        mum value found in the first column, while STATS_min_y is the
        minimum value found in the second column.
             STATS_min               # minimum value of in-range data
        points
             STATS_max               # maximum value of in-range data
        points
             STATS_index_min         # index i for which data[i] ==
        STATS_min
             STATS_index_max         # index i for which data[i] ==
        STATS_max
             STATS_lo_quartile       # value of the lower (1st) quar-
        tile boundary
             STATS_median            # median value
             STATS_up_quartile       # value of the upper (3rd) quar-
        tile boundary
             STATS_mean              # mean value of in-range data
        points
             STATS_stddev            # standard deviation of the in-
        range data points
             STATS_sum               # sum
             STATS_sumsq             # sum of squares

        The third set of variables is only relevant to analysis of two
        data columns.
             STATS_correlation       # correlation coefficient between
        x and y values
             STATS_slope             # A corresponding to a linear fit
        y = Ax + B
             STATS_intercept         # B corresponding to a linear fit
        y = Ax + B
             STATS_sumxy             # sum of x*y
             STATS_pos_min_y         # x coordinate of a point with
        minimum y value
             STATS_pos_max_y         # x coordinate of a point with
        maximum y value










   GNUPLOT 4.1                                                      263


        It may be convenient to track the statistics from more than one
        file at the same time. The [1mname [22moption causes the default pre-
        fix "STATS" to be replaced by a user-specified string.  For
        example, the mean value of column 2 data from two different
        files could be compared by
             stats "file1.dat" using 2 name "A"
             stats "file2.dat" using 2 name "B"
             if (A_mean < B_mean) {...}

        The index reported in STATS_index_xxx corresponds to the value
        of pseudo-column 0 ($0) in plot commands.  I.e. the first point
        has index 0, the last point has index N-1.

        Data values are sorted to find the median and quartile bound-
        aries.  If the total number of points N is odd, then the median
        value is taken as the value of data point (N+1)/2. If N is
        even, then the median is reported as the mean value of points
        N/2 and (N+2)/2. Equivalent treatment is used for the quartile
        boundaries.

        For an example of using the [1mstats [22mcommand to help annotate a
        subsequent plot, see stats.dem.

        The current implementation does not allow analysis if either
        the X or Y axis is set to log-scaling.  This restriction may be
        removed in a later version.




        [1m88.  System[0m


        [1msystem "command" [22mexecutes "command" using the standard shell.
        See [1mshell[22m.  If called as a function, [1msystem("command") [22mreturns
        the resulting character stream from stdout as a string.  One
        optional trailing newline is ignored.

        This can be used to import external functions into gnuplot
        scripts:

              f(x) = real(system(sprintf("somecommand %f", x)))



        [1m89.  Test[0m


        This command graphically tests or presents terminal and palette
        capabilities.

        Syntax:
              test {terminal | palette [rgb|rbg|grb|gbr|brg|bgr]}










   GNUPLOT 4.1                                                      264


        [1mtest [22mor [1mtest terminal [22mcreates a display of line and point
        styles and other useful things appropriate for and supported by
        the [1mterminal [22myou are just using.

        [1mtest palette [22mplots profiles of R(z),G(z),B(z), where 0<=z<=1.
        These are the RGB components of the current color [1mpalette[22m. It
        also plots the apparent net intensity as calculated using NTSC
        coefficients to map RGB onto a grayscale.  The optional parame-
        ter, a permutation of letters rgb, determines the sequence in
        which the r,g,b profiles are drawn.



        [1m90.  Undefine[0m


        Clear one or more previously defined user variables.  This is
        useful in order to reset the state of a script containing an
        initialization test.

        A variable name can contain the wildcard character [1m* [22mas last
        character. If the wildcard character is found, all variables
        with names that begin with the prefix preceding the wildcard
        will be removed. This is useful to remove several variables
        sharing a common prefix. Note that the wildcard character is
        only allowed at the end of the variable name! Specifying the
        wildcard character as sole argument to [1mundefine [22mhas no effect.

        Example:

              undefine foo foo1 foo2
              if (!exists("foo")) load "initialize.gp"

              bar = 1; bar1 = 2; bar2 = 3
              undefine bar*                 # removes all three vari-
        ables




        [1m91.  Unset[0m


        Options set using the [1mset [22mcommand may be returned to their
        default state by the corresponding [1munset [22mcommand.  The [1munset[0m
        command may contain an optional iteration clause. See [1mitera-[0m
        [1mtion[22m.

        Examples:
              set xtics mirror rotate by -45 0,10,100
              ...
              unset xtics











   GNUPLOT 4.1                                                      265


              # Unset labels numbered between 100 and 200
              unset for [i=100:200] label i




             [1m91.1.  Terminal[0m


             The default terminal that is active at the time of program
             entry depends on the system platform, gnuplot build
             options, and the environmental variable GNUTERM.  Whatever
             this default may be, gnuplot saves it in the internal
             variable GNUTERM.  The [1munset terminal [22mcommand restores
             this initial state.  It is equivalent to [1mset terminal[0m
             [1mGNUTERM[22m.



        [1m92.  Update[0m


        This command writes the current values of the fit parameters
        into the given file, formatted as an initial-value file (as
        described in the [1mfit[22msection).  This is useful for saving the
        current values for later use or for restarting a converged or
        stopped fit.

        Syntax:
              update <filename> {<filename>}

        If a second filename is supplied, the updated values are writ-
        ten to this file, and the original parameter file is left
        unmodified.

        Otherwise, if the file already exists, [1mgnuplot [22mfirst renames it
        by appending [1m.old [22mand then opens a new file.  That is, "[1mupdate[0m
        [1m'fred'[22m" behaves the same as "[1m!rename fred fred.old; update[0m
        [1m'fred.old' 'fred'[22m".  [On DOS and other systems that use the
        twelve-character "filename.ext" naming convention, "ext" will
        be "[1mold[22m" and "filename" will be related (hopefully recogniz-
        ably) to the initial name.  Renaming is not done at all on VMS
        systems, since they use file-versioning.]

        Please see [1mfit [22mfor more information.



        [1m93.  While[0m


        Syntax:
              while (<expr>) {










   GNUPLOT 4.1                                                      266


                  <commands>
              }
        Execute a block of commands repeatedly so long as <expr> evalu-
        ates to a non-zero value.  This command cannot be mixed with
        old-style (un-bracketed) if/else statements.  See [1mif[22m.




        [1m94.  Terminal types[0m





        [1m95.  Complete list of terminals[0m


        Gnuplot supports a large number of output formats. These are
        selected by choosing an appropriate terminal type, possibly
        with additional modifying options. See [1mset terminal[22m.

        This document may describe terminal types that are not avail-
        able to you because they were not configured or installed on
        your system. To see a list of terminals available on a particu-
        lar gnuplot installation, type 'set terminal' with no modi-
        fiers.





             [1m95.1.  Aed767[0m


             The [1maed512 [22mand [1maed767 [22mterminal drivers support AED graph-
             ics terminals.  The two drivers differ only in their hori-
             zontal ranges, which are 512 and 768 pixels, respectively.
             Their vertical range is 575 pixels.  There are no options
             for these drivers.



             [1m95.2.  Aifm[0m



             [1mNOTE: Outdated terminal[22m, originally written for Adobe
             Illustrator 3.0+.  Since Adobe Illustrator understands
             PostScript level 1 commands directly, you should use [1mset[0m
             [1mterminal post level1 [22minstead.

             Syntax:










   GNUPLOT 4.1                                                      267


                   set terminal aifm {color|monochrome} {"<fontname>"}
             {<fontsize>}




             [1m95.3.  Aqua[0m


             This terminal relies on AquaTerm.app for display on Mac OS
             X.

             Syntax:
                   set terminal aqua {<n>} {title "<wintitle>"} {size
             <x> <y>}
                                     {font "<fontname>{,<fontsize>}"}
                                     {{no}enhanced} {solid|dashed} {dl
             <dashlength>}}

             where <n> is the number of the window to draw in (default
             is 0), <wintitle> is the name shown in the title bar
             (default "Figure <n>"), <x> <y> is the size of the plot
             (default is 846x594 pt = 11.75x8.25 in).

             Use <fontname> to specify the font (default is "Times-
             Roman"), and <fontsize> to specify the font size (default
             is 14.0 pt).

             The aqua terminal supports enhanced text mode (see
             [1menhanced[22m), except for overprint. Font support is limited
             to the fonts available on the system.  Character encoding
             can be selected by [1mset encoding [22mand currently supports
             iso_latin_1, iso_latin_2, cp1250, and UTF8 (default).

             Lines can be drawn either solid or dashed, (default is
             solid) and the dash spacing can be modified by <dash-
             length> which is a multiplier > 0.




             [1m95.4.  Be[0m


             The [1mbe [22mterminal type is present if gnuplot is built for
             the [1mbeos [22moperating system and for use with X servers.  It
             is selected at program startup if the [1mDISPLAY [22menvironment
             variable is set, if the [1mTERM [22menvironment variable is set
             to [1mxterm[22m, or if the [1m-display [22mcommand line option is used.

             Syntax:
                       set terminal be {reset} {<n>}











   GNUPLOT 4.1                                                      268


             Multiple plot windows are supported: [1mset terminal be <n>[0m
             directs the output to plot window number n.  If n>0, the
             terminal number will be appended to the window title and
             the icon will be labeled [1mgplt <n>[22m.  The active window may
             distinguished by a change in cursor (from default to
             crosshair.)

             Plot windows remain open even when the [1mgnuplot [22mdriver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing [1mclose [22mfrom a window manager
             menu.  All plot windows can be closed by specifying [1mreset[22m,
             which actually terminates the subprocess which maintains
             the windows (unless [1m-persist [22mwas specified).

             Plot windows will automatically be closed at the end of
             the session unless the [1m-persist [22moption was given.

             The size or aspect ratio of a plot may be changed by
             resizing the [1mgnuplot [22mwindow.

             Linewidths and pointsizes may be changed from within [1mgnu-[0m
             [1mplot [22mwith [1mset linestyle[22m.

             For terminal type [1mbe[22m, [1mgnuplot [22maccepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other [1mgnuplot [22moptions are available for the [1mbe[0m
             terminal.  These may be specified either as command-line
             options when [1mgnuplot [22mis invoked or as resources in the
             configuration file ".Xdefaults".  They are set upon ini-
             tialization and cannot be altered during a [1mgnuplot [22mses-
             sion.




                  [1m95.4.1.  Command-line_options[0m


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting [1mgnuplot [22mor as resources in your ".Xdefaults"
                  file:
















   GNUPLOT 4.1                                                      269


   +---------------------------------------------------------------------------------+
   |    `-mono`        forces monochrome rendering on color displays.                |
   |    `-gray`        requests grayscale rendering on grayscale or color displays.  |
   |                   (Grayscale displays receive monochrome rendering by default.) |
   |    `-clear`       requests that the window be cleared momentarily before a      |
   |                   new plot is displayed.                                        |
   |    `-raise`       raises plot window after each plot                            |
   |   `-noraise`      does not raise plot window after each plot                    |
   |   `-persist`      plots windows survive after main gnuplot program exits        |
   +---------------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.

   Example:
             gnuplot*gray: on

   [1mgnuplot [22malso provides a command line option ([1m-pointsize <v>[22m) and a
   resource, [1mgnuplot*pointsize: <v>[22m, to control the size of points
   plotted with the [1mpoints [22mplotting style.  The value [1mv [22mis a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, [1m-pointsize 2 [22muses points twice
   the default size, and [1m-pointsize 0.5 [22muses points half the normal
   size.



                  [1m95.4.2.  Monochrome_options[0m


                  For monochrome displays, [1mgnuplot [22mdoes not honor fore-
                  ground or background colors.  The default is black-
                  on-white.  [1m-rv [22mor [1mgnuplot*reverseVideo: on [22mrequests
                  white-on-black.




                  [1m95.4.3.  Color_resources[0m


                  For color displays, [1mgnuplot [22mhonors the following
                  resources (shown here with their default values) or
                  the greyscale resources.  The values may be color
                  names as listed in the BE rgb.txt file on your sys-
                  tem, hexadecimal RGB color specifications (see BE
                  documentation), or a color name followed by a comma
                  and an [1mintensity [22mvalue from 0 to 1.  For example,
                  [1mblue, 0.5 [22mmeans a half intensity blue.












   GNUPLOT 4.1                                                      270


                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is, for example,

   Example:
             gnuplot -background coral




                  [1m95.4.4.  Grayscale_resources[0m


                  When [1m-gray [22mis selected, [1mgnuplot [22mhonors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.



                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+














   GNUPLOT 4.1                                                      271


                  [1m95.4.5.  Line_resources[0m


                  [1mgnuplot [22mhonors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.



                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   [1mgnuplot [22mhonors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   [1mjk [22m([1mj [22mand [1mk [22mare >= 1  and <= 9) means a dashed line with a repeated
   pattern of [1mj [22mpixels on followed by [1mk [22mpixels off.  For example, '16'
   is a "dotted" line with one pixel on followed by six pixels off.
   More elaborate on/off patterns can be specified with a four-digit
   value.  For example, '4441' is four on, four off, four on, one off.
   The default values shown below are for monochrome displays or mono-
   chrome rendering on color or grayscale displays.  For color dis-
   plays, the default for each is 0 (solid line) except for [1maxisDashes[0m
   which defaults to a '16' dotted line.



                     +------------------------------+
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+











   GNUPLOT 4.1                                                      272


             [1m95.5.  Cairolatex[0m


             The [1mcairolatex [22mterminal device generates encapsulated
             PostScript (*.eps) or PDF output using the cairo and pango
             support libraries and uses LaTeX for text output using the
             same routines as the [1mepslatex [22mterminal.

             Syntax:
                   set terminal cairolatex
                                  {eps | pdf}
                                  {standalone | input}
                                  {blacktext | colortext | colourtext}
                                  {header <header> | noheader}
                                  {mono|color} {solid|dashed}
                                  {{no}transparent} {{no}crop} {back-
             ground <rgbcolor>}
                                  {font <font>} {fontscale <scale>}
                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             The cairolatex terminal prints a plot like [1mterminal[0m
             [1mepscairo [22mor [1mterminal pdfcairo [22mbut transfers the texts to
             LaTeX instead of including them in the graph. For refer-
             ence of options not explained here see [1mpdfcairo[22m.

             [1meps [22mand [1mpdf [22mselect the type of grahics output. Use [1meps[0m
             with latex/dvips and [1mpdf [22mfor pdflatex.

             [1mblacktext [22mforces all text to be written in black even in
             color mode;

             The [1mcairolatex [22mdriver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r,c), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.  See also the documentation for the [1mpslatex [22mter-
             minal driver.  To create multiline labels, use \short-
             stack, for example
                set ylabel '[r]{\shortstack{first line \\ second
             line}}'

             The [1mback [22moption of [1mset label [22mcommands is handled slightly
             different than in other terminals. Labels using 'back' are
             printed behind all other elements of the plot while labels
             using 'front' are printed above everything else.











   GNUPLOT 4.1                                                      273


             The driver produces two different files, one for the eps
             or pdf part of the figure and one for the LaTeX part. The
             name of the LaTeX file is taken from the [1mset output [22mcom-
             mand. The name of the eps/pdf file is derived by replacing
             the file extension (normally '.tex') with '.eps' or '.pdf'
             instead.  There is no LaTeX output if no output file is
             given!  Remember to close the [1moutput file [22mbefore next plot
             unless in [1mmultiplot [22mmode.

             In your LaTeX documents use '\input{filename}' to include
             the figure.  The '.eps' or '.pdf' file is included by the
             command \includegraphics{...}, so you must also include
             \usepackage{graphicx} in the LaTeX preamble.  If you want
             to use coloured text (option [1mcolourtext[22m) you also have to
             include \usepackage{color} in the LaTeX preamble.

             The behaviour concerning font selection depends on the
             header mode.  In all cases, the given font size is used
             for the calculation of proper spacing. When not using the
             [1mstandalone [22mmode the actual LaTeX font and font size at the
             point of inclusion is taken, so use LaTeX commands for
             changing fonts. If you use e.g. 12pt as font size for your
             LaTeX document, use '", 12"' as options. The font name is
             ignored. If using [1mstandalone [22mthe given font and font size
             are used, see below for a detailed description.

             If text is printed coloured is controlled by the TeX
             booleans \ifGPcolor and \ifGPblacktext. Only if \ifGPcolor
             is true and \ifGPblacktext is false, text is printed
             coloured. You may either change them in the generated TeX
             file or provide them globally in your TeX file, for exam-
             ple by using
                \newif\ifGPblacktext
                \GPblacktexttrue
             in the preamble of your document. The local assignment is
             only done if no global value is given.

             When using the cairolatex terminal give the name of the
             TeX file in the [1mset output [22mcommand including the file
             extension (normally ".tex").  The graph filename is gener-
             ated by replacing the extension.

             If using the [1mstandalone [22mmode a complete LaTeX header is
             added to the LaTeX file; and "-inc" is added to the file-
             name of the gaph file.  The [1mstandalone [22mmode generates a
             TeX file that produces output with the correct size when
             using dvips, pdfTeX, or VTeX.  The default, [1minput[22m, gener-
             ates a file that has to be included into a LaTeX document
             using the \input command.

             If a font other than "" or "default" is given it is inter-
             preted as LaTeX font name.  It contains up to three parts,
             separated by a comma: 'fontname,fontseries,fontshape'.  If










   GNUPLOT 4.1                                                      274


             the default fontshape or fontseries are requested, they
             can be omitted.  Thus, the real syntax for the fontname is
             '{fontname}{,fontseries}{,fontshape}'.  The naming conven-
             tion for all parts is given by the LaTeX font scheme.  The
             fontname is 3 to 4 characters long and is built as fol-
             lows: One character for the font vendor, two characters
             for the name of the font, and optionally one additional
             character for special fonts, e.g., 'j' for fonts with old-
             style numerals or 'x' for expert fonts. The names of many
             fonts is described in
                       http://www.tug.org/fontname/fontname.pdf
             For example, 'cmr' stands for Computer Modern Roman, 'ptm'
             for Times-Roman, and 'phv' for Helvetica.  The font series
             denotes the thickness of the glyphs, in most cases 'm' for
             normal ("medium") and 'bx' or 'b' for bold fonts.  The
             font shape is 'n' for upright, 'it' for italics, 'sl' for
             slanted, or 'sc' for small caps, in general.  Some fonts
             may provide different font series or shapes.

             Examples:

             Use Times-Roman boldface (with the same shape as in the
             surrounding text):
                   set terminal cairolatex font 'ptm,bx'
             Use Helvetica, boldface, italics:
                   set terminal cairolatex font 'phv,bx,it'
             Continue to use the surrounding font in slanted shape:
                   set terminal cairolatex font ',,sl'
             Use small capitals:
                   set terminal cairolatex font ',,sc'

             By this method, only text fonts are changed. If you also
             want to change the math fonts you have to use the "gnu-
             plot.cfg" file or the [1mheader [22moption, described below.

             In [1mstandalone [22mmode, the font size is taken from the given
             font size in the [1mset terminal [22mcommand. To be able to use a
             specified font size, a file "size<size>.clo" has to reside
             in the LaTeX search path.  By default, 10pt, 11pt, and
             12pt are supported.  If the package "extsizes" is
             installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.

             The [1mheader [22moption takes a string as argument.  This string
             is written into the generated LaTeX file.  If using the
             [1mstandalone [22mmode, it is written into the preamble, directly
             before the \begin{document} command.  In the [1minput [22mmode,
             it is placed directly after the \begingroup command to
             ensure that all settings are local to the plot.

             Examples:

             Use T1 fontencoding, change the text and math font to
             Times-Roman as well as the sans-serif font to Helvetica:










   GNUPLOT 4.1                                                      275


                 set terminal cairolatex standalone header \
                 "\\usepackage[T1]{fontenc}\n\\usepackage{math-
             ptmx}\n\\usepackage{helvet}"
             Use a boldface font in the plot, not influencing the text
             outside the plot:
                 set terminal cairolatex input header "\\bfseries"

             If the file "gnuplot.cfg" is found by LaTeX it is input in
             the preamble the LaTeX document, when using [1mstandalone[0m
             mode.  It can be used for further settings, e.g., changing
             the document font to Times-Roman, Helvetica, and Courier,
             including math fonts (handled by "mathptmx.sty"):
                   \usepackage{mathptmx}
                   \usepackage[scaled=0.92]{helvet}
                   \usepackage{courier}
             The file "gnuplot.cfg" is loaded before the header infor-
             mation given by the [1mheader [22mcommand.  Thus, you can use
             [1mheader [22mto overwrite some of settings performed using "gnu-
             plot.cfg"




             [1m95.6.  Canvas[0m



             The [1mcanvas [22mterminal creates a set of javascript commands
             that draw onto the HTML5 canvas element.  Syntax:
                   set terminal canvas {size <xsize>, <ysize>} {back-
             ground <rgb_color>}
                                       {font {<fontname>}{,<fontsize>}}
             | {fsize <fontsize>}
                                       {{no}enhanced} {linewidth <lw>}
                                       {rounded | butt}
                                       {solid | dashed {dashlength
             <dl>}}
                                       {standalone {mousing} | name
             '<funcname>'}
                                       {jsdir 'URL/for/javascripts'}
                                       {title '<some string>'}

             where <xsize> and <ysize> set the size of the plot area in
             pixels.  The default size in standalone mode is 600 by 400
             pixels.  The default font size is 10.

             NB: Only one font is available, the ascii portion of Her-
             shey simplex Roman provided in the file canvastext.js. You
             can replace this with the file canvasmath.js, which con-
             tains also UTF-8 encoded Hershey simplex Greek and math
             symbols. For consistency with other terminals, it is also
             possible to use [1mfont "name,size"[22m. Currently the font [1mname[0m
             is ignored, but browser support for named fonts is likely










   GNUPLOT 4.1                                                      276


             to arrive eventually.

             The default [1mstandalone [22mmode creates an html page contain-
             ing javascript code that renders the plot using the HTML 5
             canvas element.  The html page links to two required
             javascript files 'canvastext.js' and 'gnuplot_common.js'.
             An additional file 'gnuplot_dashedlines.js' is needed to
             support dashed lines.  By default these point to local
             files, on unix-like systems usually in directory
             /usr/local/share/gnuplot/<version>/js.  See installation
             notes for other platforms. You can change this by using
             the [1mjsdir [22moption to specify either a different local
             directory or a general URL.  The latter is usually appro-
             priate if the plot is exported for viewing on remote
             client machines.

             All plots produced by the canvas terminal are mouseable.
             The additional keyword [1mmousing [22mcauses the [1mstandalone [22mmode
             to add a mouse-tracking box underneath the plot. It also
             adds a link to a javascript file 'gnuplot_mouse.js' and to
             a stylesheet for the mouse box 'gnuplot_mouse.css' in the
             same local or URL directory as 'canvastext.js'.

             The [1mname [22moption creates a file containing only javascript.
             Both the javascript function it contains and the id of the
             canvas element that it draws onto are taken from the fol-
             lowing string parameter.  The commands
                   set term canvas name 'fishplot'
                   set output 'fishplot.js'
             will create a file containing a javascript function fish-
             plot() that will draw onto a canvas with id=fishplot.  An
             html page that invokes this javascript function must also
             load the canvastext.js function as described above.  A
             minimal html file to wrap the fishplot created above might
             be:

                   <html>
                   <head>
                       <script src="canvastext.js"></script>
                       <script src="gnuplot_common.js"></script>
                   </head>
                   <body onload="fishplot();">
                       <script src="fishplot.js"></script>
                       <canvas id="fishplot" width=600 height=400>
                           <div id="err_msg">No support for HTML 5 can-
             vas element</div>
                       </canvas>
                   </body>
                   </html>

             The individual plots drawn on this canvas will have names
             fishplot_plot_1, fishplot_plot_2, and so on. These can be
             referenced by external javascript routines, for example










   GNUPLOT 4.1                                                      277


             gnuplot.toggle_visibility("fishplot_plot_2").




             [1m95.7.  Cgi[0m


             The [1mcgi [22mand [1mhcgi [22mterminal drivers support SCO CGI drivers.
             [1mhcgi [22mis for printers; the environment variable CGIPRNT
             must be set.  [1mcgi [22mmay be used for either a display or
             hardcopy; the environment variable CGIDISP is checked,
             first, then CGIPRNT.  These terminals have no options.



             [1m95.8.  Cgm[0m


             The [1mcgm [22mterminal generates a Computer Graphics Metafile,
             Version 1.  This file format is a subset of the ANSI
             X3.122-1986 standard entitled "Computer Graphics -
             Metafile for the Storage and Transfer of Picture Descrip-
             tion Information".

             Syntax:
                   set terminal cgm {color | monochrome} {solid |
             dashed} {{no}rotate}
                                    {<mode>} {width <plot_width>}
             {linewidth <line_width>}
                                    {font "<fontname>,<fontsize>"}
                                    {background <rgb_color>}
               [deprecated]         {<color0> <color1> <color2> ...}

             [1msolid [22mdraws all curves with solid lines, overriding any
             dashed patterns; <mode> is [1mlandscape[22m, [1mportrait[22m, or
             [1mdefault[22m; <plot_width> is the assumed width of the plot in
             points; <line_width> is the line width in points (default
             1); <fontname> is the name of a font (see list of fonts
             below) <fontsize> is the size of the font in points
             (default 12).

             The first six options can be in any order.  Selecting
             [1mdefault [22msets all options to their default values.

             The mechanism of setting line colors in the [1mset term [22mcom-
             mand is deprecated.  Instead you should set the background
             using a separate keyword and set the line colors using [1mset[0m
             [1mlinetype[22m.  The deprecated mechanism accepted colors of the
             form 'xrrggbb', where x is the literal character 'x' and
             'rrggbb' are the red, green and blue components in hex.
             The first color was used for the background, subsequent
             colors are assigned to successive line types.










   GNUPLOT 4.1                                                      278


             Examples:
                   set terminal cgm landscape color rotate dashed width
             432 \
                                  linewidth 1  'Helvetica Bold' 12
             # defaults
                   set terminal cgm linewidth 2  14  # wider lines &
             larger font
                   set terminal cgm portrait "Times Italic" 12
                   set terminal cgm color solid      # no pesky dashes!




                  [1m95.8.1.  Cgm font[0m


                  The first part of a Computer Graphics Metafile, the
                  metafile description, includes a font table.  In the
                  picture body, a font is designated by an index into
                  this table.  By default, this terminal generates a
                  table with the following 35 fonts, plus six more with
                  [1mitalic [22mreplaced by [1moblique[22m, or vice-versa (since at
                  least the Microsoft Office and Corel Draw CGM import
                  filters treat [1mitalic [22mand [1moblique [22mas equivalent):







































   GNUPLOT 4.1                                                      279


                   +-----------------------------------+
                   |        CGM fonts                  |
                   +-----------------------------------+
                   |        Helvetica                  |
                   |        Helvetica Bold             |
                   |        Helvetica Oblique          |
                   |        Helvetica Bold Oblique     |
                   |        Times Roman                |
                   |        Times Bold                 |
                   |        Times Italic               |
                   |        Times Bold Italic          |
                   |        Courier                    |
                   |        Courier Bold               |
                   |        Courier Oblique            |
                   |        Courier Bold Oblique       |
                   |        Symbol                     |
                   |        Hershey/Cartographic_Roman |
                   |        Hershey/Cartographic_Greek |
                   |        Hershey/Simplex_Roman      |
                   |        Hershey/Simplex_Greek      |
                   |        Hershey/Simplex_Script     |
                   |        Hershey/Complex_Roman      |
                   |        Hershey/Complex_Greek      |
                   |        Hershey/Complex_Script     |
                   |        Hershey/Complex_Italic     |
                   |        Hershey/Complex_Cyrillic   |
                   |        Hershey/Duplex_Roman       |
                   |        Hershey/Triplex_Roman      |
                   |        Hershey/Triplex_Italic     |
                   |        Hershey/Gothic_German      |
                   |        Hershey/Gothic_English     |
                   |        Hershey/Gothic_Italian     |
                   |        Hershey/Symbol_Set_1       |
                   |        Hershey/Symbol_Set_2       |
                   |        Hershey/Symbol_Math        |
                   |        ZapfDingbats               |
                   |        Script                     |
                   |        15                         |
                   +-----------------------------------+


   The first thirteen of these fonts are required for WebCGM.  The
   Microsoft Office CGM import filter implements the 13 standard fonts
   listed above, and also 'ZapfDingbats' and 'Script'.  However, the
   script font may only be accessed under the name '15'.  For more on
   Microsoft import filter font substitutions, check its help file
   which you may find here:
     C:\Program Files\Microsoft Office\Office\Cgmimp32.hlp
   and/or its configuration file, which you may find here:
     C:\Program Files\Common Files\Microsoft
   Shared\Grphflt\Cgmimp32.cfg

   In the [1mset term [22mcommand, you may specify a font name which does not










   GNUPLOT 4.1                                                      280


   appear in the default font table.  In that case, a new font table is
   constructed with the specified font as its first entry. You must
   ensure that the spelling, capitalization, and spacing of the name
   are appropriate for the application that will read the CGM file.
   (Gnuplot and any MIL-D-28003A compliant application ignore case in
   font names.)  If you need to add several new fonts, use several [1mset[0m
   [1mterm [22mcommands.

   Example:
         set terminal cgm 'Old English'
         set terminal cgm 'Tengwar'
         set terminal cgm 'Arabic'
         set output 'myfile.cgm'
         plot ...
         set output

   You cannot introduce a new font in a [1mset label [22mcommand.



                  [1m95.8.2.  Cgm fontsize[0m


                  Fonts are scaled assuming the page is 6 inches wide.
                  If the [1msize [22mcommand is used to change the aspect
                  ratio of the page or the CGM file is converted to a
                  different width, the resulting font sizes will be
                  scaled up or down accordingly.  To change the assumed
                  width, use the [1mwidth [22moption.



                  [1m95.8.3.  Cgm linewidth[0m


                  The [1mlinewidth [22moption sets the width of lines in pt.
                  The default width is 1 pt.  Scaling is affected by
                  the actual width of the page, as discussed under the
                  [1mfontsize [22mand [1mwidth [22moptions.



                  [1m95.8.4.  Cgm rotate[0m


                  The [1mnorotate [22moption may be used to disable text rota-
                  tion.  For example, the CGM input filter for Word for
                  Windows 6.0c can accept rotated text, but the DRAW
                  editor within Word cannot.  If you edit a graph (for
                  example, to label a curve), all rotated text is
                  restored to horizontal.  The Y axis label will then
                  extend beyond the clip boundary.  With [1mnorotate[22m, the
                  Y axis label starts in a less attractive location,










   GNUPLOT 4.1                                                      281


                  but the page can be edited without damage.  The
                  [1mrotate [22moption confirms the default behavior.



                  [1m95.8.5.  Cgm solid[0m


                  The [1msolid [22moption may be used to disable dashed line
                  styles in the plots.  This is useful when color is
                  enabled and the dashing of the lines detracts from
                  the appearance of the plot. The [1mdashed [22moption con-
                  firms the default behavior, which gives a different
                  dash pattern to each line type.



                  [1m95.8.6.  Cgm size[0m


                  Default size of a CGM plot is 32599 units wide and
                  23457 units high for landscape, or 23457 units wide
                  by 32599 units high for portrait.



                  [1m95.8.7.  Cgm width[0m


                  All distances in the CGM file are in abstract units.
                  The application that reads the file determines the
                  size of the final plot.  By default, the width of the
                  final plot is assumed to be 6 inches (15.24 cm).
                  This distance is used to calculate the correct font
                  size, and may be changed with the [1mwidth [22moption.  The
                  keyword should be followed by the width in points.
                  (Here, a point is 1/72 inch, as in PostScript.  This
                  unit is known as a "big point" in TeX.)  Gnuplot
                  [1mexpressions [22mcan be used to convert from other units.

                  Example:
                        set terminal cgm width 432            # default
                        set terminal cgm width 6*72           # same as
                  above
                        set terminal cgm width 10/2.54*72     # 10 cm
                  wide



                  [1m95.8.8.  Cgm nofontlist[0m













   GNUPLOT 4.1                                                      282


                  The default font table includes the fonts recommended
                  for WebCGM, which are compatible with the Computer
                  Graphics Metafile input filter for Microsoft Office
                  and Corel Draw.  Another application might use dif-
                  ferent fonts and/or different font names, which may
                  not be documented.  The [1mnofontlist [22m(synonym [1mwinword6[22m)
                  option deletes the font table from the CGM file.  In
                  this case, the reading application should use a
                  default table.  Gnuplot will still use its own
                  default font table to select font indices.  Thus,
                  'Helvetica' will give you an index of 1, which should
                  get you the first entry in your application's default
                  font table. 'Helvetica Bold' will give you its second
                  entry, etc.




             [1m95.9.  Context[0m


             ConTeXt is a macro package for TeX, highly integrated with
             Metapost (for drawing figures) and intended for creation
             of high-quality PDF documents.  The terminal outputs Meta-
             fun source, which can be edited manually, but you should
             be able to configure most things from outside.

             For an average user of ConTeXt + gnuplot module it's rec-
             ommended to refer to [1mUsing ConTeXt [22mrather than reading
             this page or to read the manual of the gnuplot module for
             ConTeXt.

             The [1mcontext [22mterminal supports the following options:

             Syntax:
                  set term context {default}
                          {defaultsize | size <scale> | size
             <xsize>{in|cm}, <ysize>{in|cm}}
                          {input | standalone}
                          {timestamp | notimestamp}
                          {noheader | header "<header>"}
                          {color | colour | monochrome}
                          {rounded | mitered | beveled} {round | butt |
             squared}
                          {dashed | solid} {dashlength | dl <dl>}
                          {linewidth | lw <lw>}
                          {fontscale <fontscale>}
                          {mppoints | texpoints}
                          {inlineimages | externalimages}
                          {defaultfont | font "{<fontname>}{,<font-
             size>}"}

             In non-standalone ([1minput[22m) graphic only parameters [1msize [22mto










   GNUPLOT 4.1                                                      283


             select graphic size, [1mfontscale [22mto scale all the labels for
             a factor <fontscale> and font size, make sense, the rest
             is silently ignored and should be configured in the .tex
             file which inputs the graphic.  It's highly recommended to
             set the proper fontsize if document font differs from
             12pt, so that gnuplot will know how much space to reserve
             for labels.

             [1mdefault [22mresets all the options to their default values.

             [1mdefaultsize [22msets the plot size to 5in,3in.  [1msize [22m<scale>
             sets the plot size to <scale> times <default value>.  If
             two arguments are given (separated with ','), the first
             one sets the horizontal size and the second one the verti-
             cal size.  Size may be given without units (in which case
             it means relative to the default value), with inches
             ('in') or centimeters ('cm').

             [1minput [22m(default) creates a graphic that can be included
             into another ConTeXt document.  [1mstandalone [22madds some
             lines, so that the document might be compiled as-is.  You
             might also want to add [1mheader [22min that case.

             Use [1mheader [22mfor any additional settings/definitions/macros
             that you might want to include in a standalone graphic.
             [1mnoheader [22mis the default.

             [1mnotimestamp [22mprevents printing creation time in comments
             (if version control is used, one may prefer not to commit
             new version when only date changes).

             [1mcolor [22mto make color plots is the default, but [1mmonochrome[0m
             doesn't do anything special yet.  If you have any good
             ideas how the behaviour should differ to suit the mono-
             chrome printers better, your suggestions are welcome.

             [1mrounded [22m(default), [1mmitered [22mand [1mbeveled [22mcontrol the shape
             of line joins.  [1mround [22m(default), [1mbutt [22mand [1msquared [22mcontrol
             the shape of line caps.  See PostScript or PDF Reference
             Manual for explanation. For wild-behaving functions and
             thick lines it is better to use [1mrounded [22mand [1mround [22mto pre-
             vent sharp corners in line joins.  (Some general support
             for this should be added to Gnuplot, so that the same
             options could be set for each line (style) separately).

             [1mdashed [22m(default) uses different dash patterns for differ-
             ent line types, [1msolid [22mdraws all plots with solid lines.

             [1mdashlength [22mor [1mdl [22mscales the length of the dashed-line seg-
             ments by <dl>.  [1mlinewidth [22mor [1mlw [22mscales all linewidths by
             <lw>.  (lw 1 stands for 0.5bp, which is the default line
             width when drawing with Metapost.)  [1mfontscale [22mscales text
             labels for factor <fontscale> relative to default document










   GNUPLOT 4.1                                                      284


             font.

             [1mmppoints [22muses predefined point shapes, drawn in Metapost.
             [1mtexpoints [22muses easily configurable set of symbols, defined
             with ConTeXt in the following way:
                  \defineconversion[my own points][+,{\ss x},\mathemat-
             ics{\circ}]
                  \setupGNUPLOTterminal[context][points=tex,pointset=my
             own points]

             [1minlineimages [22mwrites binary images to a string and only
             works in ConTeXt MKIV.  [1mexternalimages [22mwrites PNG files to
             disk and also works with ConTeXt MKII.  Gnuplot needs to
             have support for PNG images built in for this to work.

             With [1mfont [22myou can set font name and size in standalone
             graphics.  In non-standalone ([1minput[22m) mode only the font
             size is important to reserve enough space for text labels.
             The command
                  set term context font "myfont,ss,10"
             will result in
                  \setupbodyfont[myfont,ss,10pt]
             If you additionaly set [1mfontscale [22mto 0.8 for example, then
             the resulting font will be 8pt big and
                  set label ... font "myfont,12"
             will come out as 9.6pt.

             It is your own responsibility to provide proper type-
             scripts (and header), otherwise switching the font will
             have no effect.  For a standard font in ConTeXt MKII (pdf-
             TeX) you could use:
                  set terminal context standalone header '\usetype-
             script[iwona][ec]' \
                      font "iwona,ss,11"
             Please take a look into ConTeXt documentation, wiki or
             mailing list (archives) for any up-to-date information
             about font usage.

             Examples:
                  set terminal context size 10cm, 5cm     # 10cm, 5cm
                  set terminal context size 4in, 3in      # 4in, 3in
             For standalone (whole-page) plots with labels in UTF-8
             encoding:
                  set terminal context standalone header
             '\enableregime[utf-8]'


















   GNUPLOT 4.1                                                      285


                  [1m95.9.1.  Requirements[0m


                  You need gnuplot module for ConTeXt
                       http://ctan.org/pkg/context-gnuplot
                  and a recent version of ConTeXt.  If you want to call
                  gnuplot on-the-fly, you also need write18 enabled.
                  In most TeX distributions this can be set with
                  shell_escape=t in texmf.cnf.

                  See
                            http://wiki.contextgarden.net/Gnuplot
                  for details about this terminal and for more exhaus-
                  tive help & examples.




                  [1m95.9.2.  Calling gnuplot from ConTeXt[0m


                  The easiest way to make plots in ConTeXt documents is
                       \usemodule[gnuplot]
                       \starttext
                       \title{How to draw nice plots with {\sc gnu-
                  plot}?}
                       \startGNUPLOTscript[sin]
                       set format y "%.1f"
                       plot sin(x) t '$\sin(x)$'
                       \stopGNUPLOTscript
                       \useGNUPLOTgraphic[sin]
                       \stoptext
                  This will run gnuplot automatically and include the
                  resulting figure in the document.



             [1m95.10.  Corel[0m


             The [1mcorel [22mterminal driver supports CorelDraw.

             Syntax:
                   set terminal corel {  default
                                       | {monochrome | color
                                            {"<font>" {<fontsize>
                                               {<xsize> <ysize>
             {<linewidth> }}}}}

             where the fontsize and linewidth are specified in points
             and the sizes in inches.  The defaults are monochrome,
             "SwitzerlandLight", 22, 8.2, 10 and 1.2.











   GNUPLOT 4.1                                                      286


             [1m95.11.  Debug[0m


             This terminal is provided to allow for the debugging of
             [1mgnuplot[22m.  It is likely to be of use only for users who are
             modifying the source code.



             [1m95.12.  Dumb[0m


             The [1mdumb [22mterminal driver plots into a text block using
             ascii characters.  It has an optional size specification
             and a trailing linefeed flag.

             Syntax:
                   set terminal dumb {size <xchars>,<ychars>}
             {[no]feed}
                                     {[no]enhanced}

             where <xchars> and <ychars> set the size of the text
             block. The default is 79 by 24. The last newline is
             printed only if [1mfeed [22mis enabled.

             Example:
                   set term dumb size 60,15
                   plot [-5:6.5] sin(x) with impulse

                        1
             +-------------------------------------------------+
                      0.8 +|||++                   ++||||++   sin(x)
             +----+ |
                      0.6 +|||||+                 ++|||||||+
             |
                      0.4 +||||||+               ++|||||||||+
             |
                      0.2 +|||||||+             ++|||||||||||+
             +|
                        0
             ++++++++++++++++++++++++++++++++++++++++++++++++++|
                     -0.2 +        +|||||||||||+
             +|||||||||||+ |
                     -0.4 +         +|||||||||+
             +|||||||||+  |
                     -0.6 +          +|||||||+
             +|||||||+   |
                     -0.8 +   +       ++||||+   +       +
             ++||||+  + |
                       -1
             +---+--------+--------+-------+--------+--------+-+
                             -4       -2        0       2        4
             6










   GNUPLOT 4.1                                                      287


             [1m95.13.  Dxf[0m


             The [1mdxf [22mterminal driver creates pictures that can be
             imported into AutoCad (Release 10.x).  It has no options
             of its own, but some features of its plots may be modified
             by other means.  The default size is 120x80 AutoCad units,
             which can be changed by [1mset size[22m.  [1mdxf [22muses seven colors
             (white, red, yellow, green, cyan, blue and magenta), which
             can be changed only by modifying the source file.  If a
             black-and-white plotting device is used, the colors are
             mapped to differing line thicknesses.  See the description
             of the AutoCad print/plot command.



             [1m95.14.  Dxy800a[0m


             This terminal driver supports the Roland DXY800A plotter.
             It has no options.



             [1m95.15.  Eepic[0m


             The [1meepic [22mterminal driver supports the extended LaTeX pic-
             ture environment.  It is an alternative to the [1mlatex[0m
             driver.

             The output of this terminal is intended for use with the
             "eepic.sty" macro package for LaTeX.  To use it, you need
             "eepic.sty", "epic.sty" and a printer driver that supports
             the "tpic" \specials.  If your printer driver doesn't sup-
             port those \specials, "eepicemu.sty" will enable you to
             use some of them.  dvips and dvipdfm do support the "tpic"
             \specials.

             Syntax:
                set terminal eepic {default} {color|dashed} {rotate}
             {size XX,YY}
                                   {small|tiny|<fontsize>}

             Options: You can give options in any order you wish.
             'color' causes gnuplot to produce \color{...} commands so
             that the graphs are colored. Using this option, you must
             include \usepackage{color} in the preambel of your latex
             document.  'dashed' will allow dashed line types; without
             this option, only solid lines with varying thickness will
             be used.  'dashed' and 'color' are mutually exclusive; if
             'color' is specified, then 'dashed' will be ignored.
             'rotate' will enable true rotated text (by 90 degrees).










   GNUPLOT 4.1                                                      288


             Otherwise, rotated text will be typeset with letters
             stacked above each other. If you use this option you must
             include \usepackage{graphicx} in the preamble.  'small'
             will use \scriptsize symbols as point markers (Probably
             does not work with TeX, only LaTeX2e). Default is to use
             the default math size.  'tiny' uses \scriptscriptstyle
             symbols.  'default' resets all options to their defaults =
             no color, no dashed lines, pseudo-rotated (stacked) text,
             large point symbols.  <fontsize> is a number which speci-
             fies the font size inside the picture environment; the
             unit is pt (points), i.e., 10 pt equals approx. 3.5 mm.
             If fontsize is not specified, then all text inside the
             picture will be set in \footnotesize.

             Notes: Remember to escape the # character (or other chars
             meaningful to (La-)TeX) by \\ (2 backslashes).  It seems
             that dashed lines become solid lines when the vertices of
             a plot are too close. (I do not know if that is a general
             problem with the tpic specials, or if it is caused by a
             bug in eepic.sty or dvips/dvipdfm.)  The default size of
             an eepic plot is 5x3 inches. You can change this using the
             [1msize [22mterminal option.  Points, among other things, are
             drawn using the LaTeX commands "\Diamond", "\Box", etc.
             These commands no longer belong to the LaTeX2e core; they
             are included in the latexsym package, which is part of the
             base distribution and thus part of any LaTeX implementa-
             tion. Please do not forget to use this package.  Instead
             of latexsym, you can also include the amssymb package.
             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to
             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Examples: set term eepic
               output graphs as eepic macros inside a picture environ-
             ment;
               \input the resulting file in your LaTeX document.
             set term eepic color tiny rotate 8
               eepic macros with \color macros, \scripscriptsize point
             markers,
               true rotated text, and all text set with 8pt.

             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):










   GNUPLOT 4.1                                                      289


                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             [1m95.16.  Emf[0m


             The [1memf [22mterminal generates an Enhanced Metafile Format
             file.  This file format is recognized by many Windows
             applications.

             Syntax:
                   set terminal emf {color | monochrome} {solid |
             dashed}
                                    {enhanced {noproportional}}
                                    {rounded | butt}
                                    {linewidth <LW>} {dashlength <DL>}
                                    {size XX,YY} {background
             <rgb_color>}
                                    {font "<fontname>{,<fontsize>}"}
                                    {fontscale <scale>}

             In [1mmonochrome [22mmode successive line types cycle through
             dash patterns.  In [1mcolor [22mmode successive line types use
             successive colors, and only after all 8 default colors are
             exhausted is the dash pattern incremented.  [1msolid [22mdraws
             all curves with solid lines, overriding any dashed pat-
             terns; [1mlinewidth <factor> [22mmultiplies all line widths by
             this factor.  [1mdashlength <factor> [22mis useful for thick
             lines.  <fontname> is the name of a font; and [1m<fontsize>[0m
             is the size of the font in points.

             The nominal size of the output image defaults to 1024x768
             in arbitrary units. You may specify a different nominal
             size using the [1msize [22moption.

             Enhanced text mode tries to approximate proportional char-
             acter spacing.  If you are using a monospaced font, or
             don't like the approximation, you can turn off this cor-
             rection using the [1mnoproportional [22moption.

             The default settings are [1mcolor solid font "Arial,12" size[0m
             [1m1024,768 [22mSelecting [1mdefault [22msets all options to their
             default values.

             Examples:
                   set terminal emf 'Times Roman Italic, 12'
                   set terminal emf dashed    # otherwise all lines are
             solid











   GNUPLOT 4.1                                                      290


             [1m95.17.  Emxvga[0m


             The [1memxvga[22m, [1memxvesa [22mand [1mvgal [22mterminal drivers support PCs
             with SVGA, vesa SVGA and VGA graphics boards, respec-
             tively.  They are intended to be compiled with "emx-gcc"
             under either DOS or OS/2.  They also need VESA and SVGAKIT
             maintained by Johannes Martin (JMARTIN@GOOFY.ZDV.UNI-
             MAINZ.DE) with additions by David J. Liu
             (liu@phri.nyu.edu).

             Syntax:
                   set terminal emxvga
                   set terminal emxvesa {vesa-mode}
                   set terminal vgal

             The only option is the vesa mode for [1memxvesa[22m, which
             defaults to G640x480x256.



             [1m95.18.  Epscairo[0m


             The [1mepscairo [22mterminal device generates encapsulated Post-
             Script (*.eps) using the cairo and pango support
             libraries.  cairo verion >= 1.6 is required.

             Please read the help for the [1mpdfcairo [22mterminal.



             [1m95.19.  Epslatex[0m


             The [1mepslatex [22mdriver generates output for further process-
             ing by LaTeX.

             Syntax:
                   set terminal epslatex   {default}
                   set terminal epslatex   {standalone | input}
                                           {oldstyle | newstyle}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}
                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam










   GNUPLOT 4.1                                                      291


             <samples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {header <header> | noheader}
                                           {blacktext | colortext |
             colourtext}
                                           {{font} "fontname{,font-
             size}" {<fontsize>}}
                                           {fontscale <scale>}

             The epslatex terminal prints a plot as [1mterminal postscript[0m
             [1meps [22mbut transfers the texts to LaTeX instead of including
             in the PostScript code. Thus, many options are the same as
             in the [1mpostscript terminal[22m.

             The appearance of the epslatex terminal changed between
             versions 4.0 and 4.2 to reach better consistency with the
             postscript terminal: The plot size has been changed from 5
             x 3 inches to 5 x 3.5 inches; the character width is now
             estimated to be 60% of the font size while the old epsla-
             tex terminal used 50%;  now, the larger number of post-
             script linetypes and symbols are used.  To reach an
             appearance that is nearly identical to the old one specify
             the option [1moldstyle[22m. (In fact some small differences
             remain: the symbol sizes are slightly different, the tics
             are half as large as in the old terminal which can be
             changed using [1mset tics scale[22m, and the arrows have all fea-
             tures as in the postscript terminal.)

             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in [1mpostscript pro-[0m
             [1mlogue[22m.

             The option [1mcolor [22menables color, while [1mmonochrome [22mprefers
             black and white drawing elements. Further, [1mmonochrome [22muses
             gray [1mpalette [22mbut it does not change color of objects spec-
             ified with an explicit [1mcolorspec[22m.  [1msolid [22mdraws all plots
             with solid lines, overriding any dashed patterns.  [1mdash-[0m
             [1mlength [22mor [1mdl [22mscales the length of the dashed-line segments
             by <DL>, which is a floating-point number greater than
             zero.  [1mlinewidth [22mor [1mlw [22mscales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The [1mlevel1 [22moption sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag [1mlevel1 [22mcan be toggled later by










   GNUPLOT 4.1                                                      292


             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.

             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.

             [1mclip [22mtells PostScript to clip all output to the bounding
             box; [1mnoclip [22mis the default.

             [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via [1mset palette functions[22m) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             [1msize [22moption changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the [1msize [22moption.  NB: [1mthis is a change from the previ-[0m
             [1mously recommended method of using the set size command[0m
             [1mprior to setting the terminal type[22m.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             [1mblacktext [22mforces all text to be written in black even in
             color mode;

             The epslatex driver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r,c), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.  See also the documentation for the [1mpslatex [22mter-
             minal driver.  To create multiline labels, use \short-
             stack, for example










   GNUPLOT 4.1                                                      293


                set ylabel '[r]{\shortstack{first line \\ second
             line}}'

             The [1mback [22moption of [1mset label [22mcommands is handled slightly
             different than in other terminals. Labels using 'back' are
             printed behind all other elements of the plot while labels
             using 'front' are printed above everything else.

             The driver produces two different files, one for the eps
             part of the figure and one for the LaTeX part. The name of
             the LaTeX file is taken from the [1mset output [22mcommand. The
             name of the eps file is derived by replacing the file
             extension (normally [1m.tex[22m) with [1m.eps [22minstead.  There is no
             LaTeX output if no output file is given!  Remember to
             close the [1moutput file [22mbefore next plot unless in [1mmultiplot[0m
             mode.

             In your LaTeX documents use '\input{filename}' to include
             the figure.  The [1m.eps [22mfile is included by the command
             \includegraphics{...}, so you must also include \usepack-
             age{graphicx} in the LaTeX preamble.  If you want to use
             coloured text (option [1mtextcolour[22m) you also have to include
             \usepackage{color} in the LaTeX preamble.

             Pdf files can be made from the eps file using 'epstopdf'.
             If the graphics package is properly configured, the LaTeX
             files can also be processed by pdflatex without changes,
             using the pdf files instead of the eps files.  The behav-
             iour concerning font selection depends on the header mode.
             In all cases, the given font size is used for the calcula-
             tion of proper spacing. When not using the [1mstandalone [22mmode
             the actual LaTeX font and font size at the point of inclu-
             sion is taken, so use LaTeX commands for changing fonts.
             If you use e.g. 12pt as font size for your LaTeX document,
             use '"" 12' as options. The font name is ignored. If using
             [1mstandalone [22mthe given font and font size are used, see
             below for a detailed description.

             If text is printed coloured is controlled by the TeX
             booleans \ifGPcolor and \ifGPblacktext. Only if \ifGPcolor
             is true and \ifGPblacktext is false, text is printed
             coloured. You may either change them in the generated TeX
             file or provide them globally in your TeX file, for exam-
             ple by using
                \newif\ifGPblacktext
                \GPblacktexttrue
             in the preamble of your document. The local assignment is
             only done if no global value is given.

             When using the epslatex terminal give the name of the TeX
             file in the [1mset output [22mcommand including the file exten-
             sion (normally ".tex").  The eps filename is generated by
             replacing the extension by ".eps".










   GNUPLOT 4.1                                                      294


             If using the [1mstandalone [22mmode a complete LaTeX header is
             added to the LaTeX file; and "-inc" is added to the file-
             name of the eps file.  The [1mstandalone [22mmode generates a TeX
             file that produces output with the correct size when using
             dvips, pdfTeX, or VTeX.  The default, [1minput[22m, generates a
             file that has to be included into a LaTeX document using
             the \input command.

             If a font other than "" or "default" is given it is inter-
             preted as LaTeX font name.  It contains up to three parts,
             separated by a comma: 'fontname,fontseries,fontshape'.  If
             the default fontshape or fontseries are requested, they
             can be omitted.  Thus, the real syntax for the fontname is
             '[fontname][,fontseries][,fontshape]'.  The naming conven-
             tion for all parts is given by the LaTeX font scheme.  The
             fontname is 3 to 4 characters long and is built as fol-
             lows: One character for the font vendor, two characters
             for the name of the font, and optionally one additional
             character for special fonts, e.g., 'j' for fonts with old-
             style numerals or 'x' for expert fonts. The names of many
             fonts is described in
                       http://www.tug.org/fontname/fontname.pdf
             For example, 'cmr' stands for Computer Modern Roman, 'ptm'
             for Times-Roman, and 'phv' for Helvetica.  The font series
             denotes the thickness of the glyphs, in most cases 'm' for
             normal ("medium") and 'bx' or 'b' for bold fonts.  The
             font shape is 'n' for upright, 'it' for italics, 'sl' for
             slanted, or 'sc' for small caps, in general.  Some fonts
             may provide different font series or shapes.

             Examples:

             Use Times-Roman boldface (with the same shape as in the
             surrounding text):
                   set terminal epslatex 'ptm,bx'
             Use Helvetica, boldface, italics:
                   set terminal epslatex 'phv,bx,it'
             Continue to use the surrounding font in slanted shape:
                   set terminal epslatex ',,sl'
             Use small capitals:
                   set terminal epslatex ',,sc'

             By this method, only text fonts are changed. If you also
             want to change the math fonts you have to use the "gnu-
             plot.cfg" file or the [1mheader [22moption, described below.

             In standalone mode, the font size is taken from the given
             font size in the [1mset terminal [22mcommand. To be able to use a
             specified font size, a file "size<size>.clo" has to reside
             in the LaTeX search path.  By default, 10pt, 11pt, and
             12pt are supported.  If the package "extsizes" is
             installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.











   GNUPLOT 4.1                                                      295


             The [1mheader [22moption takes a string as argument.  This string
             is written into the generated LaTeX file.  If using the
             [1mstandalone [22mmode, it is written into the preamble, directly
             before the \begin{document} command.  In the [1minput [22mmode,
             it is placed directly after the \begingroup command to
             ensure that all settings are local to the plot.

             Examples:

             Use T1 fontencoding, change the text and math font to
             Times-Roman as well as the sans-serif font to Helvetica:
                 set terminal epslatex standalone header \
                 "\\usepackage[T1]{fontenc}\n\\usepackage{math-
             ptmx}\n\\usepackage{helvet}"
             Use a boldface font in the plot, not influencing the text
             outside the plot:
                 set terminal epslatex input header "\\bfseries"

             If the file "gnuplot.cfg" is found by LaTeX it is input in
             the preamble the LaTeX document, when using [1mstandalone[0m
             mode.  It can be used for further settings, e.g., changing
             the document font to Times-Roman, Helvetica, and Courier,
             including math fonts (handled by "mathptmx.sty"):
                   \usepackage{mathptmx}
                   \usepackage[scaled=0.92]{helvet}
                   \usepackage{courier}
             The file "gnuplot.cfg" is loaded before the header infor-
             mation given by the [1mheader [22mcommand.  Thus, you can use
             [1mheader [22mto overwrite some of settings performed using "gnu-
             plot.cfg"




             [1m95.20.  Epson_180dpi[0m


             This driver supports a family of Epson printers and deriv-
             atives.

             [1mepson_180dpi [22mand [1mepson_60dpi [22mare drivers for Epson LQ-
             style 24-pin printers with resolutions of 180 and 60 dots
             per inch, respectively.

             [1mepson_lx800 [22mis a generic 9-pin driver appropriate for
             printers like the Epson LX-800, the Star NL-10 and
             NX-1000, the PROPRINTER, and so forth.

             [1mnec_cp6 [22mis generic 24-pin driver that can be used for
             printers like the NEC CP6 and the Epson LQ-800.

             The [1mokidata [22mdriver supports the 9-pin OKIDATA 320/321
             Standard printers.










   GNUPLOT 4.1                                                      296


             The [1mstarc [22mdriver is for the Star Color Printer.

             The [1mtandy_60dpi [22mdriver is for the Tandy DMP-130 series of
             9-pin, 60-dpi printers.

             The [1mdpu414 [22mdriver is for the Seiko DPU-414 thermal
             printer.

             [1mnec_cp6 [22mhas the options:

             Syntax:
                   set terminal nec_cp6 {monochrome | colour | draft}

             which defaults to monochrome.

             [1mdpu414 [22mhas the options:

             Syntax:
                   set terminal dpu414 {small | medium | large} {normal
             | draft}

             which defaults to medium (=font size) and normal.  Pre-
             ferred combinations are [1mmedium normal [22mand [1msmall draft[22m.




             [1m95.21.  Excl[0m


             The [1mexcl [22mterminal driver supports Talaris printers such as
             the EXCL Laser printer and the 1590.  It has no options.



             [1m95.22.  Fig[0m


             The [1mfig [22mterminal device generates output in the Fig graph-
             ics language.

             Syntax:
                   set terminal fig {monochrome | color}
                                    {landscape | portrait}
                                    {small | big | size <xsize>
             <ysize>}
                                    {metric | inches}
                                    {pointsmax <max_points>}
                                    {solid | dashed}
                                    {font "<fontname>{,<fontsize>}"}
                                    {textnormal | {textspecial texthid-
             den textrigid}}
                                    {{thickness|linewidth} <units>}










   GNUPLOT 4.1                                                      297


                                    {depth <layer>}
                                    {version <number>}

             [1mmonochrome [22mand [1mcolor [22mdetermine whether the picture is
             black-and-white or [1mcolor[22m.  [1msmall [22mand [1mbig [22mproduce a 5x3 or
             8x5 inch graph in the default [1mlandscape [22mmode and 3x5 or
             5x8 inches in [1mportrait [22mmode.  [1msize [22msets (overrides) the
             size of the drawing area to <xsize>*<ysize> in units of
             inches or centimeters depending on the [1minches [22mor [1mmetric[0m
             setting in effect.  The latter settings is also used as
             default units for editing with "xfig".

             [1mpointsmax <max_points> [22msets the maximum number of points
             per polyline.

             [1msolid [22minhibits automatic usage of [1mdash[22med lines when solid
             linestyles are used up, which otherwise occurs.

             [1mfont [22msets the text font face to <fontname> and its size to
             <fontsize> points. [1mtextnormal [22mresets the text flags and
             selects postscript fonts, [1mtextspecial [22msets the text flags
             for LaTeX specials, [1mtexthidden [22msets the hidden flag and
             [1mtextrigid [22mthe rigid flag.

             [1mdepth [22msets the default depth layer for all lines and text.
             The default depth is 10 to leave room for adding material
             with "xfig" on top of the plot.

             [1mversion [22msets the format version of the generated fig out-
             put. Currently only versions 3.1 and 3.2 are supported.

             [1mthickness [22msets the default line thickness, which is 1 if
             not specified.  Overriding the thickness can be achieved
             by adding a multiple of 100 to the [1mlinetype [22mvalue for a
             [1mplot [22mcommand.  In a similar way the [1mdepth [22mof plot elements
             (with respect to the default depth) can be controlled by
             adding a multiple of 1000 to <linetype>.  The depth is
             then <layer> + <linetype>/1000 and the thickness is
             (<linetype>%1000)/100 or, if that is zero, the default
             line thickness. [1mlinewidth [22mis a synonym for [1mthickness[22m.

             Additional point-plot symbols are also available with the
             [1mfig [22mdriver. The symbols can be used through [1mpointtype [22mval-
             ues % 100 above 50, with different fill intensities con-
             trolled by <pointtype> % 5 and outlines in black (for
             <pointtype> % 10 < 5) or in the current color.  Available
             symbols are
                     50 - 59:  circles
                     60 - 69:  squares
                     70 - 79:  diamonds
                     80 - 89:  upwards triangles
                     90 - 99:  downwards triangles
             The size of these symbols is linked to the font size.  The










   GNUPLOT 4.1                                                      298


             depth of symbols is by default one less than the depth for
             lines to achieve nice error bars.  If <pointtype> is above
             1000, the depth is <layer> + <pointtype>/1000-1.  If
             <pointtype>%1000 is above 100, the fill color is (<point-
             type>%1000)/100-1.

             Available fill colors are (from 1 to 9): black, blue,
             green, cyan, red, magenta, yellow, white and dark blue (in
             monochrome mode: black for 1 to 6 and white for 7 to 9).

             See [1mplot with [22mfor details of <linetype> and <pointtype>.

             The [1mbig [22moption is a substitute for the [1mbfig [22mterminal in
             earlier versions, which is no longer supported.

             Examples:
                   set terminal fig monochrome small pointsmax 1000  #
             defaults

                   plot 'file.dat' with points linetype 102 pointtype
             759
             would produce circles with a blue outline of width 1 and
             yellow fill color.

                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 554
             would produce errorbars with black lines and circles
             filled red.  These circles are one layer above the lines
             (at depth 9 by default).

             To plot the error bars on top of the circles use
                   plot 'file.dat' using 1:2:3 with err linetype 1
             pointtype 2554



             [1m95.23.  Ggi[0m


             The [1mggi [22mdriver can run on different targets as X or
             svgalib.

             Syntax:
                set terminal ggi [acceleration <integer>] [[mode]
             {mode}]

             In X the window cannot be resized using window manager
             handles, but the mode can be given with the mode option,
             e.g.:
              - V1024x768
              - V800x600
              - V640x480
              - V320x200










   GNUPLOT 4.1                                                      299


             Please refer to the ggi documentation for other modes. The
             'mode' keyword is optional. It is recommended to select
             the target by environment variables as explained in the
             libggi manual page. To get DGA on X, you should for exam-
             ple
                bash> export GGI_DISPLAY=DGA
                csh>  setenv GGI_DISPLAY DGA

             'acceleration' is only used for targets which report rela-
             tive pointer motion events (e.g. DGA) and is a strictly
             positive integer multiplication factor for the relative
             distances.  The default for acceleration is 7.

             Examples:
                set term ggi acc 10
                set term ggi acc 1 mode V1024x768
                set term ggi V1024x768



             [1m95.24.  Gif[0m


             Syntax:
                   set terminal gif
                          {{no}enhanced}
                          {{no}transparent} {rounded|butt}
                          {linewidth <lw>} {dashlength <dl>}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {animate {delay <d>} {loop <n>} {{no}opti-
             mize}}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  GIF plots may be viewed interactively by
             piping the output to the 'display' program from the
             ImageMagick package as follows:
                            set term gif
                            set output '| display gif:-'
             You can view the output from successive plot commands
             interactively by typing <space> in the display window.  To
             save the current plot to a file, left click in the display
             window and choose [1msave[22m.

             [1mtransparent [22minstructs the driver to make the background
             color transparent.  Default is [1mnotransparent[22m.

             The [1mlinewidth [22mand [1mdashlength [22moptions are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.










   GNUPLOT 4.1                                                      300


             [1mbutt [22minstructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is [1mrounded[22m.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term gif font arial 11
                  set term gif font "arial,11"
             For more information please see the separate section under
             [1mfonts[22m.

             The [1manimate [22moption is available only if your local gd
             library supports the creation of animated gifs. The
             default delay between display of successive images may be
             specified in units of 1/100 second (default 5).  The
             actual delay may vary depending on the program used as a
             viewer.  Number of animation loops can be specified,
             default 0 means infinity.  An animation sequence is termi-
             nated by the next [1mset output [22mor [1mset term [22mcommand.  The
             [1moptimize [22moption has two effects on the animation.

             1) A single color map is used for the entire animation.
             This requires that all colors used in any frame of the
             animation are already defined in the first frame.

             2) If possible, only the portions of a frame that differ
             from the previous frame are stored in the animation file.
             This space saving may not be possible if the animation
             uses transparency.

             Both of these optimizations are intended to produce a
             smaller output file, but the decrease in size is probably
             only significant for long animations or very small frame
             sizes.  The [1mnooptimize [22moption turns off both of the
             effects just described.  Each frame is stored in its
             entirety along with a private color map.  Note that it is
             possible to post-process a non-optimized animation using
             external utilities, and this post-processing can yield a
             smaller file than gnuplot's internal optimization mode.
             The default is [1mnooptimize[22m.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under [1mcanvas [22mand [1mset size[22m.  Blank space at the edges of
             the finished plot may be trimmed using the [1mcrop [22moption,
             resulting in a smaller final image size. Default is
             [1mnocrop[22m.














   GNUPLOT 4.1                                                      301


                  [1m95.24.1.  Examples[0m


                        set terminal gif medium size 640,480 background
                  '#ffffff'

                  Use the medium size built-in non-scaleable, non-
                  rotatable font.  Use white (24 bit RGB in hexadeci-
                  mal) for the non-transparent background.

                        set terminal gif font arial 14 enhanced

                  Searches for a scalable font with face name 'arial'
                  and sets the font size to 14pt.  Please see [1mfonts [22mfor
                  details of how the font search is done.  Because this
                  is a scalable font, we can use enhanced text mode.

                        set term gif animate transparent opt delay 10
                  size 200,200
                        load "animate2.dem"

                  Open the gif terminal for creation of an animated gif
                  file.  The individual frames of the animation
                  sequence are created by the script file animate2.dem
                  from the standard collection of demos.




             [1m95.25.  Gpic[0m


             The [1mgpic [22mterminal driver generates GPIC graphs in the Free
             Software Foundations's "groff" package.  The default size
             is 5 x 3 inches.  The only option is the origin, which
             defaults to (0,0).

             Syntax:
                   set terminal gpic {<x> <y>}

             where [1mx [22mand [1my [22mare in inches.

             A simple graph can be formatted using

                   groff -p -mpic -Tps file.pic > file.ps.

             The output from pic can be pipe-lined into eqn, so it is
             possible to put complex functions in a graph with the [1mset[0m
             [1mlabel [22mand [1mset {x/y}label [22mcommands.  For instance,

                   set ylab '@space 0 int from 0 to x alpha ( t ) roman
             d t@'











   GNUPLOT 4.1                                                      302


             will label the y axis with a nice integral if formatted
             with the command:

                   gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-
             package] -Tps
                       > filename.ps

             Figures made this way can be scaled to fit into a docu-
             ment.  The pic language is easy to understand, so the
             graphs can be edited by hand if need be.  All co-ordinates
             in the pic-file produced by [1mgnuplot [22mare given as x+gnu-
             plotx and y+gnuploty.  By default x and y are given the
             value 0.  If this line is removed with an editor in a num-
             ber of files, one can put several graphs in one figure
             like this (default size is 5.0x3.0 inches):

                   .PS 8.0
                   x=0;y=3
                   copy "figa.pic"
                   x=5;y=3
                   copy "figb.pic"
                   x=0;y=0
                   copy "figc.pic"
                   x=5;y=0
                   copy "figd.pic"
                   .PE

             This will produce an 8-inch-wide figure with four graphs
             in two rows on top of each other.

             One can also achieve the same thing by the command

                   set terminal gpic x y

             for example, using

                   .PS 6.0
                   copy "trig.pic"
                   .PE



             [1m95.26.  Grass[0m


             The [1mgrass [22mterminal driver gives [1mgnuplot [22mcapabilities to
             users of the GRASS geographic information system.  Contact
             grassp-list@moon.cecer.army.mil for more information.
             Pages are written to the current frame of the GRASS Graph-
             ics Window.  There are no options.













   GNUPLOT 4.1                                                      303


             [1m95.27.  Hp2623a[0m


             The [1mhp2623a [22mterminal driver supports the Hewlett Packard
             HP2623A.  It has no options.



             [1m95.28.  Hp2648[0m


             The [1mhp2648 [22mterminal driver supports the Hewlett Packard
             HP2647 and HP2648.  It has no options.



             [1m95.29.  Hp500c[0m


             The [1mhp500c [22mterminal driver supports the Hewlett Packard HP
             DeskJet 500c.  It has options for resolution and compres-
             sion.

             Syntax:
                   set terminal hp500c {<res>} {<comp>}

             where [1mres [22mcan be 75, 100, 150 or 300 dots per inch and
             [1mcomp [22mcan be "rle", or "tiff".  Any other inputs are
             replaced by the defaults, which are 75 dpi and no compres-
             sion.  Rasterization at the higher resolutions may require
             a large amount of memory.



             [1m95.30.  Hpgl[0m


             The [1mhpgl [22mdriver produces HPGL output for devices like the
             HP7475A plotter.  There are two options which can be set:
             the number of pens and [1meject[22m, which tells the plotter to
             eject a page when done.  The default is to use 6 pens and
             not to eject the page when done.

             The international character sets ISO-8859-1 and CP850 are
             recognized via [1mset encoding iso_8859_1 [22mor [1mset encoding[0m
             [1mcp850 [22m(see [1mset encoding [22mfor details).

             Syntax:
                   set terminal hpgl {<number_of_pens>} {eject}

             The selection

                   set terminal hpgl 8 eject










   GNUPLOT 4.1                                                      304


             is equivalent to the previous [1mhp7550 [22mterminal, and the
             selection

                   set terminal hpgl 4

             is equivalent to the previous [1mhp7580b [22mterminal.

             The [1mpcl5 [22mdriver supports plotters such as the Hewlett-
             Packard Designjet 750C, the Hewlett-Packard Laserjet III,
             and the Hewlett-Packard Laserjet IV.  It actually uses
             HPGL-2, but there is a name conflict among the terminal
             devices.  It has several options which must be specified
             in the order indicated below:

             Syntax:
                   set terminal pcl5 {mode <mode>} {<plotsize>}
                       {{color {<number_of_pens>}} | monochrome} {solid
             | dashed}
                       {font <font>} {size <fontsize>} {pspoints | nop-
             spoints}

             <mode> is [1mlandscape [22mor [1mportrait[22m. <plotsize> is the physi-
             cal plotting size of the plot, which is one of the follow-
             ing: [1mletter [22mfor standard (8 1/2" X 11") displays, [1mlegal[0m
             for (8 1/2" X 14") displays, [1mnoextended [22mfor (36" X 48")
             displays (a letter size ratio) or, [1mextended [22mfor (36" X
             55") displays (almost a legal size ratio).  [1mcolor [22mis for
             multi-pen (i.e. color) plots, and <number_of_pens> is the
             number of pens (i.e. colors) used in color plots. [1mmono-[0m
             [1mchrome [22mis for one (e.g. black) pen plots. [1msolid [22mdraws all
             lines as solid lines, or [1mdashed [22mwill draw lines with dif-
             ferent dashed and dotted line patterns.  <font> is [1mstick[22m,
             [1munivers[22m, [1mcg_times[22m, [1mzapf_dingbats[22m, [1mantique_olive[22m, [1marial[22m,
             [1mcourier[22m, [1mgaramond_antigua[22m, [1mletter_gothic[22m, [1mcg_omega[22m, [1malber-[0m
             [1mtus[22m, [1mtimes_new_roman[22m, [1mclarendon[22m, [1mcoronet[22m, [1mmarigold[22m, [1mtrue-[0m
             [1mtype_symbols[22m, or [1mwingdings[22m. <fontsize> is the font size in
             points.  The point type selection can be the standard
             default set by specifying [1mnopspoints[22m, or the same set of
             point types found in the postscript terminal by specifying
             [1mpspoints[22m.

             Note that built-in support of some of these options is
             printer device dependent. For instance, all the fonts are
             supposedly supported by the HP Laserjet IV, but only a few
             (e.g. univers, stick) may be supported by the HP Laserjet
             III and the Designjet 750C. Also, color obviously won't
             work on the the laserjets since they are monochrome
             devices.

             Defaults: landscape, noextended, color (6 pens), solid,
             univers, 12 point,
                       and nopspoints.











   GNUPLOT 4.1                                                      305


             With [1mpcl5 [22minternational characters are handled by the
             printer; you just put the appropriate 8-bit character
             codes into the text strings.  You don't need to bother
             with [1mset encoding[22m.

             HPGL graphics can be imported by many software packages.



             [1m95.31.  Hpljii[0m


             The [1mhpljii [22mterminal driver supports the HP Laserjet Series
             II printer.  The [1mhpdj [22mdriver supports the HP DeskJet 500
             printer.  These drivers allow a choice of resolutions.

             Syntax:
                   set terminal hpljii | hpdj {<res>}

             where [1mres [22mmay be 75, 100, 150 or 300 dots per inch; the
             default is 75.  Rasterization at the higher resolutions
             may require a large amount of memory.

             The [1mhp500c [22mterminal is similar to [1mhpdj[22m; [1mhp500c [22maddition-
             ally supports color and compression.



             [1m95.32.  Hppj[0m


             The [1mhppj [22mterminal driver supports the HP PaintJet and
             HP3630 printers.  The only option is the choice of font.

             Syntax:
                   set terminal hppj {FNT5X9 | FNT9X17 | FNT13X25}

             with the middle-sized font (FNT9X17) being the default.



             [1m95.33.  Imagen[0m


             The [1mimagen [22mterminal driver supports Imagen laser printers.
             It is capable of placing multiple graphs on a single page.

             Syntax:
                   set terminal imagen {<fontsize>} {portrait | land-
             scape}
                                       {[<horiz>,<vert>]}

             where [1mfontsize [22mdefaults to 12 points and the layout










   GNUPLOT 4.1                                                      306


             defaults to [1mlandscape[22m.  [1m<horiz> [22mand [1m<vert> [22mare the number
             of graphs in the horizontal and vertical directions; these
             default to unity.

             Example:
                   set terminal imagen portrait [2,3]

             puts six graphs on the page in three rows of two in por-
             trait orientation.



             [1m95.34.  Jpeg[0m


             Syntax:
                   set terminal jpeg
                          {{no}enhanced}
                          {{no}interlace}
                          {linewidth <lw>} {dashlength <dl>}
             {rounded|butt}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  In most cases, PNG is to be preferred for
             single plots, and GIF for animations.  Both are loss-less
             image formats, and produce better image quality than the
             lossy JPEG format. This is in particular noticeable for
             solid color lines against a solid background, i.e. exactly
             the sort of image typically created by gnuplot.

             The [1minterlace [22moption creates a progressive JPEG image.
             Default is [1mnointerlace[22m.

             The [1mlinewidth [22mand [1mdashlength [22moptions are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.

             [1mbutt [22minstructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is [1mrounded[22m.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term jpeg font arial 11
                  set term jpeg font "arial,11"
             For more information please see the separate section under










   GNUPLOT 4.1                                                      307


             [1mfonts[22m.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under [1mcanvas [22mand [1mset size[22m.  Blank space at the edges of
             the finished plot may be trimmed using the [1mcrop [22moption,
             resulting in a smaller final image size. Default is
             [1mnocrop[22m.




             [1m95.35.  Kyo[0m


             The [1mkyo [22mand [1mprescribe [22mterminal drivers support the Kyocera
             laser printer.  The only difference between the two is
             that [1mkyo [22muses "Helvetica" whereas [1mprescribe [22muses
             "Courier".  There are no options.



             [1m95.36.  Latex[0m


             Syntax:
                   set terminal {latex | emtex} {default |
             {courier|roman} {<fontsize>}}
                                {size <XX>{unit}, <YY>{unit}} {rotate |
             norotate}

             By default the plot will inherit font settings from the
             embedding document.  You have the option of forcing either
             Courier (cmtt) or Roman (cmr) fonts instead. In this case
             you may also specify a fontsize.  Unless your driver is
             capable of building fonts at any size (e.g. dvips), stick
             to the standard 10, 11 and 12 point sizes.

             METAFONT users beware: METAFONT does not like odd sizes.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally.  If the text string begins with '[', you need to
             follow this with a position specification (up to two out
             of t,b,l,r), ']{', the text itself, and finally '}'.  The
             text itself may be anything LaTeX can typeset as an LR-
             box.  '\rule{}{}'s may help for best positioning.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the










   GNUPLOT 4.1                                                      308


             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.  Other point types use symbols
             from the amssymb package.

             The default size for the plot is 5 inches by 3 inches. The
             [1msize [22moption changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possible (currently only cm).

             If 'rotate' is specified, rotated text, especially a
             rotated y-axis label, is possible (the packages graphics
             or graphicx are needed). The 'stacked' y-axis label mecha-
             nism is then deactivated.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             [1m95.37.  Linux[0m


             The [1mlinux [22mdriver has no additional options to specify.  It
             looks at the environment variable GSVGAMODE for the
             default mode; if not set, it uses 1024x768x256 as default
             mode or, if that is not possible, 640x480x16 (standard
             VGA).



             [1m95.38.  Lua[0m


             The [1mlua [22mgeneric terminal driver works in conjunction with
             an external Lua script to create a target-specific plot
             file.  Currently the only supported target is TikZ ->
             pdflatex.

             Information about Lua is available at http://www.lua.org .

             Syntax:
                set terminal lua <target name> | "<file name>"
                                    {<script_args> ...}
                                    {help}










   GNUPLOT 4.1                                                      309


             A 'target name' or 'file name' (in quotes) for a script is
             mandatory.  If a 'target name' for the script is given,
             the terminal will look for "gnuplot-<target name>.lua" in
             the local directory and on failure in the environmental
             variable GNUPLOT_LUA_DIR.

             All arguments will be provided to the selected script for
             further evaluation. E.g. 'set term lua tikz help' will
             cause the script itself to print additional help on
             options and choices for the script.




                  [1m95.38.1.  Lua tikz[0m


                  The TikZ driver is one output mode of the generic Lua
                  terminal.

                  Syntax:
                      set terminal lua tikz

                       {latex | tex | context}
                       {color | monochrome}
                       {dashed | solid}
                       {nooriginreset | originreset}
                       {nogparrows | gparrows}
                       {nogppoints | gppoints}
                       {picenvironment | nopicenvironment}
                       {noclip | clip}
                       {notightboundingbox | tightboundingbox}
                       {background "<colorpec>"}
                       {size <x>{unit},<y>{unit}}
                       {scale <x>,<y>}
                       {plotsize <x>{unit},<y>{unit}}
                       {charsize <x>{unit},<y>{unit}}
                       {font "<fontdesc>"}
                       {{fontscale | textscale} <scale>}
                       {nofulldoc | nostandalone | fulldoc | stand-
                  alone}
                       {{preamble | header} "<preamble_string>"}
                       {tikzplot <ltn>,...}
                       {notikzarrows | tikzarrows}
                       {rgbimages | cmykimages}
                       {noexternalimages|externalimages}
                       {bitmap | nobitmap}
                       {providevars <var name>,...}
                       {createstyle}
                       {help}

                  For all options that expect lengths as their argu-
                  ments they will default to 'cm' if no unit is










   GNUPLOT 4.1                                                      310


                  specified. For all lengths the following units may be
                  used: 'cm', 'mm', 'in' or 'inch', 'pt', 'pc', 'bp',
                  'dd', 'cc'. Blanks between numbers and units are not
                  allowed.

                  'monochrome' disables line coloring and switches to
                  grayscaled fills.

                  'solid' use only solid lines.

                  'originreset' moves the origin of the TikZ picture to
                  the lower left corner of the plot. It may be used to
                  align several plots within one tikzpicture environ-
                  ment. This is not tested with multiplots and pm3d
                  plots!

                  'gparrows' use gnuplot's internal arrow drawing func-
                  tion instead of the ones provided by TikZ.

                  'gppoints' use gnuplot's internal plotmark drawing
                  function instead of the ones provided by TikZ.

                  'nopicenvironment' omits the declaration of the
                  'tikzpicture' environment in order to set it manu-
                  ally. This permits putting some PGF/TikZ code
                  directly before or after the plot.

                  'clip' crops the plot at the defined canvas size.
                  Default is 'noclip' by which only a minimum bounding
                  box of the canvas size is set. Neither a fixed bound-
                  ing box nor a crop box is set if the 'plotsize' or
                  'tightboundingbox' option is used.

                  If 'tightboundingbox' is set the 'clip' option is
                  ignored and the final bounding box is the natural
                  bounding box calculated by tikz.

                  'background' sets the background color to the value
                  specified in the <colorpec> argument. <colorspec>
                  must be a valid color name or a 3 byte RGB code as a
                  hexadecimal number with a preceding number sign
                  ('#'). E.g. '#ff0000' specifies pure red. If omitted
                  the background is transparent.

                  The 'size' option expects two lenghts <x> and <y> as
                  the canvas size. The default size of the canvas is
                  12.5cm x 8.75cm.

                  The 'scale' option works similar to the 'size' option
                  but expects scaling factors <x> and <y> instead of
                  lengths.

                  The 'plotsize' option permits setting the size of the










   GNUPLOT 4.1                                                      311


                  plot area instead of the canvas size, which is the
                  usual gnuplot behaviour.  Using this option may lead
                  to slightly asymmetric tic lengths.  Like 'originre-
                  set' this option may not lead to convenient results
                  if used with multiplots or pm3d plots. An alternative
                  approach is to set all margins to zero and to use the
                  'noclip' option.  The plot area has then the dimen-
                  sions of the given canvas sizes.

                  The 'charsize' option expects the average horizontal
                  and vertical size of the used font. Look at the gen-
                  erated style file for an example of how to use it
                  from within your TeX document.

                  'fontscale' or 'textscale' expects a scaling factor
                  as a parameter.  All texts in the plot are scaled by
                  this factor then.

                  The options 'tex', 'latex' and 'context' choose the
                  TeX output format. LaTeX is the default. To load the
                  style file put the according line at the beginning of
                  your document:
                    \input gnuplot-lua-tikz.tex    % (for plain TeX)
                    \usepackage{gnuplot-lua-tikz}  % (for LaTeX)
                    \usemodule[gnuplot-lua-tikz]   % (for ConTeXt)

                  'createstyle' derives the TeX/LaTeX/ConTeXt styles
                  from the script and writes them to the appropriate
                  files.

                  'fulldoc' or 'standalone' produces a full LaTeX docu-
                  ment for direct compilation.

                  'preamble' or 'header' may be used to put any addi-
                  tional LaTeX code into the document preamble in
                  standalone mode.

                  With the 'tikzplot' option the '\path plot' command
                  will be used instead of only '\path'. The following
                  list of numbers of linetypes (<ltn>,...) defines the
                  affected plotlines. There exists a plotstyle for
                  every linetype. The default plotstyle is 'smooth' for
                  every linetype >= 1.

                  By using the 'tikzarrows' option the gnuplot arrow
                  styles defined by the user will be mapped to TikZ
                  arrow styles. This is done by 'misusing' the angle
                  value of the arrow definition. E.g. an arrow style
                  with the angle '7' will be mapped to the TikZ style
                  'gp arrow 7' ignoring all the other given values. By
                  default the TikZ terminal uses the stealth' arrow
                  tips for all arrows. To obtain the default gnuplot
                  behaviour please use the 'gparrows' option.










   GNUPLOT 4.1                                                      312


                  With 'cmykimages' the CMYK color model will be used
                  for inline image data instead of the RGB model. All
                  other colors (like line colors etc.) are not affected
                  by this option, since they are handled e.g. by
                  LaTeX's xcolor package. This option is ignored if
                  images are externalized.

                  By using the 'externalimages' option all bitmap
                  images will be written as external PNG images and
                  included at compile time of the document.  Generating
                  DVI and later postscript files requires to convert
                  the PNGs into EPS files in a seperate step e.g. by
                  using ImageMagick's [1mconvert[22m.  Transparent bitmap
                  images are always generated as an external PNGs.

                  The 'nobitmap' option let images be rendered as
                  filled rectangles instead of the nativ PS or PDF
                  inline image format. This option is ignored if images
                  are externalized.

                  The 'providevars' options makes gnuplot's internal
                  and user variables available by using the '\gpget-
                  var{<var name>}' commmand within the TeX script. Use
                  gnuplot's 'show variables all' command to see the
                  list of valid variables.

                  The <fontdesc> string may contain any valid
                  TeX/LaTeX/ConTeXt font commands like e.g. '\small'.
                  It is passed directly as a node parameter in form of
                  "font={<fontdesc>}". This can be 'misused' to add
                  further code to a node, e.g. '\small,yshift=1ex' or
                  ',yshift=1ex' are also valid while the latter does
                  not change the current font settings. One exception
                  is the second argument of the list. If it is a number
                  of the form <number>{unit} it will be interpreted as
                  a fontsize like in other terminals and will be
                  appended to the first argument. If the unit is omit-
                  ted the value is interpreted as 'pt'. As an example
                  the string '\sffamily,12,fill=red' sets the font to
                  LaTeX's sans serif font at a size of 12pt and red
                  background color.  The same applies to ConTeXt, e.g.
                  '\switchtobodyfont[iwona],10' changes the font to
                  Iwona at a size of 10pt.  Plain TeX users have to
                  change the font size explicitly within the first
                  argument. The second should be set to the same value
                  to get proper scaling of text boxes.

                  Strings have to be put in single or double quotes.
                  Double quoted strings may contain special characters
                  like newlines '\n' etc.













   GNUPLOT 4.1                                                      313


             [1m95.39.  Macintosh[0m


             Syntax:
                  set terminal macintosh {singlewin | multiwin} {verti-
             cal | novertical}
                                         {size <width>, <height> |
             default}

             'singlewin' limits the output to a single window and is
             useful for animations.  'multiwin' allows multiple win-
             dows.  'vertical' is only valid under the gx option. With
             this option, rotated text will be drawn vertically. nover-
             tical turns this option off.  size <width>, <height> over-
             rides the graph size set in the preferences dialog until
             it is cleared with either 'set term mac size default' or
             'set term mac default'.

             'set term mac size default' sets the window size settings
             to those set in the preferences dialog.

             'set term mac default' sets all options to their default
             values.  Default values: nogx, multiwin, novertical.

             If you generate graphs under the multiwin option and then
             switch to singlewin, the next plot command will cause one
             more window to be created. This new window will be reused
             as long as singlewin is in effect. If you switch back to
             multiwin, generate some graphs, and then switch to sin-
             glewin again, the orginal 'singlewin' window will be
             resused if it is still open. Otherwise a new 'singlewin'
             window will be created. The 'singlewin' window is not num-
             bered.



             [1m95.40.  Mf[0m


             The [1mmf [22mterminal driver creates an input file to the META-
             FONT program.  Thus a figure may be used in the TeX docu-
             ment in the same way as is a character.

             To use a picture in a document, the METAFONT program must
             be run with the output file from [1mgnuplot [22mas input.  Thus,
             the user needs a basic knowledge of the font creating
             process and the procedure for including a new font in a
             document.  However, if the METAFONT program is set up
             properly at the local site, an unexperienced user could
             perform the operation without much trouble.

             The text support is based on a METAFONT character set.
             Currently the Computer Modern Roman font set is input, but










   GNUPLOT 4.1                                                      314


             the user is in principal free to choose whatever fonts he
             or she needs.  The METAFONT source files for the chosen
             font must be available.  Each character is stored in a
             separate picture variable in METAFONT.  These variables
             may be manipulated (rotated, scaled etc.) when characters
             are needed.  The drawback is the interpretation time in
             the METAFONT program.  On some machines (i.e. PC) the lim-
             ited amount of memory available may also cause problems if
             too many pictures are stored.

             The [1mmf [22mterminal has no options.




                  [1m95.40.1.  METAFONT Instructions[0m



                  - Set your terminal to METAFONT:
                    set terminal mf
                  - Select an output-file, e.g.:
                    set output "myfigures.mf"
                  - Create your pictures. Each picture will generate a
                  separate character. Its default size will be 5*3
                  inches. You can change the size by saying [1mset size[0m
                  [1m0.5,0.5 [22mor whatever fraction of the default size you
                  want to have.

                  - Quit [1mgnuplot[22m.

                  - Generate a TFM and GF file by running METAFONT on
                  the output of [1mgnuplot[22m.  Since the picture is quite
                  large (5*3 in), you will have to use a version of
                  METAFONT that has a value of at least 150000 for mem-
                  max.  On Unix systems these are conventionally
                  installed under the name bigmf.  For the following
                  assume that the command virmf stands for a big ver-
                  sion of METAFONT.  For example:

                  - Invoke METAFONT:
                      virmf '&plain'
                  - Select the output device: At the METAFONT prompt
                  ('*') type:
                      \mode:=CanonCX;     % or whatever printer you use
                  - Optionally select a magnification:
                      mag:=1;             % or whatever you wish
                  - Input the [1mgnuplot[22m-file:
                      input myfigures.mf
                  On a typical Unix machine there will usually be a
                  script called "mf" that executes virmf '&plain', so
                  you probably can substitute mf for virmf &plain.
                  This will generate two files: mfput.tfm and










   GNUPLOT 4.1                                                      315


                  mfput.$$$gf (where $$$ indicates the resolution of
                  your device).  The above can be conveniently achieved
                  by typing everything on the command line, e.g.: virmf
                  '&plain' '\mode:=CanonCX; mag:=1; input myfigures.mf'
                  In this case the output files will be named myfig-
                  ures.tfm and myfigures.300gf.

                  - Generate a PK file from the GF file using gftopk:
                    gftopk myfigures.300gf myfigures.300pk
                  The name of the output file for gftopk depends on the
                  DVI driver you use.  Ask your local TeX administrator
                  about the naming conventions.  Next, either install
                  the TFM and PK files in the appropriate directories,
                  or set your environment variables properly.  Usually
                  this involves setting TEXFONTS to include the current
                  directory and doing the same thing for the environ-
                  ment variable that your DVI driver uses (no standard
                  name here...).  This step is necessary so that TeX
                  will find the font metric file and your DVI driver
                  will find the PK file.

                  - To include your pictures in your document you have
                  to tell TeX the font:
                    \font\gnufigs=myfigures
                  Each picture you made is stored in a single charac-
                  ter.  The first picture is character 0, the second is
                  character 1, and so on...  After doing the above
                  step, you can use the pictures just like any other
                  characters.  Therefore, to place pictures 1 and 2
                  centered in your document, all you have to do is:
                    \centerline{\gnufigs\char0}
                    \centerline{\gnufigs\char1}
                  in plain TeX.  For LaTeX you can, of course, use the
                  picture environment and place the picture wherever
                  you wish by using the \makebox and \put macros.

                  This conversion saves you a lot of time once you have
                  generated the font; TeX handles the pictures as char-
                  acters and uses minimal time to place them, and the
                  documents you make change more often than the pic-
                  tures do.  It also saves a lot of TeX memory.  One
                  last advantage of using the METAFONT driver is that
                  the DVI file really remains device independent,
                  because no \special commands are used as in the eepic
                  and tpic drivers.



             [1m95.41.  Mif[0m


             The [1mmif [22mterminal driver produces Frame Maker MIF format
             version 3.00.  It plots in MIF Frames with the size 15*10










   GNUPLOT 4.1                                                      316


             cm, and plot primitives with the same pen will be grouped
             in the same MIF group.  Plot primitives in a [1mgnuplot [22mpage
             will be plotted in a MIF Frame, and several MIF Frames are
             collected in one large MIF Frame.  The MIF font used for
             text is "Times".

             Several options may be set in the MIF 3.00 driver.

             Syntax:
                   set terminal mif {color | colour | monochrome}
             {polyline | vectors}
                                    {help | ?}

             [1mcolour [22mplots lines with line types >= 0 in colour (MIF
             sep. 2--7) and [1mmonochrome [22mplots all line types in black
             (MIF sep. 0).  [1mpolyline [22mplots curves as continuous curves
             and [1mvectors [22mplots curves as collections of vectors.  [1mhelp[0m
             and [1m? [22mprint online help on standard error output---both
             print a short description of the usage; [1mhelp [22malso lists
             the options.

             Examples:
                   set term mif colour polylines    # defaults
                   set term mif                     # defaults
                   set term mif vectors
                   set term mif help



             [1m95.42.  Mp[0m



             The [1mmp [22mdriver produces output intended to be input to the
             Metapost program.  Running Metapost on the file creates
             EPS files containing the plots. By default, Metapost
             passes all text through TeX.  This has the advantage of
             allowing essentially  any TeX symbols in titles and
             labels.

             Syntax:
                set term mp {color | colour | monochrome}
                            {solid | dashed}
                            {notex | tex | latex}
                            {magnification <magsize>}
                            {psnfss | psnfss-version7 | nopsnfss}
                            {prologues <value>}
                            {a4paper}
                            {amstex}
                            {"<fontname> {,<fontsize>}"}

             The option [1mcolor [22mcauses lines to be drawn in color (on a
             printer or display that supports it), [1mmonochrome [22m(or










   GNUPLOT 4.1                                                      317


             nothing) selects black lines.  The option [1msolid [22mdraws
             solid lines, while [1mdashed [22m(or nothing) selects lines with
             different patterns of dashes.  If [1msolid [22mis selected but
             [1mcolor [22mis not, nearly all lines will be identical.  This
             may occasionally be useful, so it is allowed.

             The option [1mnotex [22mbypasses TeX entirely, therefore no TeX
             code can be used in labels under this option.  This is
             intended for use on old plot files or files that make fre-
             quent use of common characters like [1m$ [22mand [1m% [22mthat require
             special handling in TeX.

             The option [1mtex [22msets the terminal to output its text for
             TeX to process.

             The option [1mlatex [22msets the terminal to output its text for
             processing by LaTeX. This allows things like \frac for
             fractions which LaTeX knows about but TeX does not.  Note
             that you must set the environment variable TEX to the name
             of your LaTeX executable (normally latex) if you use this
             option or use [1mmpost --tex=<name of LaTeX executable> ...[22m.
             Otherwise metapost will try and use TeX to process the
             text and it won't work.

             Changing font sizes in TeX has no effect on the size of
             mathematics, and there is no foolproof way to make such a
             change, except by globally  setting a magnification fac-
             tor. This is the purpose of the [1mmagnification [22moption. It
             must be followed by a scaling factor. All text (NOT the
             graphs) will be scaled by this factor. Use this if you
             have math that you want at some size other than the
             default 10pt. Unfortunately, all math will be the same
             size, but see the discussion below on editing the MP out-
             put. [1mmag [22mwill also work under [1mnotex [22mbut there seems no
             point in using it as the font size option (below) works as
             well.

             The option [1mpsnfss [22muses postscript fonts in combination
             with LaTeX. Since this option only makes sense, if LaTeX
             is being used, the [1mlatex [22moption is selected automatically.
             This option includes the following packages for LaTeX:
             inputenc(latin1), fontenc(T1), mathptmx, hel-
             vet(scaled=09.2), courier, latexsym and textcomp.

             The option [1mpsnfss-version7 [22muses also postscript fonts in
             LaTeX (option [1mlatex [22mis also automatically selected), but
             uses the following packages with LaTeX: inputenc(latin1),
             fontenc(T1), times, mathptmx, helvet and courier.

             The option [1mnopsnfss [22mis the default and uses the standard
             font (cmr10 if not otherwise specified).

             The option [1mprologues [22mtakes a value as an additional










   GNUPLOT 4.1                                                      318


             argument and adds the line [1mprologues:=<value> [22mto the meta-
             post file. If a value of [1m2 [22mis specified metapost uses
             postscript fonts to generate the eps-file, so that the
             result can be viewed using e.g. ghostscript. Normally the
             output of metapost uses TeX fonts and therefore has to be
             included in a (La)TeX file before you can look at it.

             The option [1mnoprologues [22mis the default. No additional line
             specifying the prologue will be added.

             The option [1ma4paper [22madds a [1m[a4paper] [22mto the documentclass.
             Normally letter paper is used (default). Since this option
             is only used in case of LaTeX, the [1mlatex [22moption is
             selected automatically.

             The option [1mamstex [22mautomatically selects the [1mlatex [22moption
             and includes the following LaTeX packages: amsfonts, ams-
             math(intlimits). By default these packages are not
             included.

             A name in quotes selects the font that will be used when
             no explicit font is given in a [1mset label [22mor [1mset title[22m.  A
             name recognized by TeX (a TFM file exists) must be used.
             The default is "cmr10" unless [1mnotex [22mis selected, then it
             is "pcrr8r" (Courier).  Even under [1mnotex[22m, a TFM file is
             needed by Metapost. The file [1mpcrr8r.tfm [22mis the name given
             to Courier in LaTeX's psnfss package.  If you change the
             font from the [1mnotex [22mdefault, choose a font that matches
             the ASCII encoding at least in the range 32-126.  [1mcmtt10[0m
             almost works, but it has a nonblank character in position
             32 (space).

             The size can be any number between 5.0 and 99.99.  If it
             is omitted, 10.0 is used.  It is advisable to use [1mmagstep[0m
             sizes: 10 times an integer or half-integer power of 1.2,
             rounded to two decimals, because those are the most avail-
             able sizes of fonts in TeX systems.

             All the options are optional.  If font information is
             given, it must be at the end, with size (if present) last.
             The size is needed to select a size for the font, even if
             the font name includes size information.  For example, [1mset[0m
             [1mterm mp "cmtt12" [22mselects cmtt12 shrunk to the default size
             10.  This is probably not what you want or you would have
             used cmtt10.

             The following common ascii characters need special treat-
             ment in TeX:
                $, &, #, %, _;  |, <, >;  ^, ~,  \, {, and }
             The five characters $, #, &, _, and % can simply be
             escaped, e.g., [1m\$[22m.  The three characters <, >, and | can
             be wrapped in math mode, e.g., [1m$<$[22m.  The remainder require
             some TeX work-arounds.  Any good book on TeX will give










   GNUPLOT 4.1                                                      319


             some guidance.

             If you type your labels inside double quotes, backslashes
             in TeX code need to be escaped (doubled). Using single
             quotes will avoid having to do this, but then you cannot
             use [1m\n [22mfor line breaks.  As of this writing, version 3.7
             of gnuplot processes titles given in a [1mplot [22mcommand dif-
             ferently than in other places, and backslashes in TeX com-
             mands need to be doubled regardless of the style of
             quotes.

             Metapost pictures are typically used in TeX documents.
             Metapost deals with fonts pretty much the same way TeX
             does, which is different from most other document prepara-
             tion programs.  If the picture is included in a LaTeX doc-
             ument using the graphics package, or in a plainTeX docu-
             ment via epsf.tex, and then converted to PostScript with
             dvips (or other dvi-to-ps converter), the text in the plot
             will usually be handled correctly.  However, the text may
             not appear if you send the Metapost output as-is to a
             PostScript interpreter.





                  [1m95.42.1.  Metapost Instructions[0m



                  - Set your terminal to Metapost, e.g.:
                     set terminal mp mono "cmtt12" 12

                  - Select an output-file, e.g.:
                     set output "figure.mp"

                  - Create your pictures.  Each plot (or multiplot
                  group) will generate a separate Metapost begin-
                  fig...endfig group.  Its default size will be 5 by 3
                  inches.  You can change the size by saying [1mset size[0m
                  [1m0.5,0.5 [22mor whatever fraction of the default size you
                  want to have.

                  - Quit gnuplot.

                  - Generate EPS files by running Metapost on the out-
                  put of gnuplot:
                     mpost figure.mp  OR  mp figure.mp
                  The name of the Metapost program depends on the sys-
                  tem, typically [1mmpost [22mfor a Unix machine and [1mmp [22mon
                  many others.  Metapost will generate one EPS file for
                  each picture.











   GNUPLOT 4.1                                                      320


                  - To include your pictures in your document you can
                  use the graphics package in LaTeX or epsf.tex in
                  plainTeX:
                     \usepackage{graphics} % LaTeX
                     \input epsf.tex       % plainTeX
                  If you use a driver other than dvips for converting
                  TeX DVI output to PS, you may need to add the follow-
                  ing line in your LaTeX document:
                     \DeclareGraphicsRule{*}{eps}{*}{}
                  Each picture you made is in a separate file.  The
                  first picture is in, e.g., figure.0, the second in
                  figure.1, and so on....  To place the third picture
                  in your document, for example, all you have to do is:
                     \includegraphics{figure.2} % LaTeX
                     \epsfbox{figure.2}         % plainTeX

                  The advantage, if any, of the mp terminal over a
                  postscript terminal is editable output.  Considerable
                  effort went into making this output as clean as pos-
                  sible.  For those knowledgeable in the Metapost lan-
                  guage, the default line types and colors can be
                  changed by editing the arrays [1mlt[] [22mand [1mcol[][22m.  The
                  choice of solid vs dashed lines, and color vs black
                  lines can be change by changing the values assigned
                  to the booleans [1mdashedlines [22mand [1mcolorlines[22m.  If the
                  default [1mtex [22moption was in effect, global changes to
                  the text of labels can be achieved by editing the
                  [1mvebatimtex...etex [22mblock.  In particular, a LaTeX pre-
                  amble can be added if desired, and then LaTeX's
                  built-in size changing commands can be used for maxi-
                  mum flexibility. Be sure to set the appropriate MP
                  configuration variable to force Metapost to run LaTeX
                  instead of plainTeX.



             [1m95.43.  Next[0m


             Several options may be set in the next driver.

             Syntax:
                   set terminal next {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  [1mdefault[22m, which sets all options to their
             defaults; <type> is either [1mnew [22mor [1mold[22m, where [1mold [22minvokes
             the old single window; <color> is either [1mcolor [22mor [1mmono-[0m
             [1mchrome[22m; <dashed> is either [1msolid [22mor [1mdashed[22m; "<fontname>"
             is the name of a valid PostScript font; <fontsize> is the
             size of the font in PostScript points; and <title> is the










   GNUPLOT 4.1                                                      321


             title for the GnuTerm window.  Defaults are  [1mnew[22m, [1mmono-[0m
             [1mchrome[22m, [1mdashed[22m, "Helvetica", 14pt.

             Examples:
                   set term next default
                   set term next 22
                   set term next color "Times-Roman" 14
                   set term next color "Helvetica" 12 title "MyPlot"
                   set term next old

             Pointsizes may be changed with [1mset linestyle[22m.



             [1m95.44.  Openstep (next)[0m


             Several options may be set in the openstep (next) driver.

             Syntax:
                   set terminal openstep {<mode>} {<type> } {<color>}
             {<dashed>}
                              {"<fontname>"} {<fontsize>} title
             {"<newtitle>"}

             where <mode> is  [1mdefault[22m, which sets all options to their
             defaults; <type> is either [1mnew [22mor [1mold[22m, where [1mold [22minvokes
             the old single window; <color> is either [1mcolor [22mor [1mmono-[0m
             [1mchrome[22m; <dashed> is either [1msolid [22mor [1mdashed[22m; "<fontname>"
             is the name of a valid PostScript font; <fontsize> is the
             size of the font in PostScript points; and <title> is the
             title for the GnuTerm window.  Defaults are  [1mnew[22m, [1mmono-[0m
             [1mchrome[22m, [1mdashed[22m, "Helvetica", 14pt.

             Examples:
                   set term openstep default
                   set term openstep 22
                   set term openstep color "Times-Roman" 14
                   set term openstep color "Helvetica" 12 title
             "MyPlot"
                   set term openstep old

             Pointsizes may be changed with [1mset linestyle[22m.



             [1m95.45.  Pbm[0m


             Syntax:
                   set terminal pbm {<fontsize>} {<mode>} {size
             <x>,<y>}











   GNUPLOT 4.1                                                      322


             where <fontsize> is [1msmall[22m, [1mmedium[22m, or [1mlarge [22mand <mode> is
             [1mmonochrome[22m, [1mgray [22mor [1mcolor[22m.  The default plot size is 640
             pixels wide and 480 pixels high. The output size is white-
             space padded to the nearest multiple of 8 pixels on both x
             and y. This empty space may be cropped later if needed.

             The output of the [1mpbm [22mdriver depends upon <mode>: [1mmono-[0m
             [1mchrome [22mproduces a portable bitmap (one bit per pixel),
             [1mgray [22ma portable graymap (three bits per pixel) and [1mcolor [22ma
             portable pixmap (color, four bits per pixel).

             The output of this driver can be used with various image
             conversion and manipulation utilities provided by NETPBM.
             Based on Jef Poskanzer's PBMPLUS package, NETPBM provides
             programs to convert the above PBM formats to GIF, TIFF,
             MacPaint, Macintosh PICT, PCX, X11 bitmap and many others.
             Complete information is available at http://netpbm.source-
             forge.net/.

             Examples:
                   set terminal pbm small monochrome                #
             defaults
                   set terminal pbm color medium size 800,600
                   set output '| pnmrotate 45 | pnmtopng > tilted.png'
             # uses NETPBM



             [1m95.46.  Pdf[0m


             This terminal produces files in the Adobe Portable Docu-
             ment Format (PDF), useable for printing or display with
             tools like Acrobat Reader

             Syntax:
                   set terminal pdf {monochrome|color|colour}
                                    {{no}enhanced}
                                    {fname "<font>"} {fsize <fontsize>}
                                    {font "<fontname>{,<fontsize>}"}
             {fontscale <scale>}
                                    {linewidth <lw>} {rounded|butt}
                                    {solid|dashed} {dl <dashlength>}}
                                    {size <XX>{unit},<YY>{unit}}

             The default is to use a different color for each line
             type. Selecting [1mmonochome [22mwill use black for all line-
             types, in which case you probably want to select [1mdashed [22mto
             distinguish line types. Even in in mono mode you can still
             use explicit colors for filled areas or linestyles.

             where <font> is the name of the default font to use
             (default Helvetica) and <fontsize> is the font size (in










   GNUPLOT 4.1                                                      323


             points, default 12).  For help on which fonts are avail-
             able or how to install new ones, please see the documenta-
             tion for your local installation of pdflib.

             The [1menhanced [22moption enables enhanced text processing fea-
             tures (subscripts, superscripts and mixed fonts). See
             [1menhanced[22m.

             The width of all lines in the plot can be increased by the
             factor <n> specified in [1mlinewidth[22m. Similarly [1mdashlength [22mis
             a multiplier for the default dash spacing.

             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.

             The default size for PDF output is 5 inches by 3 inches.
             The [1msize [22moption changes this to whatever the user
             requests. By default the X and Y sizes are taken to be in
             inches, but other units are possible (currently only cm).




             [1m95.47.  Pdfcairo[0m


             The [1mpdfcairo [22mterminal device generates output in pdf. The
             actual drawing is done via cairo, a 2D graphics library,
             and pango, a library for laying out and rendering text.

             Syntax:
                     set term pdfcairo
                                  {{no}enhanced} {mono|color}
             {solid|dashed}
                                  {font <font>} {fontscale <scale>}
                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See [1menhanced [22mfor more
             details.

             The width of all lines in the plot can be modified by the
             factor <lw> specified in [1mlinewidth[22m. The default linewidth
             is 0.25 points.  (1 "PostScript" point = 1/72 inch = 0.353
             mm)

             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.










   GNUPLOT 4.1                                                      324


             The default size for the output is 5 inches x 3 inches.
             The [1msize [22moption changes this to whatever the user
             requests. By default the X and Y sizes are taken to be in
             inches, but other units are possible (currently only cm).
             Screen coordinates always run from 0.0 to 1.0 along the
             full length of the plot edges as specified by the [1msize[0m
             option.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the pdfcairo terminal will use 'Sans'.
             FontSize is the font size, in points. If you do not pro-
             vide it, the pdfcairo terminal will use a nominal font
             size of 12 points.  However, the default fontscale parame-
             ter for this terminal is 0.5, so the apparent font size is
             smaller than this if the pdf output is viewed at full
             size.
                For example :
                   set term pdfcairo font "Arial,12"
                   set term pdfcairo font "Arial" # to change the font
             face only
                   set term pdfcairo font ",12" # to change the font
             size only
                   set term pdfcairo font "" # to reset the font name
             and size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".

             Pango, the library used to layout the text, is based on
             utf-8. Thus, the pdfcairo terminal has to convert from
             your encoding to utf-8. The default input encoding is
             based on your 'locale'. If you want to use another encod-
             ing, make sure gnuplot knows which one you are using. See
             [1mencoding [22mfor more details.

             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the pdfcairo terminal will use the map provided
             by http://www.unicode.org/ to translate character codes to
             unicode.  Note that "the Symbol font" is to be understood
             as the Adobe Symbol font, distributed with Acrobat Reader
             as "SY______.PFB".  Alternatively, the OpenSymbol font,
             distributed with OpenOffice.org as "opens___.ttf", offers
             the same characters. Microsoft has distributed a Symbol
             font ("symbol.ttf"), but it has a different character set
             with several missing or moved mathematic characters. If
             you experience problems with your default setup (if the
             demo enhancedtext.dem is not displayed properly for exam-
             ple), you probably have to install one of the Adobe or










   GNUPLOT 4.1                                                      325


             OpenOffice Symbol fonts, and remove the Microsoft one.
             Other non-conform fonts, such as "wingdings" have been
             observed working.

             The rendering of the plot cannot be altered yet. To obtain
             the best output possible, the rendering involves two mech-
             anisms : antialiasing and oversampling.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).




             [1m95.48.  Pm[0m


             The [1mpm [22mterminal driver provides an OS/2 Presentation Man-
             ager window in which the graph is plotted.  The window is
             opened when the first graph is plotted.  This window has
             its own online help as well as facilities for printing,
             copying to the clipboard and some line type and color
             adjustments.  The [1mmultiplot [22moption is supported.

             Syntax:
                   set terminal pm {server {n}} {persist} {widelines}
             {enhanced} {"title"}

             If [1mpersist [22mis specified, each graph appears in its own
             window and all windows remain open after [1mgnuplot [22mexits.
             If [1mserver [22mis specified, all graphs appear in the same win-
             dow, which remains open when [1mgnuplot [22mexits.  This option
             takes an optional numerical argument which specifies an
             instance of the server process.  Thus multiple server win-
             dows can be in use at the same time.

             If [1mwidelines [22mis specified, all plots will be drawn with
             wide lines.  If [1menhanced [22mis specified, sub- and super-
             scripts and multiple fonts are enabled (see [1menhanced text[0m
             for details).  Font names for the core PostScript fonts
             may be abbreviated to a single letter (T/H/C/S for
             Times/Helvetica/Courier/Symbol).

             If [1mtitle [22mis specified, it will be used as the title of the
             plot window.  It will also be used as the name of the
             server instance, and will override the optional numerical
             argument.

             Linewidths may be changed with [1mset linestyle[22m.












   GNUPLOT 4.1                                                      326


             [1m95.49.  Png[0m


             Syntax:
                   set terminal png
                          {{no}enhanced}
                          {{no}transparent} {{no}interlace}
                          {{no}truecolor} {rounded|butt}
                          {linewidth <lw>} {dashlength <dl>}
                          {tiny | small | medium | large | giant}
                          {font "<face> {,<pointsize>}"} {fontscale
             <scale>}
                          {size <x>,<y>} {{no}crop}
                          {background <rgb_color>}

             PNG, JPEG and GIF images are created using the external
             library libgd.  PNG plots may be viewed interactively by
             piping the output to the 'display' program from the
             ImageMagick package as follows:
                            set term png
                            set output '| display png:-'
             You can view the output from successive plot commands
             interactively by typing <space> in the display window.  To
             save the current plot to a file, left click in the display
             window and choose [1msave[22m.

             [1mtransparent [22minstructs the driver to make the background
             color transparent.  Default is [1mnotransparent[22m.

             [1minterlace [22minstructs the driver to generate interlaced
             PNGs.  Default is [1mnointerlace[22m.

             The [1mlinewidth [22mand [1mdashlength [22moptions are scaling factors
             that affect all lines drawn, i.e. they are multiplied by
             values requested in various drawing commands.

             By default output png images use 256 indexed colors. The
             [1mtruecolor [22moption instead creates TrueColor images with 24
             bits of color information per pixel.  Transparent fill
             styles require the [1mtruecolor [22moption. See [1mfillstyle[22m.  A
             transparent background is possible in either indexed or
             TrueColor images.

             [1mbutt [22minstructs the driver to use a line drawing method
             that does not overshoot the desired end point of a line.
             This setting is only applicable for line widths greater
             than 1.  This setting is most useful when drawing horizon-
             tal or vertical lines.  Default is [1mrounded[22m.

             The details of font selection are complicated.  Two equiv-
             alent simple examples are given below:
                  set term png font arial 11
                  set term png font "arial,11"










   GNUPLOT 4.1                                                      327


             For more information please see the separate section under
             [1mfonts[22m.

             The output plot size <x,y> is given in pixels---it
             defaults to 640x480.  Please see additional information
             under [1mcanvas [22mand [1mset size[22m.  Blank space at the edges of
             the finished plot may be trimmed using the [1mcrop [22moption,
             resulting in a smaller final image size. Default is
             [1mnocrop[22m.





                  [1m95.49.1.  Examples[0m


                        set terminal png medium size 640,480 background
                  '#ffffff'

                  Use the medium size built-in non-scaleable, non-
                  rotatable font.  Use white (24-bit RGB in hexadeci-
                  mal) for the non-transparent background.

                        set terminal png font arial 14 size 800,600

                  Searches for a scalable font with face name 'arial'
                  and sets the font size to 14pt.  Please see [1mfonts [22mfor
                  details of how the font search is done.

                        set terminal png transparent truecolor enhanced

                  Use 24 bits of color information per pixel, with a
                  transparent background.  Use the [1menhanced text [22mmode
                  to control the layout of strings to be printed.




             [1m95.50.  Pngcairo[0m


             The [1mpngcairo [22mterminal device generates output in png. The
             actual drawing is done via cairo, a 2D graphics library,
             and pango, a library for laying out and rendering text.

             Syntax:
                     set term pngcairo
                                  {{no}enhanced} {mono|color}
             {solid|dashed}
                                  {{no}transparent} {{no}crop} {back-
             ground <rgbcolor>
                                  {font <font>} {fontscale <scale>}










   GNUPLOT 4.1                                                      328


                                  {linewidth <lw>} {rounded|butt}
             {dashlength <dl>}
                                  {size <XX>{unit},<YY>{unit}}

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See [1menhanced [22mfor more
             details.

             The width of all lines in the plot can be modified by the
             factor <lw>.

             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.

             The default size for the output is 640 x 480 pixels. The
             [1msize [22moption changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in pixels, but
             other units are possible (currently cm and inch).  A size
             given in centimeters or inches will be converted into pix-
             els assuming a resolution of 72 dpi. Screen coordinates
             always run from 0.0 to 1.0 along the full length of the
             plot edges as specified by the [1msize [22moption.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the pngcairo terminal will use 'Sans'.
             FontSize is the font size, in points. If you do not pro-
             vide it, the pngcairo terminal will use a size of 12
             points.
                For example :
                   set term pngcairo font "Arial,12"
                   set term pngcairo font "Arial" # to change the font
             face only
                   set term pngcairo font ",12" # to change the font
             size only
                   set term pngcairo font "" # to reset the font name
             and size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".

             Pango, the library used to layout the text, is based on
             utf-8. Thus, the pngcairo terminal has to convert from
             your encoding to utf-8. The default input encoding is
             based on your 'locale'. If you want to use another encod-
             ing, make sure gnuplot knows which one you are using. See
             [1mencoding [22mfor more details.










   GNUPLOT 4.1                                                      329


             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the pngcairo terminal will use the map provided
             by http://www.unicode.org/ to translate character codes to
             unicode.  Note that "the Symbol font" is to be understood
             as the Adobe Symbol font, distributed with Acrobat Reader
             as "SY______.PFB".  Alternatively, the OpenSymbol font,
             distributed with OpenOffice.org as "opens___.ttf", offers
             the same characters. Microsoft has distributed a Symbol
             font ("symbol.ttf"), but it has a different character set
             with several missing or moved mathematic characters. If
             you experience problems with your default setup (if the
             demo enhancedtext.dem is not displayed properly for exam-
             ple), you probably have to install one of the Adobe or
             OpenOffice Symbol fonts, and remove the Microsoft one.
             Other non-conform fonts, such as "wingdings" have been
             observed working.

             The rendering of the plot cannot be altered yet. To obtain
             the best output possible, the rendering involves two mech-
             anisms : antialiasing and oversampling.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).




             [1m95.51.  Postscript[0m


             Several options may be set in the [1mpostscript [22mdriver.

             Syntax:
                   set terminal postscript {default}
                   set terminal postscript {landscape | portrait | eps}
                                           {enhanced | noenhanced}
                                           {defaultplex | simplex |
             duplex}
                                           {fontfile [add | delete]
             "<filename>"
                                            | nofontfiles} {{no}adobeg-
             lyphnames}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}










   GNUPLOT 4.1                                                      330


                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam <sam-
             ples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {blacktext | colortext |
             colourtext}
                                           {{font} "fontname{,font-
             size}" {<fontsize>}}
                                           {fontscale <scale>}
             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in [1mpostscript pro-[0m
             [1mlogue[22m.


             [1mlandscape [22mand [1mportrait [22mchoose the plot orientation.  [1meps[0m
             mode generates EPS (Encapsulated PostScript) output, which
             is just regular PostScript with some additional lines that
             allow the file to be imported into a variety of other
             applications.  (The added lines are PostScript comment
             lines, so the file may still be printed by itself.)  To
             get EPS output, use the [1meps [22mmode and make only one plot
             per file.  In [1meps [22mmode the whole plot, including the
             fonts, is reduced to half of the default size.

             [1menhanced [22menables enhanced text mode features (subscripts,
             superscripts and mixed fonts). See [1menhanced [22mfor more
             information.  [1mblacktext [22mforces all text to be written in
             black even in color mode;

             Duplexing in PostScript is the ability of the printer to
             print on both sides of the same sheet of paper.  With
             [1mdefaultplex[22m, the default setting of the printer is used;
             with [1msimplex [22monly one side is printed; [1mduplex [22mprints on
             both sides (ignored if your printer can't do it).

             [1m"<fontname>" [22mis the name of a valid PostScript font; and
             [1m<fontsize> [22mis the size of the font in PostScript points.
             In addition to the standard postscript fonts, an oblique
             version of the Symbol font, useful for mathematics, is
             defined. It is called "Symbol-Oblique".

             [1mdefault [22msets all options to their defaults: [1mlandscape[22m,
             [1mmonochrome[22m, [1mdashed[22m, [1mdl 1.0[22m, [1mlw 1.0[22m, [1mdefaultplex[22m, [1mnoen-[0m
             [1mhanced[22m, "Helvetica" and 14pt.  Default size of a Post-
             Script plot is 10 inches wide and 7 inches high.  The
             option [1mcolor [22menables color, while [1mmonochrome [22mprefers black
             and white drawing elements. Further, [1mmonochrome [22muses gray
             [1mpalette [22mbut it does not change color of objects specified
             with an explicit [1mcolorspec[22m.  [1msolid [22mdraws all plots with
             solid lines, overriding any dashed patterns.  [1mdashlength[0m
             or [1mdl [22mscales the length of the dashed-line segments by










   GNUPLOT 4.1                                                      331


             <DL>, which is a floating-point number greater than zero.
             [1mlinewidth [22mor [1mlw [22mscales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The [1mlevel1 [22moption sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag [1mlevel1 [22mcan be toggled later by
             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.

             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.

             [1mclip [22mtells PostScript to clip all output to the bounding
             box; [1mnoclip [22mis the default.

             [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via [1mset palette functions[22m) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             [1msize [22moption changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the [1msize [22moption.  NB: [1mthis is a change from the previ-[0m
             [1mously recommended method of using the set size command[0m
             [1mprior to setting the terminal type[22m.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             Fonts listed by [1mfontfile [22mor [1mfontfile add [22mencapsulate the










   GNUPLOT 4.1                                                      332


             font definitions of the listed font from a postscript Type
             1 or TrueType font file directly into the gnuplot output
             postscript file.  Thus, the enclosed font can be used in
             labels, titles, etc.  See the section [1mpostscript fontfile[0m
             for more details.  With [1mfontfile delete[22m, a fontfile is
             deleted from the list of embedded files.  [1mnofontfiles[0m
             cleans the list of embedded fonts.

             Examples:
                   set terminal postscript default       # old post-
             script
                   set terminal postscript enhanced      # old enhpost
                   set terminal postscript landscape 22  # old psbig
                   set terminal postscript eps 14        # old epsf1
                   set terminal postscript eps 22        # old epsf2
                   set size 0.7,1.4; set term post portrait color
             "Times-Roman" 14
                   set term post "VAGRoundedBT_Regular" 14 fontfile
             "bvrr8a.pfa"

             Linewidths and pointsizes may be changed with [1mset style[0m
             [1mline[22m.

             The [1mpostscript [22mdriver supports about 70 distinct point-
             types, selectable through the [1mpointtype [22moption on [1mplot [22mand
             [1mset style line[22m.

             Several possibly useful files about [1mgnuplot[22m's PostScript
             are included in the /docs/psdoc subdirectory of the [1mgnu-[0m
             [1mplot [22mdistribution and at the distribution sites.  These
             are "ps_symbols.gpi" (a [1mgnuplot [22mcommand file that, when
             executed, creates the file "ps_symbols.ps" which shows all
             the symbols available through the [1mpostscript [22mterminal),
             "ps_guide.ps" (a PostScript file that contains a summary
             of the enhanced syntax and a page showing what the octal
             codes produce with text and symbol fonts), "ps_file.doc"
             (a text file that contains a discussion of the organiza-
             tion of a PostScript file written by [1mgnuplot[22m), and
             "ps_fontfile_doc.tex" (a LaTeX file which contains a short
             documentation concerning the encapsulation of LaTeX fonts
             with a glyph table of the math fonts).

             A PostScript file is editable, so once [1mgnuplot [22mhas created
             one, you are free to modify it to your heart's desire.
             See the [1mediting postscript [22msection for some hints.




                  [1m95.51.1.  Editing postscript[0m













   GNUPLOT 4.1                                                      333


                  The PostScript language is a very complex lan-
                  guage---far too complex to describe in any detail in
                  this document.  Nevertheless there are some things in
                  a PostScript file written by [1mgnuplot [22mthat can be
                  changed without risk of introducing fatal errors into
                  the file.

                  For example, the PostScript statement "/Color true
                  def" (written into the file in response to the com-
                  mand [1mset terminal postscript color[22m), may be altered
                  in an obvious way to generate a black-and-white ver-
                  sion of a plot.  Similarly line colors, text colors,
                  line weights and symbol sizes can also be altered in
                  straight-forward ways.  Text (titles and labels) can
                  be edited to correct misspellings or to change fonts.
                  Anything can be repositioned, and of course anything
                  can be added or deleted, but modifications such as
                  these may require deeper knowledge of the PostScript
                  language.

                  The organization of a PostScript file written by [1mgnu-[0m
                  [1mplot [22mis discussed in the text file "ps_file.doc" in
                  the docs/ps subdirectory of the gnuplot source dis-
                  tribution.



                  [1m95.51.2.  Postscript fontfile[0m


                  The [1mfontfile [22mor [1mfontfile add [22moption takes one file
                  name as argument and encapsulates this file into the
                  postscript output in order to make this font avail-
                  able for text elements (labels, tic marks, titles,
                  etc.).  The [1mfontfile delete [22moption also takes one
                  file name as argument. It deletes this file name from
                  the list of encapsulated files.

                  The postscript terminal understands some font file
                  formats: Type 1 fonts in ASCII file format (extension
                  ".pfa"), Type 1 fonts in binary file format (exten-
                  sion ".pfb"), and TrueType fonts (extension ".ttf").
                  Pfa files are understood directly, pfb and ttf files
                  are converted on the fly if appropriate conversion
                  tools are installed (see below). You have to specify
                  the full filename including the extension. Each [1mfont-[0m
                  [1mfile [22moption takes exact one font file name. This
                  option can be used multiple times in order to include
                  more than one font file.

                  The font file is searched in the working directory
                  and in all directories listed in the fontpath which
                  is determined by [1mset fontpath[22m.  In addition, the










   GNUPLOT 4.1                                                      334


                  fontpath can be set using the environment variable
                  GNUPLOT_FONTPATH. If this is not set a system depen-
                  dent default search list is used. See [1mset fontpath[0m
                  for more details.

                  For using the encapsulated font file you have to
                  specify the font name (which normally is not the same
                  as the file name). When embedding a font file by
                  using the [1mfontfile [22moption in interactive mode, the
                  font name is printed on the screen. E.g.
                     Font file 'p052004l.pfb' contains the font 'URW-
                  PalladioL-Bold'. Location:
                     /usr/lib/X11/fonts/URW/p052004l.pfb

                  When using pfa or pfb fonts, you can also find it out
                  by looking into the font file. There is a line simi-
                  lar to "/FontName /URWPalladioL-Bold def".  The mid-
                  dle string without the slash is the fontname, here
                  "URWPalladioL-Bold".  For TrueType fonts, this is not
                  so easy since the font name is stored in a binary
                  format. In addition, they often have spaces in the
                  font names which is not supported by Type 1 fonts (in
                  which a TrueType is converted on the fly). The font
                  names are changed in order to eliminate the spaces in
                  the fontnames. The easiest way to find out which font
                  name is generated for use with gnuplot, start gnuplot
                  in interactive mode and type in "set terminal post-
                  script fontfile '<filename.ttf>'".

                  For converting font files (either ttf or pfb) to pfa
                  format, the conversion tool has to read the font from
                  a file and write it to standard output. If the output
                  cannot be written to standard output, on-the-fly con-
                  version is not possible.

                  For pfb files "pfbtops" is a tool which can do this.
                  If this program is installed on your system the on
                  the fly conversion should work.  Just try to encapsu-
                  late a pfb file. If the compiled in program call does
                  not work correctly you can specify how this program
                  is called by defining the environment variable GNU-
                  PLOT_PFBTOPFA e.g. to "pfbtops %s". The [1m%s [22mwill be
                  replaced by the font file name and thus has to exist
                  in the string.

                  If you don't want to do the conversion on the fly but
                  get a pfa file of the font you can use the tool
                  "pfb2pfa" which is written in simple c and should
                  compile with any c compiler.  It is available from
                  many ftp servers, e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/utili-
                  ties/ps2mf/
                  In fact, "pfbtopfa" and "pfb2ps" do the same job.










   GNUPLOT 4.1                                                      335


                  "pfbtopfa" puts the resulting pfa code into a file,
                  whereas "pfbtops" writes it to standard output.

                  TrueType fonts are converted into Type 1 pfa format,
                  e.g.  by using the tool "ttf2pt1" which is available
                  from
                            http://ttf2pt1.sourceforge.net/
                  If the builtin conversion does not work, the conver-
                  sion command can be changed by the environment vari-
                  able GNUPLOT_TTFTOPFA. For usage with ttf2pt1 it may
                  be set to "ttf2pt1 -a -e -W 0 %s - ". Here again, [1m%s[0m
                  stands for the file name.

                  For special purposes you also can use a pipe (if
                  available for your operating system). Therefore you
                  start the file name definition with the character "<"
                  and append a program call. This program has to write
                  pfa data to standard output. Thus, a pfa file may be
                  accessed by [1mset fontfile "< cat garamond.pfa"[22m.

                  For example, including Type 1 font files can be used
                  for including the postscript output in LaTeX docu-
                  ments. The "european computer modern" font (which is
                  a variant of the "computer modern" font) is available
                  in pfb format from any CTAN server, e.g.
                            ftp://ftp.dante.de/tex-archive/fonts/ps-
                  type1/cm-super/
                  For example, the file "sfrm1000.pfb" contains the
                  normal upright fonts with serifs in the design size
                  10pt (font name "SFRM1000").  The computer modern
                  fonts, which are still necessary for mathematics, are
                  available from
                            ftp://ftp.dante.de/tex-archive/fonts/cm/ps-
                  type1/bluesky
                  With these you can use any character available in
                  TeX. However, the computer modern fonts have a
                  strange encoding. (This is why you should not use
                  cmr10.pfb for text, but sfrm1000.pfb instead.)  The
                  usage of TeX fonts is shown in one of the demos.  The
                  file "ps_fontfile_doc.tex" in the /docs/psdoc subdi-
                  rectory of the [1mgnuplot [22msource distribution contains a
                  table with glyphs of the TeX mathfonts.

                  If the font "CMEX10" is embedded (file "cmex10.pfb")
                  gnuplot defines the additional font "CMEX10-Base-
                  line". It is shifted vertically in order to fit bet-
                  ter to the other glyphs (CMEX10 has its baseline at
                  the top of the symbols).















   GNUPLOT 4.1                                                      336


                  [1m95.51.3.  Postscript prologue[0m


                  Each PostScript output file includes a %%Prolog sec-
                  tion and possibly some additional user-defined sec-
                  tions containing, for example, character encodings.
                  These sections are copied from a set of PostScript
                  prologue files that are either compiled into the gnu-
                  plot executable or stored elsewhere on your computer.
                  A default directory where these files live is set at
                  the time gnuplot is built. However, you can override
                  this default either by using the gnuplot command [1mset[0m
                  [1mpsdir [22mor by defining an environment variable GNU-
                  PLOT_PS_DIR. See [1mset psdir[22m.



                  [1m95.51.4.  Postscript adobeglyphnames[0m


                  This setting is only relevant to PostScript output
                  with UTF-8 encoding.  It controls the names used to
                  describe characters with Unicode entry points higher
                  than 0x00FF.  That is, all characters outside of the
                  Latin1 set.  In general unicode characters do not
                  have a unique name; they have only a unicode identi-
                  fication code.  However, Adobe have a recommended
                  scheme for assigning names to certain ranges of char-
                  acters (extended Latin, Greek, etc).  Some fonts use
                  this scheme, others do not.  By default, gnuplot will
                  use the Adobe glyph names.  E.g. the lower case Greek
                  letter alpha will be called /alpha.  If you specific
                  [1mnoadobeglyphnames [22mthen instead gnuplot will use
                  /uni03B1 to describe this character.  If you get this
                  setting wrong, the character may not be found even if
                  it is present in the font.  It is probably always
                  correct to use the default for Adobe fonts, but for
                  other fonts you may have to try both settings.  See
                  also [1mfontfile[22m.





             [1m95.52.  Pslatex and pstex[0m


             The [1mpslatex [22mdriver generates output for further processing
             by LaTeX, while the [1mpstex [22mdriver generates output for fur-
             ther processing by TeX. [1mpslatex [22muses \specials understand-
             able by dvips and xdvi. Figures generated by [1mpstex [22mcan be
             included in any plain-based format (including LaTeX).











   GNUPLOT 4.1                                                      337


             Syntax:
                   set terminal [pslatex | pstex] {default}
                   set terminal [pslatex | pstex]
                                           {rotate | norotate}
                                           {oldstyle | newstyle}
                                           {auxfile | noauxfile}
                                           {level1 | leveldefault}
                                           {color | colour | mono-
             chrome}
                                           {background <rgbcolor> |
             nobackground}
                                           {solid | dashed}
                                           {dashlength | dl <DL>}
                                           {linewidth | lw <LW>}
                                           {rounded | butt}
                                           {clip | noclip}
                                           {palfuncparam <sam-
             ples>{,<maxdeviation>}}
                                           {size <XX>{unit},<YY>{unit}}
                                           {<font_size>}

             If you see the error message
                   "Can't find PostScript prologue file ... "
             Please see and follow the instructions in [1mpostscript pro-[0m
             [1mlogue[22m.

             The option [1mcolor [22menables color, while [1mmonochrome [22mprefers
             black and white drawing elements. Further, [1mmonochrome [22muses
             gray [1mpalette [22mbut it does not change color of objects spec-
             ified with an explicit [1mcolorspec[22m.  [1msolid [22mdraws all plots
             with solid lines, overriding any dashed patterns.  [1mdash-[0m
             [1mlength [22mor [1mdl [22mscales the length of the dashed-line segments
             by <DL>, which is a floating-point number greater than
             zero.  [1mlinewidth [22mor [1mlw [22mscales all linewidths by <LW>.

             By default the generated PostScript code uses language
             features that were introduced in PostScript Level 2,
             notably filters and pattern-fill of irregular objects such
             as filledcurves.  PostScript Level 2 features are condi-
             tionally protected so that PostScript Level 1 interpreters
             do not issue errors but, rather, display a message or a
             PostScript Level 1 approximation.  The [1mlevel1 [22moption sub-
             stitutes PostScript Level 1 approximations of these fea-
             tures and uses no PostScript Level 2 code.  This may be
             required by some old printers and old versions of Adobe
             Illustrator.  The flag [1mlevel1 [22mcan be toggled later by
             editing a single line in the PostScript output file to
             force PostScript Level 1 interpretation.  In the case of
             files containing level 2 code, the above features will not
             appear or will be replaced by a note when this flag is set
             or when the interpreting program does not indicate that it
             understands level 2 PostScript or higher.











   GNUPLOT 4.1                                                      338


             [1mrounded [22msets line caps and line joins to be rounded; [1mbutt[0m
             is the default, butt caps and mitered joins.

             [1mclip [22mtells PostScript to clip all output to the bounding
             box; [1mnoclip [22mis the default.

             [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare
             encoded as gradients in the output. Analytic color compo-
             nent functions (set via [1mset palette functions[22m) are encoded
             as linear interpolated gradients in the postscript output:
             The color component functions are sampled at <samples>
             points and all points are removed from this gradient which
             can be removed without changing the resulting colors by
             more than <maxdeviation>. For almost every useful palette
             you may safely leave the defaults of <samples>=2000 and
             <maxdeviation>=0.003 untouched.

             The default size for postscript output is 10 inches x 7
             inches. The default for eps output is 5 x 3.5 inches.  The
             [1msize [22moption changes this to whatever the user requests. By
             default the X and Y sizes are taken to be in inches, but
             other units are possibly (currently only cm). The Bound-
             ingBox of the plot is correctly adjusted to contain the
             resized image.  Screen coordinates always run from 0.0 to
             1.0 along the full length of the plot edges as specified
             by the [1msize [22moption.  NB: [1mthis is a change from the previ-[0m
             [1mously recommended method of using the set size command[0m
             [1mprior to setting the terminal type[22m.  The old method left
             the BoundingBox unchanged and screen coordinates did not
             correspond to the actual limits of the plot.

             if [1mrotate [22mis specified, the y-axis label is rotated.
             <font_size> is the size (in pts) of the desired font.

             If [1mauxfile [22mis specified, it directs the driver to put the
             PostScript commands into an auxiliary file instead of
             directly into the LaTeX file.  This is useful if your pic-
             tures are large enough that dvips cannot handle them.  The
             name of the auxiliary PostScript file is derived from the
             name of the TeX file given on the [1mset output [22mcommand; it
             is determined by replacing the trailing [1m.tex [22m(actually
             just the final extent in the file name) with [1m.ps [22min the
             output file name, or, if the TeX file has no extension,
             [1m.ps [22mis appended.  The [1m.ps [22mis included into the [1m.tex [22mfile
             by a \special{psfile=...} command.  Remember to close the
             [1moutput file [22mbefore next plot unless in [1mmultiplot [22mmode.

             Gnuplot versions prior to version 4.2 generated plots of
             the size 5 x 3 inches using the ps(la)tex terminal while
             the current version generates 5 x 3.5 inches to be consis-
             tent with the postscript eps terminal.  In addition, the
             character width is now estimated to be 60% of the font
             size while the old epslatex terminal used 50%. To reach










   GNUPLOT 4.1                                                      339


             the old format specify the option [1moldstyle[22m.

             The pslatex driver offers a special way of controlling
             text positioning: (a) If any text string begins with '{',
             you also need to include a '}' at the end of the text, and
             the whole text will be centered both horizontally and ver-
             tically by LaTeX.  (b) If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             The options not described here are identical to the [1mPost-[0m
             [1mscript terminal[22m.  Look there if you want to know what they
             do.

             Examples:
                   set term pslatex monochrome dashed rotate       #
             set to defaults
             To write the PostScript commands into the file "foo.ps":
                   set term pslatex auxfile
                   set output "foo.tex"; plot ...; set output
             About label positioning: Use gnuplot defaults (mostly sen-
             sible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'

             Linewidths and pointsizes may be changed with [1mset style[0m
             [1mline[22m.



             [1m95.53.  Pstricks[0m


             The [1mpstricks [22mdriver is intended for use with the
             "pstricks.sty" macro package for LaTeX.  It is an alterna-
             tive to the [1meepic [22mand [1mlatex [22mdrivers.  You need
             "pstricks.sty", and, of course, a printer that understands
             PostScript, or a converter such as Ghostscript.

             PSTricks is available via anonymous ftp from the /pub
             directory at Princeton.edu.  This driver definitely does
             not come close to using the full capability of the
             PSTricks package.











   GNUPLOT 4.1                                                      340


             Syntax:
                   set terminal pstricks {hacktext | nohacktext} {unit
             | nounit}

             The first option invokes an ugly hack that gives nicer
             numbers; the second has to do with plot scaling.  The
             defaults are [1mhacktext [22mand [1mnounit[22m.



             [1m95.54.  Qms[0m


             The [1mqms [22mterminal driver supports the QMS/QUIC Laser
             printer, the Talaris 1200 and others.  It has no options.



             [1m95.55.  Qt[0m


             The [1mqt [22mterminal device generates output in a separate win-
             dow with the Qt library.  Syntax:
                     set term qt {<n>}
                                 {size <width>,<height>}
                                 {{no}enhanced}
                                 {font <font>}
                                 {title "title"}
                                 {{no}persist}
                                 {{no}raise}
                                 {{no}ctrl}
                                 {close}
                                 {widget <id>}

             Multiple plot windows are supported: [1mset terminal qt <n>[0m
             directs the output to plot window number n.

             The default window title is based on the window number.
             This title can also be specified with the keyword "title".

             Plot windows remain open even when the [1mgnuplot [22mdriver is
             changed to a different device. A plot window can be closed
             by pressing the letter 'q' while that window has input
             focus, by choosing [1mclose [22mfrom a window manager menu, or
             with [1mset term qt <n> close[22m.

             The size of the plot area is given in pixels, it defaults
             to 640x480.  In addition to that, the actual size of the
             window also includes the space reserved for the toolbar
             and the status bar.  When you resize a window, the plot is
             immediately scaled to fit in the new size of the window.
             The [1mqt [22mterminal scales the whole plot, including fonts and
             linewidths, and keeps its global aspect ratio constant.










   GNUPLOT 4.1                                                      341


             If you type [1mreplot[22m, click the [1mreplot [22micon in the terminal
             toolbar or type a new [1mplot [22mcommand, the new plot will com-
             pletely fit in the window and the font size and the
             linewidths will be reset to their defaults.

             The active plot window (the one selected by [1mset term qt[0m
             [1m<n>[22m) is interactive. Its behaviour is shared with other
             terminal types. See [1mmouse [22mfor details. It also has some
             extra icons, which are supposed to be self-explanatory.

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See [1menhanced [22mfor more
             details.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the qt terminal will use 'Sans'. Font-
             Size is the font size, in points. If you do not provide
             it, the qt terminal will use a size of 9 points.
                For example :
                   set term qt font "Arial,12"
                   set term qt font "Arial" # to change the font face
             only
                   set term qt font ",12" # to change the font size
             only
                   set term qt font "" # to reset the font name and
             size

             The Qt rendering speed is affected strongly by the render-
             ing mode used.  In Qt version 4.7 or newer this can be
             controlled by the environmental variable QT_GRAPHICSSYS-
             TEM. The options are "native", "raster", or "opengl" in
             order of increasing rendering speed.  For earlier versions
             of Qt the terminal defaults to "raster".

             To obtain the best output possible, the rendering involves
             three mechanisms : antialiasing, oversampling and hinting.
             Oversampling combined with antialiasing provides subpixel
             accuracy, so that gnuplot can draw a line from non-integer
             coordinates. This avoids wobbling effects on diagonal
             lines ('plot x' for example).  Hinting avoids the blur on
             horizontal and vertical lines caused by oversampling. The
             terminal will snap these lines to integer coordinates so
             that a one-pixel-wide line will actually be drawn on one
             and only one pixel.

             By default, the window is raised to the top of your desk-
             top when a plot is drawn. This can be controlled with the
             keyword "raise".  The keyword "persist" will prevent










   GNUPLOT 4.1                                                      342


             gnuplot from exiting before you explicitely close all the
             plot windows.  Finally, by default the key <space> raises
             the gnuplot console window, and 'q' closes the plot win-
             dow. The keyword "ctrl" allows you to replace those bind-
             ings by <ctrl>+<space> and <ctrl>+'q', respectively.

             The gnuplot outboard driver, gnuplot_qt, is searched in a
             default place chosen when the program is compiled.  You
             can override that by defining the environment variable
             GNUPLOT_DRIVER_DIR to point to a different location.



             [1m95.56.  Regis[0m


             The [1mregis [22mterminal device generates output in the REGIS
             graphics language.  It has the option of using 4 (the
             default) or 16 colors.

             Syntax:
                   set terminal regis {4 | 16}



             [1m95.57.  Sun[0m


             The [1msun [22mterminal driver supports the SunView window sys-
             tem.  It has no options.



             [1m95.58.  Svg[0m


             This terminal produces files in the W3C Scalable Vector
             Graphics format.

             Syntax:
                   set terminal svg {size <x>,<y> {|fixed|dynamic}}
                                    {{no}enhanced}
                                    {fname "<font>"} {fsize <fontsize>}
                                    {mouse} {standalone | jsdir
             <dirname>}
                                    {name <plotname>}
                                    {font "<fontname>{,<fontsize>}"}
                                    {fontfile <filename>}
                                    {rounded|butt} {solid|dashed}
             {linewidth <lw>}
                                    {background <rgb_color>}

             where <x> and <y> are the size of the SVG plot to










   GNUPLOT 4.1                                                      343


             generate, [1mdynamic [22mallows a svg-viewer to resize plot,
             whereas the default setting, [1mfixed[22m, will request an abso-
             lute size.

             [1mlinewidth <w> [22mincreases the width of all lines used in the
             figure by a factor of <w>.

             <font> is the name of the default font to use (default
             Arial) and <fontsize> is the font size (in points, default
             12). SVG viewing programs may substitute other fonts when
             the file is displayed.

             The svg terminal supports an enhanced text mode, which
             allows font and other formatting commands to be embedded
             in labels and other text strings. The enhanced text mode
             syntax is shared with other gnuplot terminal types. See
             [1menhanced [22mfor more details.

             The [1mmouse [22moption tells gnuplot to add support for mouse
             tracking and for toggling individual plots on/off by
             clicking on the corresponding key entry.  By default this
             is done by including a link that points to a script in a
             local directory, usually /usr/local/share/gnuplot/<ver-
             sion>/js.  You can change this by using the [1mjsdir [22moption
             to specify either a different local directory or a general
             URL. The latter is usually appropriate if you are embed-
             ding the svg into a web page.  Alternatively, the [1mstand-[0m
             [1malone [22moption embeds the mousing code in the svg document
             itself rather than linking to an external resource.

             When an SVG file will be used in conjunction with external
             files, e.g. if it embeds a PNG image or is referenced by
             javascript code in a web page or embedding document, then
             a unique name is required to avoid potential conflicting
             references to other SVG plots.  Use the [1mname [22moption to
             ensure uniqueness.

             SVG allows you to embed fonts directly into an SVG docu-
             ment, or to provide a hypertext link to the desired font.
             The [1mfontfile [22moption specifies a local file which is copied
             into the <defs> section of the resulting SVG output file.
             This file may either itself contain a font, or may contain
             the records necessary to create a hypertext reference to
             the desired font. Gnuplot will look for the requested file
             using the directory list in the GNUPLOT_FONTPATH environ-
             mental variable.  NB: You must embed an svg font, not a
             TrueType or PostScript font.
















   GNUPLOT 4.1                                                      344


             [1m95.59.  Svga[0m


             The [1msvga [22mterminal driver supports PCs with SVGA graphics.
             It can only be used if it is compiled with DJGPP.  Its
             only option is the font.

             Syntax:
                   set terminal svga {"<fontname>"}



             [1m95.60.  Tek40[0m


             This family of terminal drivers supports a variety of VT-
             like terminals.  [1mtek40xx [22msupports Tektronix 4010 and oth-
             ers as well as most TEK emulators.  [1mvttek [22msupports VT-like
             tek40xx terminal emulators.  The following are present
             only if selected when gnuplot is built: [1mkc-tek40xx [22msup-
             ports MS-DOS Kermit Tek4010 terminal emulators in color;
             [1mkm-tek40xx [22msupports them in monochrome. [1mselanar [22msupports
             Selanar graphics.  [1mbitgraph [22msupports BBN Bitgraph termi-
             nals.  None have any options.



             [1m95.61.  Tek410x[0m


             The [1mtek410x [22mterminal driver supports the 410x and 420x
             family of Tektronix terminals.  It has no options.



             [1m95.62.  Texdraw[0m


             The [1mtexdraw [22mterminal driver supports the LaTeX texdraw
             environment.  It is intended for use with "texdraw.sty"
             and "texdraw.tex" in the texdraw package.

             Points, among other things, are drawn using the LaTeX com-
             mands "\Diamond" and "\Box".  These commands no longer
             belong to the LaTeX2e core; they are included in the
             latexsym package, which is part of the base distribution
             and thus part of any LaTeX implementation.  Please do not
             forget to use this package.

             It has no options.













   GNUPLOT 4.1                                                      345


             [1m95.63.  Tgif[0m


             Tgif is an X11-based drawing tool---it has nothing to do
             with GIF.

             The [1mtgif [22mdriver supports different pointsizes (with [1mset[0m
             [1mpointsize[22m), different label fonts and font sizes (e.g. [1mset[0m
             [1mlabel "Hallo" at x,y font "Helvetica,34"[22m) and multiple
             graphs on the page.  The proportions of the axes are not
             changed.

             Syntax:
                   set terminal tgif {portrait | landscape | default}
             {<[x,y]>}
                                     {monochrome | color}
                                     {{linewidth | lw} <LW>}
                                     {solid | dashed}
                                     {font "<fontname>{,<fontsize>}"}

             where <[x,y]> specifies the number of graphs in the x and
             y directions on the page, [1mcolor [22menables color, [1mlinewidth[0m
             scales all linewidths by <LW>, "<fontname>" is the name of
             a valid PostScript font, and <fontsize> specifies the size
             of the PostScript font.  [1mdefaults [22msets all options to
             their defaults: [1mportrait[22m, [1m[1,1][22m, [1mcolor[22m, [1mlinwidth 1.0[22m,
             [1mdashed[22m, [1m"Helvetica,18"[22m.

             The [1msolid [22moption is usually prefered if lines are colored,
             as they often are in the editor.  Hardcopy will be black-
             and-white, so [1mdashed [22mshould be chosen for that.

             Multiplot is implemented in two different ways.

             The first multiplot implementation is the standard gnuplot
             multiplot feature:

                   set terminal tgif
                   set output "file.obj"
                   set multiplot
                   set origin x01,y01
                   set size  xs,ys
                   plot ...
                        ...
                   set origin x02,y02
                   plot ...
                   unset multiplot

             See [1mset multiplot [22mfor further information.

             The second version is the [x,y] option for the driver
             itself.  The advantage of this implementation is that
             everything is scaled and placed automatically without the










   GNUPLOT 4.1                                                      346


             need for setting origins and sizes; the graphs keep their
             natural x/y proportions of 3/2 (or whatever is fixed by
             [1mset size[22m).

             If both multiplot methods are selected, the standard
             method is chosen and a warning message is given.

             Examples of single plots (or standard multiplot):
                   set terminal tgif                  # defaults
                   set terminal tgif "Times-Roman,24"
                   set terminal tgif landscape
                   set terminal tgif landscape solid

             Examples using the built-in multiplot mechanism:
                   set terminal tgif portrait [2,4]  # portrait; 2
             plots in the x-
                                                     # and 4 in the y-
             direction
                   set terminal tgif [1,2]           # portrait; 1 plot
             in the x-
                                                     # and 2 in the y-
             direction
                   set terminal tgif landscape [3,3] # landscape; 3
             plots in both
                                                     # directions



             [1m95.64.  Tikz[0m


             This driver creates output for use with the TikZ package
             of graphics macros in TeX.  It is currently implemented
             via an external lua script, and [1mset term tikz [22mis a short
             form of the command [1mset term lua tikz[22m.  See [1mterm lua [22mfor
             more information.  Use the command [1mset term tikz help [22mto
             print terminal options.



             [1m95.65.  Tkcanvas[0m


             This terminal driver generates Tk canvas widget commands
             based on Tcl/Tk (default) or Perl.  To use it, rebuild
             [1mgnuplot [22m(after uncommenting or inserting the appropriate
             line in "term.h"), then

              gnuplot> set term tkcanvas {perltk} {interactive}
              gnuplot> set output 'plot.file'

             After invoking "wish", execute the following sequence of
             Tcl/Tk commands:










   GNUPLOT 4.1                                                      347


              % source plot.file
              % canvas .c
              % pack .c
              % gnuplot .c

             Or, for Perl/Tk use a program like this:

              use Tk;
              my $top = MainWindow->new;
              my $c = $top->Canvas->pack;
              my $gnuplot = do "plot.pl";
              $gnuplot->($c);
              MainLoop;

             The code generated by [1mgnuplot [22mcreates a procedure called
             "gnuplot" that takes the name of a canvas as its argument.
             When the procedure is called, it clears the canvas, finds
             the size of the canvas and draws the plot in it, scaled to
             fit.

             For 2-dimensional plotting ([1mplot[22m) two additional proce-
             dures are defined: "gnuplot_plotarea" will return a list
             containing the borders of the plotting area "xleft,
             xright, ytop, ybot" in canvas screen coordinates, while
             the ranges of the two axes "x1min, x1max, y1min, y1max,
             x2min, x2max, y2min, y2max" in plot coordinates can be
             obtained calling "gnuplot_axisranges".  If the "interac-
             tive" option is specified, mouse clicking on a line seg-
             ment will print the coordinates of its midpoint to stdout.
             Advanced actions can happen instead if the user supplies a
             procedure named "user_gnuplot_coordinates", which takes
             the following arguments: "win id x1s y1s x2s y2s x1e y1e
             x2e y2e x1m y1m x2m y2m", the name of the canvas and the
             id of the line segment followed by the coordinates of its
             start and end point in the two possible axis ranges; the
             coordinates of the midpoint are only filled for logarith-
             mic axes.

             The current version of [1mtkcanvas [22msupports neither [1mmultiplot[0m
             nor [1mreplot[22m.



             [1m95.66.  Tpic[0m


             The [1mtpic [22mterminal driver supports the LaTeX picture envi-
             ronment with tpic \specials.  It is an alternative to the
             [1mlatex [22mand [1meepic [22mterminal drivers.  Options are the point
             size, line width, and dot-dash interval.

             Syntax:
                   set terminal tpic <pointsize> <linewidth> <interval>










   GNUPLOT 4.1                                                      348


             where [1mpointsize [22mand [1mlinewidth [22mare integers in milli-inches
             and [1minterval [22mis a float in inches.  If a non-positive
             value is specified, the default is chosen: pointsize = 40,
             linewidth = 6, interval = 0.1.

             All drivers for LaTeX offer a special way of controlling
             text positioning: If any text string begins with '{', you
             also need to include a '}' at the end of the text, and the
             whole text will be centered both horizontally and verti-
             cally by LaTeX. --- If the text string begins with '[',
             you need to continue it with: a position specification (up
             to two out of t,b,l,r), ']{', the text itself, and
             finally, '}'. The text itself may be anything LaTeX can
             typeset as an LR-box. \rule{}{}'s may help for best posi-
             tioning.

             Examples: About label positioning: Use gnuplot defaults
             (mostly sensible, but sometimes not really best):
                    set title '\LaTeX\ -- $ \gamma $'
             Force centering both horizontally and vertically:
                    set label '{\LaTeX\ -- $ \gamma $}' at 0,0
             Specify own positioning (top here):
                    set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
             The other label -- account for long ticlabels:
                    set ylabel '[r]{\LaTeX\ -- $ \gamma
             $\rule{7mm}{0pt}}'



             [1m95.67.  Vgagl[0m


             The [1mvgagl [22mdriver is a fast linux console driver with full
             mouse and pm3d support.  It looks at the environment vari-
             able SVGALIB_DEFAULT_MODE for the default mode; if not
             set, it uses a 256 color mode with the highest available
             resolution.

             Syntax:
                set terminal vgagl \
                             background [red] [[green] [blue]] \
                             [uniform | interpolate] \
                             [mode]

             The color mode can also be given with the mode option.
             Both Symbolic names as G1024x768x256 and integers are
             allowed. The [1mbackground [22moption takes either one or three
             integers in the range [0, 255]. If only one integers is
             supplied, it is taken as gray value for the background.
             If three integers are present, the background gets the
             corresponding color.  The (mutually exclusive) options
             [1minterpolate [22mand [1muniform [22mcontrol if color interpolation is
             done while drawing triangles (on by default).










   GNUPLOT 4.1                                                      349


             To get high resolution modes, you will probably have to
             modify the configuration file of libvga, usually
             /etc/vga/libvga.conf.  Using the VESA fb is a good choice,
             but this needs to be compiled in the kernel.

             The vgagl driver uses the first *available* vga mode from
             the following list:
              - the driver which was supplied when setting vgagl, e.g.
             `set term vgagl
                G1024x768x256` would first check, if the G1024x768x256
             mode is available.
              - the environment variable SVGALIB_DEFAULT_MODE
              - G1024x768x256
              - G800x600x256
              - G640x480x256
              - G320x200x256
              - G1280x1024x256
              - G1152x864x256
              - G1360x768x256
              - G1600x1200x256




             [1m95.68.  VWS[0m


             The [1mVWS [22mterminal driver supports the VAX Windowing System.
             It has no options.  It will sense the display type (mono-
             chrome, gray scale, or color.)  All line styles are plot-
             ted as solid lines.



             [1m95.69.  Vx384[0m


             The [1mvx384 [22mterminal driver supports the Vectrix 384 and
             Tandy color printers.  It has no options.



             [1m95.70.  Windows[0m


             The [1mwindows [22mterminal is a fast interactive terminal driver
             that uses the Windows GDI to draw and write text. The
             cross-platform [1mterminal wxt [22mis also supported on Windows.

             Syntax:
                   set terminal windows {<n>}
                                        {color | monochrome}
                                        {solid | dashed}










   GNUPLOT 4.1                                                      350


                                        {enhanced | noenhanced}
                                        {font <fontspec>}
                                        {fontscale <scale>}
                                        {linewdith <scale>}
                                        {background <rgb color>}
                                        {title "Plot Window Title"}
                                        {size <width>,<height>}
                                        {position <x>,<y>}
                                        {close}

             Multiple plot windows are supported: [1mset terminal win <n>[0m
             directs the output to plot window number n.

             [1mcolor [22mand [1mmonochrome [22mselect colored or mono output, [1mdashed[0m
             and [1msolid [22mselect dashed or solid lines. Note that [1mcolor[0m
             defaults to [1msolid[22m, whereas [1mmonochrome [22mdefaults to [1mdashed[22m.
             [1menhanced [22menables enhanced text mode features (subscripts,
             superscripts and mixed fonts, see [1menhanced text [22mfor more
             information).  [1m<fontspec> [22mis in the format "<font-
             face>,<fontsize>", where "<fontface>" is the name of a
             valid Windows font, and <fontsize> is the size of the font
             in points and both components are optional.  Note that in
             previous versions of gnuplot the [1mfont [22mstatement could be
             left out and <fontsize> could be given as a number without
             double quotes. This is no longer supported.  [1mlinewidth [22mand
             [1mfontscale [22mcan be used to scale the width of lines and the
             size of text.  [1mtitle [22mchanges the title of the graph win-
             dow.  [1msize [22mdefines the width and height of the window in
             pixel and [1mposition [22mthe origin of the window i.e. the posi-
             tion of the top left corner on the screen (again in
             pixel). These options override any default settings from
             the [1mwgnuplot.ini [22mfile.

             Other options may be changed using the [1mgraph-menu [22mor the
             initialization file [1mwgnuplot.ini[22m.

             The Windows version normally terminates immediately as
             soon as the end of any files given as command line argu-
             ments is reached (i.e. in non-interactive mode), unless
             you specify [1m- [22mas the last command line option.  It will
             also not show the text-window at all, in this mode, only
             the plot.  By giving the optional argument [1m-persist [22m(same
             as for gnuplot under x11; former Windows-only options
             [1m/noend [22mor [1m-noend [22mare still accepted as well), will not
             close gnuplot. Contrary to gnuplot on other operating sys-
             tems, gnuplot's interactive command line is accessible
             after the -persist option.

             The plot window remains open when the gnuplot terminal is
             changed with a [1mset term [22mcommand. The plot window can be
             closed with [1mset term windows close[22m.

             [1mgnuplot [22msupports different methods to create printed










   GNUPLOT 4.1                                                      351


             output on Windows, see [1mwindows printing[22m. The windows ter-
             minal supports data exchange with other programs via clip-
             board and EMF files, see [1mgraph-menu[22m. You can also use the
             [1mterminal emf [22mto create EMF files.




                  [1m95.70.1.  Graph-menu[0m


                  The [1mgnuplot graph [22mwindow has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button(*) or selecting [1mOptions [22mfrom the system menu:

                  [1mCopy to Clipboard [22mcopies a bitmap and an enhanced
                  Metafile picture.

                  [1mSave as EMF... [22mallows the user to save the current
                  graph window as enhanced metafile

                  [1mPrint... [22mprints the graphics windows using a Windows
                  printer driver and allows selection of the printer
                  and scaling of the output.  The output produced by
                  [1mPrint [22mis not as good as that from [1mgnuplot[22m's own
                  printer drivers. See also [1mwindows printing[22m.

                  [1mBring to Top [22mwhen checked brings the graph window to
                  the top after every plot.

                  [1mColor [22mwhen checked enables color linestyles.  When
                  unchecked it forces monochrome linestyles.

                  [1mDouble buffer [22mactivates drawing into a memory buffer
                  before copying the graph to the screen. This avoids
                  flickering e.g. during animation and rotation of 3d
                  graphs. See [1mmouse [22mand [1mscrolling[22m.

                  [1mOversampling [22mdoubles the size of the virtual canvas.
                  It is scaled down again for drawing to the screen.
                  This gives smoother graphics but requires more memory
                  and computing time. It requires [1mdouble buffer[22m.

                  [1mAntialiasing [22mselects smoothing of lines and edges.
                  Note that this slows down drawing.

                  [1mBackground... [22msets the window background color.

                  [1mChoose Font... [22mselects the font used in the graphics
                  window.

                  [1mLine Styles... [22mallows customization of the line col-
                  ors and styles.










   GNUPLOT 4.1                                                      352


                  [1mUpdate wgnuplot.ini [22msaves the current window loca-
                  tions, window sizes, text window font, text window
                  font size, graph window font, graph window font size,
                  background color and linestyles to the initialization
                  file [1mwgnuplot.ini[22m.

                  (*) Note that this menu is only available by pressing
                  the right mouse button with [1munset mouse[22m.



                  [1m95.70.2.  Printing[0m


                  In order of preference, graphs may be printed in the
                  following ways:

                  [1m1. [22mUse the [1mgnuplot [22mcommand [1mset terminal [22mto select a
                  printer and [1mset output [22mto redirect output to a file.

                  [1m2. [22mSelect the [1mPrint... [22mcommand from the [1mgnuplot graph[0m
                  window.  An extra command [1mscreendump [22mdoes this from
                  the text window.

                  [1m3. [22mIf [1mset output "PRN" [22mis used, output will go to a
                  temporary file.  When you exit from [1mgnuplot [22mor when
                  you change the output with another [1mset output [22mcom-
                  mand, a dialog box will appear for you to select a
                  printer port.  If you choose OK, the output will be
                  printed on the selected port, passing unmodified
                  through the print manager.  It is possible to acci-
                  dentally (or deliberately) send printer output meant
                  for one printer to an incompatible printer.




                  [1m95.70.3.  Text-menu[0m


                  The [1mgnuplot text [22mwindow has the following options on
                  a pop-up menu accessed by pressing the right mouse
                  button or selecting [1mOptions [22mfrom the system menu:

                  [1mCopy to Clipboard [22mcopies marked text to the clip-
                  board.

                  [1mPaste [22mcopies text from the clipboard as if typed by
                  the user.

                  [1mChoose Font... [22mselects the font used in the text win-
                  dow.











   GNUPLOT 4.1                                                      353


                  [1mSystem Colors [22mwhen selected makes the text window
                  honor the System Colors set using the Control Panel.
                  When unselected, text is black or blue on a white
                  background.

                  [1mWrap long lines [22mwhen selected lines longer than the
                  current window width are wrapped.

                  [1mUpdate wgnuplot.ini [22msaves the current settings to the
                  initialisation file [1mwgnuplot.ini[22m, which is located in
                  the user's application data directory.




                  [1m95.70.4.  Wgnuplot.mnu[0m


                  If the menu file [1mwgnuplot.mnu [22mis found in the same
                  directory as [1mgnuplot[22m, then the menu specified in
                  [1mwgnuplot.mnu [22mwill be loaded.  Menu commands:

                   [Menu]      starts a new menu with the name on the
                  following line.
                   [EndMenu]   ends the current menu.
                   [--]        inserts a horizontal menu separator.
                   [|]         inserts a vertical menu separator.
                   [Button]    puts the next macro on a push button
                  instead of a menu.

                  Macros take two lines with the macro name (menu
                  entry) on the first line and the macro on the second
                  line.  Leading spaces are ignored.  Macro commands:

                   [INPUT]     Input string with prompt terminated by
                  [EOS] or {ENTER}
                   [EOS]       End Of String terminator. Generates no
                  output.
                   [OPEN]      Get name of a file to open, with the
                  title of the dialog
                               terminated by [EOS], followed by a
                  default filename terminated
                               by [EOS] or {ENTER}.
                   [SAVE]      Get name of a file to save.  Parameters
                  like [OPEN]
                   [DIRECTORY] Get name of a directory, with the title
                  of the dialog
                               terminated by [EOS] or {ENTER}

                  Macro character substitutions:

                   {ENTER}     Carriage Return '\r'
                   {TAB}       Tab '\011'










   GNUPLOT 4.1                                                      354


                   {ESC}       Escape '\033'
                   {^A}        '\001'
                   ...
                   {^_}        '\031'

                  Macros are limited to 256 characters after expansion.




                  [1m95.70.5.  Wgnuplot.ini[0m


                  The Windows text window and the [1mwindows [22mterminal will
                  read some of their options from the [1m[WGNUPLOT] [22msec-
                  tion of [1mwgnuplot.ini[22m.  This file is located in the
                  user's application data directory. Here's a sample
                  [1mwgnuplot.ini [22mfile:

                        [WGNUPLOT]
                        TextOrigin=0 0
                        TextSize=640 150
                        TextFont=Terminal,9
                        TextWrap=1
                        TextLines=400
                        SysColors=0
                        GraphOrigin=0 150
                        GraphSize=640 330
                        GraphFont=Arial,10
                        GraphColor=1
                        GraphToTop=1
                        GraphDoublebuffer=1
                        GraphOversampling=0
                        GraphAntialiasing=1
                        GraphBackground=255 255 255
                        Border=0 0 0 0 0
                        Axis=192 192 192 2 2
                        Line1=0 0 255 0 0
                        Line2=0 255 0 0 1
                        Line3=255 0 0 0 2
                        Line4=255 0 255 0 3
                        Line5=0 0 128 0 4


                  These settings apply to the wgnuplot text-window
                  only.  The [1mTextOrigin [22mand [1mTextSize [22mentries specify
                  the location and size of the text window.

                  The [1mTextFont [22mentry specifies the text window font and
                  size.

                  The [1mTextWrap [22mentry selects wrapping of long text
                  lines.










   GNUPLOT 4.1                                                      355


                  The [1mTextLines [22mentry specifies the number of
                  (unwrapped) lines the internal buffer of the text
                  window can hold. This value currently cannot be
                  changed from within wgnuplot.

                  See [1mtext-menu[22m.


                  The [1mGraphFont [22mentry specifies the font name and size
                  in points.

                  The five numbers given in the [1mBorder[22m, [1mAxis [22mand [1mLine[0m
                  entries are the [1mRed [22mintensity (0--255), [1mGreen [22minten-
                  sity, [1mBlue [22mintensity, [1mColor Linestyle [22mand [1mMono[0m
                  [1mLinestyle[22m.  [1mLinestyles [22mare 0=SOLID, 1=DASH, 2=DOT,
                  3=DASHDOT, 4=DASHDOTDOT.  In the sample [1mwgnuplot.ini[0m
                  file above, Line 2 is a green solid line in color
                  mode, or a dashed line in monochrome mode.  The
                  default line width is 1 pixel.  If [1mLinestyle [22mis nega-
                  tive, it specifies the width of a SOLID line in pix-
                  els.  Line1 and any linestyle used with the [1mpoints[0m
                  style must be SOLID with unit width.

                  See [1mgraph-menu[22m.



             [1m95.71.  Wxt[0m


             The [1mwxt [22mterminal device generates output in a separate
             window. The window is created by the wxWidgets library,
             where the 'wxt' comes from. The actual drawing is done via
             cairo, a 2D graphics library, and pango, a library for
             laying out and rendering text.

             Syntax:
                     set term wxt {<n>}
                                  {size <width>,<height>} {background
             <rgb_color>}
                                  {{no}enhanced}
                                  {font <font>} {fontscale <scale>}
                                  {title "title"}
                                  {dashed|solid} {dashlength <dl>}
                                  {{no}persist}
                                  {{no}raise}
                                  {{no}ctrl}
                                  {close}

             Multiple plot windows are supported: [1mset terminal wxt <n>[0m
             directs the output to plot window number n.

             The default window title is based on the window number.










   GNUPLOT 4.1                                                      356


             This title can also be specified with the keyword "title".

             Plot windows remain open even when the [1mgnuplot [22mdriver is
             changed to a different device.  A plot window can be
             closed by pressing the letter 'q' while that window has
             input focus, by choosing [1mclose [22mfrom a window manager menu,
             or with [1mset term wxt <n> close[22m.

             The size of the plot area is given in pixels, it defaults
             to 640x384.  In addition to that, the actual size of the
             window also includes the space reserved for the toolbar
             and the status bar.  When you resize a window, the plot is
             immediately scaled to fit in the new size of the window.
             Unlike other interactive terminals, the [1mwxt [22mterminal
             scales the whole plot, including fonts and linewidths, and
             keeps its global aspect ratio constant, leaving an empty
             space painted in gray.  If you type [1mreplot[22m, click the
             [1mreplot [22micon in the terminal toolbar or type a new [1mplot[0m
             command, the new plot will completely fit in the window
             and the font size and the linewidths will be reset to
             their defaults.

             The active plot window (the one selected by [1mset term wxt[0m
             [1m<n>[22m) is interactive. Its behaviour is shared with other
             terminal types. See [1mmouse [22mfor details. It also has some
             extra icons, which are supposed to be self-explanatory.

             This terminal supports an enhanced text mode, which allows
             font and other formatting commands (subscripts, super-
             scripts, etc.) to be embedded in labels and other text
             strings. The enhanced text mode syntax is shared with
             other gnuplot terminal types. See [1menhanced [22mfor more
             details.

             <font> is in the format "FontFace,FontSize", i.e. the face
             and the size comma-separated in a single string. FontFace
             is a usual font face name, such as 'Arial'. If you do not
             provide FontFace, the wxt terminal will use 'Sans'. Font-
             Size is the font size, in points. If you do not provide
             it, the wxt terminal will use a size of 10 points.
                For example :
                   set term wxt font "Arial,12"
                   set term wxt font "Arial" # to change the font face
             only
                   set term wxt font ",12" # to change the font size
             only
                   set term wxt font "" # to reset the font name and
             size

             The fonts are retrieved from the usual fonts subsystems.
             Under Windows, those fonts are to be found and configured
             in the entry "Fonts" of the control panel. Under UNIX,
             they are handled by "fontconfig".










   GNUPLOT 4.1                                                      357


             Pango, the library used to layout the text, is based on
             utf-8. Thus, the wxt terminal has to convert from your
             encoding to utf-8. The default input encoding is based on
             your 'locale'. If you want to use another encoding, make
             sure gnuplot knows which one you are using. See [1mencoding[0m
             for more details.

             Pango may give unexpected results with fonts that do not
             respect the unicode mapping. With the Symbol font, for
             example, the wxt terminal will use the map provided by
             http://www.unicode.org/ to translate character codes to
             unicode.  Pango will do its best to find a font containing
             this character, looking for your Symbol font, or other
             fonts with a broad unicode coverage, like the DejaVu
             fonts. Note that "the Symbol font" is to be understood as
             the Adobe Symbol font, distributed with Acrobat Reader as
             "SY______.PFB".  Alternatively, the OpenSymbol font, dis-
             tributed with OpenOffice.org as "opens___.ttf", offers the
             same characters. Microsoft has distributed a Symbol font
             ("symbol.ttf"), but it has a different character set with
             several missing or moved mathematic characters. If you
             experience problems with your default setup (if the demo
             enhancedtext.dem is not displayed properly for example),
             you probably have to install one of the Adobe or OpenOf-
             fice Symbol fonts, and remove the Microsoft one.  Other
             non-conform fonts, such as "wingdings" have been observed
             working.

             The rendering of the plot can be altered with a dialog
             available from the toolbar. To obtain the best output pos-
             sible, the rendering involves three mechanisms :
             antialiasing, oversampling and hinting.  Antialiasing
             allows to display non-horizontal and non-vertical lines
             smoother.  Oversampling combined with antialiasing pro-
             vides subpixel accuracy, so that gnuplot can draw a line
             from non-integer coordinates. This avoids wobbling effects
             on diagonal lines ('plot x' for example).  Hinting avoids
             the blur on horizontal and vertical lines caused by over-
             sampling. The terminal will snap these lines to integer
             coordinates so that a one-pixel-wide line will actually be
             drawn on one and only one pixel.

             By default, the window is raised to the top of your desk-
             top when a plot is drawn. This can be controlled with the
             keyword "raise".  The keyword "persist" will prevent gnu-
             plot from exiting before you explicitely close all the
             plot windows.  Finally, by default the key <space> raises
             the gnuplot console window, and 'q' closes the plot win-
             dow. The keyword "ctrl" allows you to replace those bind-
             ings by <ctrl>+<space> and <ctrl>+'q', respectively.
             These three keywords (raise, persist and ctrl) can also be
             set and remembered between sessions through the configura-
             tion dialog.










   GNUPLOT 4.1                                                      358


             [1m95.72.  X11[0m



             Syntax:
                set terminal x11 {<n> | window "<string>"}
                                 {title "<string>"}
                                 {{no}enhanced} {font <fontspec>}
                                 {linewidth LW} {solid|dashed}
                                 {{no}persist} {{no}raise} {{no}ctrlq}
                                 {close}
                                 {size XX,YY} {position XX,YY}
                set terminal x11 {reset}

             Multiple plot windows are supported: [1mset terminal x11 <n>[0m
             directs the output to plot window number n.  If n is not
             0, the terminal number will be appended to the window
             title (unless a title has been supplied manually) and the
             icon will be labeled [1mGnuplot <n>[22m.  The active window may
             be distinguished by a change in cursor (from default to
             crosshair).

             The [1mx11 [22mterminal can connect to X windows previously cre-
             ated by an outside application via the option [1mwindow [22mfol-
             lowed by a string containing the X ID for the window in
             hexadecimal format.  Gnuplot uses that external X window
             as a container since X does not allow for multiple clients
             selecting the ButtonPress event.  In this way, gnuplot's
             mouse features work within the contained plot window.

                set term x11 window "220001e"

             The x11 terminal supports enhanced text mode (see
             [1menhanced[22m), subject to the available fonts. In order for
             font size commands embedded in text to have any effect,
             the default x11 font must be scalable. Thus the first
             example below will work as expected, but the second will
             not.

                set term x11 enhanced font "arial,15"
                set title '{/=20 Big} Medium {/=5 Small}'

                set term x11 enhanced font "terminal-14"
                set title '{/=20 Big} Medium {/=5 Small}'

             Plot windows remain open even when the [1mgnuplot [22mdriver is
             changed to a different device.  A plot window can be
             closed by pressing the letter q while that window has
             input focus, or by choosing [1mclose [22mfrom a window manager
             menu.  All plot windows can be closed by specifying [1mreset[22m,
             which actually terminates the subprocess which maintains
             the windows (unless [1m-persist [22mwas specified).  The [1mclose[0m
             command can be used to close individual plot windows by










   GNUPLOT 4.1                                                      359


             number.  However, after a [1mreset[22m, those plot windows left
             due to persist cannot be closed with the command [1mclose[22m.  A
             [1mclose [22mwithout a number closes the current active plot win-
             dow.

             The gnuplot outboard driver, gnuplot_x11, is searched in a
             default place chosen when the program is compiled.  You
             can override that by defining the environment variable
             GNUPLOT_DRIVER_DIR to point to a different location.

             Plot windows will automatically be closed at the end of
             the session unless the [1m-persist [22moption was given.

             The options [1mpersist [22mand [1mraise [22mare unset by default, which
             means that the defaults (persist == no and raise == yes)
             or the command line options -persist / -raise or the Xre-
             sources are taken.  If [no]persist or [no]raise are speci-
             fied, they will override command line options and Xre-
             sources.  Setting one of these options takes place immedi-
             ately, so the behaviour of an already running driver can
             be modified.  If the window does not get raised, see dis-
             cussion in [1mraise[22m.

             The option [1mtitle "<title name>" [22mwill supply the title name
             of the window for the current plot window or plot window
             <n> if a number is given.  Where (or if) this title is
             shown depends on your X window manager.

             The size option can be used to set the size of the plot
             window.  The size option will only apply to newly created
             windows.

             The position option can be used to set the position of the
             plot window.  The position option will only apply to newly
             created windows.

             The size or aspect ratio of a plot may be changed by
             resizing the [1mgnuplot [22mwindow.

             Linewidths and pointsizes may be changed from within [1mgnu-[0m
             [1mplot [22mwith [1mset linestyle[22m.

             For terminal type [1mx11[22m, [1mgnuplot [22maccepts (when initialized)
             the standard X Toolkit options and resources such as geom-
             etry, font, and name from the command line arguments or a
             configuration file.  See the X(1) man page (or its equiva-
             lent) for a description of such options.

             A number of other [1mgnuplot [22moptions are available for the
             [1mx11 [22mterminal.  These may be specified either as command-
             line options when [1mgnuplot [22mis invoked or as resources in
             the configuration file ".Xdefaults".  They are set upon
             initialization and cannot be altered during a [1mgnuplot[0m










   GNUPLOT 4.1                                                      360


             session.  (except [1mpersist [22mand [1mraise[22m)




                  [1m95.72.1.  X11_fonts[0m


                  Upon initial startup, the default font is taken from
                  the X11 resources as set in the system or user .Xde-
                  faults file or on the command line.

                  Example:
                        gnuplot*font: lucidasans-bold-12
                  A new default font may be specified to the x11 driver
                  from inside gnuplot using
                       `set term x11 font "<fontspec>"`
                  The driver first queries the X-server for a font of
                  the exact name given.  If this query fails, then it
                  tries to interpret <fontspec> as
                  "<font>,<size>,<slant>,<weight>" and to construct a
                  full X11 font name of the form
                        -*-<font>-<weight>-<s>-*-*-<size>-*-*-*-*-*-<encod-
                  ing>

                   <font> is the base name of the font (e.g. Times or
                  Symbol)
                   <size> is the point size (defaults to 12 if not
                  specified)
                   <s> is `i` if <slant>=="italic" `o` if
                  <slant>=="oblique" `r` otherwise
                   <weight> is `medium` or `bold` if explicitly
                  requested, otherwise `*`
                   <encoding> is set based on the current character set
                  (see `set encoding`).
                  So [1mset term x11 font "arial,15,italic" [22mwill be trans-
                  lated to -*-arial-*-i-*-*-15-*-*-*-*-*-iso8859-1
                  (assuming default encoding).  The <size>, <slant>,
                  and <weight> specifications are all optional.  If you
                  do not specify <slant> or <weight> then you will get
                  whatever font variant the font server offers first.
                  You may set a default enconding via the corresponding
                  X11 resource. E.g.
                        gnuplot*encoding: iso8859-15
                  The driver also recognizes some common PostScript
                  font names and replaces them with possible X11 or
                  TrueType equivalents.  This same sequence is used to
                  process font requests from [1mset label[22m.

                  If your gnuplot was built with configuration option
                  --enable-x11-mbfonts, you can specify multi-byte
                  fonts by using the prefix "mbfont:" on the font name.
                  An additional font may be given, separated by a










   GNUPLOT 4.1                                                      361


                  semicolon.  Since multi-byte font encodings are
                  interpreted according to the locale setting, you must
                  make sure that the environmental variable LC_CTYPE is
                  set to some appropriate locale value such as
                  ja_JP.eucJP, ko_KR.EUC, or zh_CN.EUC.

                  Example:
                        set term x11 font 'mbfont:kana14;k14'
                              # 'kana14' and 'k14' are Japanese X11
                  font aliases, and ';'
                              # is the separator of font names.
                        set term x11 font 'mbfont:fixed,16,r,medium'
                              # <font>,<size>,<slant>,<weight> form is
                  also usable.
                        set title '(mb strings)' font 'mbfont:*-fixed-
                  medium-r-normal--14-*'

                  The same syntax applies to the default font in Xre-
                  sources settings, for example,
                        gnuplot*font: \
                            mbfont:-misc-fixed-medium-r-nor-
                  mal--14-*-*-*-c-*-jisx0208.1983-0

                  If gnuplot is built with --enable-x11-mbfonts, you
                  can use two special PostScript font names 'Ryumin-
                  Light-*' and 'GothicBBB-Medium-*' (standard Japanese
                  PS fonts) without the prefix "mbfont:".




                  [1m95.72.2.  Command-line_options[0m


                  In addition to the X Toolkit options, the following
                  options may be specified on the command line when
                  starting [1mgnuplot [22mor as resources in your ".Xdefaults"
                  file (note that [1mraise [22mand [1mpersist [22mcan be overridden
                  later by [1mset term x11 [no]raise [no]persist)[22m:
























   GNUPLOT 4.1                                                      362


   +-----------------------------------------------------------------------------+
   |  `-mono`      forces monochrome rendering on color displays.                |
   |  `-gray`      requests grayscale rendering on grayscale or color displays.  |
   |               (Grayscale displays receive monochrome rendering by default.) |
   |  `-clear`     requests that the window be cleared momentarily before a      |
   |               new plot is displayed.                                        |
   |  `-tvtwm`     requests that geometry specifications for position of the     |
   |               window be made relative to the currently displayed portion    |
   |               of the virtual root.                                          |
   |  `-raise`     raises plot window after each plot                            |
   | `-noraise`    does not raise plot window after each plot                    |
   |`-novevents`   does not process mouse and key events                         |
   |  `-ctrlq`     closes window on ctrl-q rather than q                         |
   | `-persist`    plot windows survive after main gnuplot program exits         |
   +-----------------------------------------------------------------------------+


   The options are shown above in their command-line syntax.  When
   entered as resources in ".Xdefaults", they require a different syn-
   tax.

   Example:
         gnuplot*gray:  on
         gnuplot*ctrlq: on

   [1mgnuplot [22malso provides a command line option ([1m-pointsize <v>[22m) and a
   resource, [1mgnuplot*pointsize: <v>[22m, to control the size of points
   plotted with the [1mpoints [22mplotting style.  The value [1mv [22mis a real num-
   ber (greater than 0 and less than or equal to ten) used as a scaling
   factor for point sizes.  For example, [1m-pointsize 2 [22muses points twice
   the default size, and [1m-pointsize 0.5 [22muses points half the normal
   size.

   The [1m-noevents [22mswitch disables all mouse and key event processing
   (except for [1mq [22mand [1m<space> [22mfor closing the window). This is useful
   for programs which use the x11 driver independent of the gnuplot
   main program.

   The [1m-ctrlq [22mswitch changes the hot-key that closes a plot window from
   [1mq [22mto [1m<ctrl>q[22m. This is useful is you are using the keystroke-capture
   feature [1mpause mouse keystroke[22m, since it allows the character [1mq [22mto be
   captured just as all other alphanumeric characters. The [1m-ctrlq[0m
   switch similarly replaces the <space> hot-key with <ctrl><space> for
   the same reason.




                  [1m95.72.3.  Monochrome_options[0m


                  For monochrome displays, [1mgnuplot [22mdoes not honor fore-
                  ground or background colors.  The default is black-










   GNUPLOT 4.1                                                      363


                  on-white.  [1m-rv [22mor [1mgnuplot*reverseVideo: on [22mrequests
                  white-on-black.




                  [1m95.72.4.  Color_resources[0m


                  The X11 terminal honors the following resources
                  (shown here with their default values) or the
                  greyscale resources.  The values may be color names
                  as listed in the X11 rgb.txt file on your system,
                  hexadecimal RGB color specifications (see X11 docu-
                  mentation), or a color name followed by a comma and
                  an [1mintensity [22mvalue from 0 to 1.  For example, [1mblue,[0m
                  [1m0.5 [22mmeans a half intensity blue.



                    +--------------------------------+
                    |    gnuplot*background: white   |
                    |    gnuplot*textColor: black    |
                    |    gnuplot*borderColor: black  |
                    |    gnuplot*axisColor: black    |
                    |    gnuplot*line1Color: red     |
                    |    gnuplot*line2Color: green   |
                    |    gnuplot*line3Color: blue    |
                    |    gnuplot*line4Color: magenta |
                    |    gnuplot*line5Color: cyan    |
                    |    gnuplot*line6Color: sienna  |
                    |    gnuplot*line7Color: orange  |
                    |    gnuplot*line8Color: coral   |
                    +--------------------------------+



   The command-line syntax for these is simple only for background,
   which maps directly to the usual X11 toolkit option "-bg".  All oth-
   ers can only be set on the command line by use of the generic "-xrm"
   resource override option

   Examples:

         gnuplot -background coral
   to change the background color.

         gnuplot -xrm 'gnuplot*line1Color:blue'
   to override the first linetype color.














   GNUPLOT 4.1                                                      364


                  [1m95.72.5.  Grayscale_resources[0m


                  When [1m-gray [22mis selected, [1mgnuplot [22mhonors the following
                  resources for grayscale or color displays (shown here
                  with their default values).  Note that the default
                  background is black.



                     +-------------------------------+
                     |    gnuplot*background: black  |
                     |    gnuplot*textGray: white    |
                     |    gnuplot*borderGray: gray50 |
                     |    gnuplot*axisGray: gray50   |
                     |    gnuplot*line1Gray: gray100 |
                     |    gnuplot*line2Gray: gray60  |
                     |    gnuplot*line3Gray: gray80  |
                     |    gnuplot*line4Gray: gray40  |
                     |    gnuplot*line5Gray: gray90  |
                     |    gnuplot*line6Gray: gray50  |
                     |    gnuplot*line7Gray: gray70  |
                     |    gnuplot*line8Gray: gray30  |
                     +-------------------------------+






                  [1m95.72.6.  Line_resources[0m


                  [1mgnuplot [22mhonors the following resources for setting
                  the width (in pixels) of plot lines (shown here with
                  their default values.)  0 or 1 means a minimal width
                  line of 1 pixel width.  A value of 2 or 3 may improve
                  the appearance of some plots.

























   GNUPLOT 4.1                                                      365


                       +---------------------------+
                       |    gnuplot*borderWidth: 2 |
                       |    gnuplot*axisWidth: 0   |
                       |    gnuplot*line1Width: 0  |
                       |    gnuplot*line2Width: 0  |
                       |    gnuplot*line3Width: 0  |
                       |    gnuplot*line4Width: 0  |
                       |    gnuplot*line5Width: 0  |
                       |    gnuplot*line6Width: 0  |
                       |    gnuplot*line7Width: 0  |
                       |    gnuplot*line8Width: 0  |
                       +---------------------------+



   [1mgnuplot [22mhonors the following resources for setting the dash style
   used for plotting lines.  0 means a solid line.  A two-digit number
   [1mjk [22m([1mj [22mand [1mk [22mare >= 1 and <= 9) means a dashed line with a repeated
   pattern of [1mj [22mpixels on followed by [1mk [22mpixels off.  For example, '16'
   is a dotted line with one pixel on followed by six pixels off.  More
   elaborate on/off patterns can be specified with a four-digit value.
   For example, '4441' is four on, four off, four on, one off.  The
   default values shown below are for monochrome displays or monochrome
   rendering on color or grayscale displays.  Color displays default to
   dashed:off



                     +------------------------------+
                     |    gnuplot*dashed: off       |
                     |    gnuplot*borderDashes: 0   |
                     |    gnuplot*axisDashes: 16    |
                     |    gnuplot*line1Dashes: 0    |
                     |    gnuplot*line2Dashes: 42   |
                     |    gnuplot*line3Dashes: 13   |
                     |    gnuplot*line4Dashes: 44   |
                     |    gnuplot*line5Dashes: 15   |
                     |    gnuplot*line6Dashes: 4441 |
                     |    gnuplot*line7Dashes: 42   |
                     |    gnuplot*line8Dashes: 13   |
                     +------------------------------+






                  [1m95.72.7.  X11 pm3d_resources[0m


                  Choosing the appropriate visual class and number of
                  colors is a crucial point in X11 applications and a
                  bit awkward, since X11 supports six visual types in










   GNUPLOT 4.1                                                      366


                  different depths.

                  By default [1mgnuplot [22muses the default visual of the
                  screen. The number of colors which can be allocated
                  depends on the visual class chosen. On a visual class
                  with a depth > 12bit, gnuplot starts with a maximal
                  number of 0x200 colors.  On a visual class with a
                  depth > 8bit (but <= 12 bit) the maximal number of
                  colors is 0x100, on <= 8bit displays the maximum num-
                  ber of colors is 240 (16 are left for line colors).

                  Gnuplot first starts to allocate the maximal number
                  of colors as stated above.  If this fails, the number
                  of colors is reduced by the factor 2 until gnuplot
                  gets all colors which are requested. If dividing [1mmax-[0m
                  [1mcolors [22mby 2 repeatedly results in a number which is
                  smaller than [1mmincolors gnuplot [22mtries to install a
                  private colormap. In this case the window manager is
                  responsible for swapping colormaps when the pointer
                  is moved in and out the x11 driver's window.

                  The default for [1mmincolors [22mis maxcolors / (num_col-
                  ormaps > 1 ? 2 : 8), where num_colormaps is the num-
                  ber of colormaps which are currently used by gnuplot
                  (usually 1, if only one x11 window is open).

                  Some systems support multiple (different) visual
                  classes together on one screen. On these systems it
                  might be necessary to force gnuplot to use a specific
                  visual class, e.g. the default visual might be 8bit
                  PseudoColor but the screen would also support 24bit
                  TrueColor which would be the preferred choice.

                  The information about an Xserver's capabilities can
                  be obtained with the program [1mxdpyinfo[22m.  For the
                  visual names below you can choose one of StaticGray,
                  GrayScale, StaticColor, PseudoColor, TrueColor,
                  DirectColor.  If an Xserver supports a requested
                  visual type at different depths, [1mgnuplot [22mchooses the
                  visual class with the highest depth (deepest).  If
                  the requested visual class matches the default visual
                  and multiple classes of this type are supported, the
                  default visual is preferred.

                  Example: on an 8bit PseudoColor visual you can force
                  a private color map by specifying [1mgnuplot*maxcolors:[0m
                  [1m240 [22mand [1mgnuplot*mincolors: 240[22m.
















   GNUPLOT 4.1                                                      367


                +-----------------------------------------+
                |    gnuplot*maxcolors:  <integer number> |
                |    gnuplot*mincolors:  <integer number> |
                |    gnuplot*visual:     <visual name>    |
                +-----------------------------------------+






                  [1m95.72.8.  X11 other_resources[0m


                  By default the contents of the current plot window
                  are exported to the X11 clipboard in response to X
                  events in the window. Setting the resource 'gnu-
                  plot*exportselection' to 'off' or 'false' will dis-
                  able this.

                  By default text rotation is done using a method that
                  is fast, but can corrupt nearby colors depending on
                  the background.  If this is a problem, you can set
                  the resource 'gnuplot.fastrotate' to 'off'




                   +----------------------------------+
                   |    gnuplot*exportselection:  off |
                   |    gnuplot*fastrotate:  on       |
                   |    gnuplot*ctrlq:  off           |
                   +----------------------------------+





             [1m95.73.  Xlib[0m


             The [1mxlib [22mterminal driver supports the X11 Windows System.
             It generates gnuplot_x11 commands, but sends them to the
             output file specified by [1mset output '<filename>'[22m. [1mset term[0m
             [1mx11 [22mis equivalent to [1mset output "|gnuplot_x11 -noevents";[0m
             [1mset term xlib[22m.  [1mxlib [22mtakes the same set of options as [1mx11[22m.

















   GNUPLOT 4.1                                                      368


             [1m96.  Bugs[0m


             Please e-mail bug reports to the gnuplot-bugs mailing list
             or upload the report to the gnuplot web site on Source-
             Forge.  Please give complete information on the version of
             gnuplot you are using and, if possible, a test script that
             demonstrates the bug.  See [1mseeking-assistance[22m.




             [1m97.  Known limitations[0m


             It is not possible to use in-line data (e.g. plot '-' ...)
             inside the curly brackets of a [1mdo [22mor [1mwhile [22mloop.

             The layout and positioning of the plot key is inaccurate
             whenever superscripts, subscripts, or explicit fonts are
             used in the key text.  (Fixed in 4.7)

             Floating point exceptions (floating point number too
             large/small, divide by zero, etc.) may occasionally be
             generated by user defined functions.  Some of the demos in
             particular may cause numbers to exceed the floating point
             range.  Whether the system ignores such exceptions (in
             which case [1mgnuplot [22mlabels the corresponding point as unde-
             fined) or aborts [1mgnuplot [22mdepends on the compiler/runtime
             environment.

             The gamma, bessel, and erf functions do not work for com-
             plex arguments.

             Coordinates specified as "time" wrap at 24 hours.

             The 'nohidden3d' option that is supposed to exempt indi-
             vidual plots from the global property 'set hidden3d' does
             not work for parametric curves.

             X11 terminal: It is difficult to select UTF-8 fonts.  The
             program does not track the true aspect ratio of the x11
             terminal window.  In order for commands such as "set size
             ratio" to work, the x11 window must itself have equal
             height and width.  Only one color palette at a time is
             active for any given x11 plot window.  This means that
             multiplots whose constituent plots use different palettes
             will not display correctly in x11.

             Qt terminal: If the local qt environment does not support
             "opengl" as a rendering mode then display of polygons and
             surfaces can be very slow.











   GNUPLOT 4.1                                                      369


             [1m98.  External libraries[0m


             External library GD (used by PNG/JPEG/GIF drivers): Ver-
             sions of libgd through 2.0.33 contain various bugs in map-
             ping the characters of Adobe's Symbol font.  Also it is
             possible to trigger a library segfault if an anti-aliased
             line crosses an upper corner of the canvas.

             External library PDFlib (used by PDF driver): Gnuplot can
             be linked against libpdf versions 4, 5, or 6. However,
             these versions differ in their handling of piped I/O.
             Therefore gnuplot scripts using piped output to PDF may
             work only for some versions of PDFlib.

             External library svgalib (used by linux and vgagl driver):
             Requires gnuplot to be suid root (bad!) and has many bugs
             that are specific to the video card or graphics driver
             used in X11.

             Internationalization (locale settings): Gnuplot uses the C
             runtime library routine setlocale() to control locale-spe-
             cific formatting of input and output number, times, and
             date strings.  The locales available, and the level of
             support for locale features such as "thousands' grouping
             separator", depend on the internationalization support
             provided by your individual machine.




































   GNUPLOT 4.1                                                        i



                                 [1mTable of Contents[0m


             Gnuplot  . . . . . . . . . . . . . . . . . . . . . . .   1
             Copyright  . . . . . . . . . . . . . . . . . . . . . .   1
             Introduction . . . . . . . . . . . . . . . . . . . . .   2
             Seeking-assistance . . . . . . . . . . . . . . . . . .   4
             New features . . . . . . . . . . . . . . . . . . . . .   4
             New syntax . . . . . . . . . . . . . . . . . . . . . .   5
             Local customization of linetypes . . . . . . . . . . .   5
             New plot styles  . . . . . . . . . . . . . . . . . . .   5
             Revised polar axes . . . . . . . . . . . . . . . . . .   6
             New smoothing algorithms . . . . . . . . . . . . . . .   6
             New time/date handling . . . . . . . . . . . . . . . .   6
             Statistical summary of data  . . . . . . . . . . . . .   6
             New or revised terminal drivers  . . . . . . . . . . .   6
             Backwards compatibility  . . . . . . . . . . . . . . .   8
             Batch/Interactive Operation  . . . . . . . . . . . . .   8
             Canvas size  . . . . . . . . . . . . . . . . . . . . .   9
             Command-line-editing . . . . . . . . . . . . . . . . .  10
             Comments . . . . . . . . . . . . . . . . . . . . . . .  11
             Coordinates  . . . . . . . . . . . . . . . . . . . . .  11
             Datastrings  . . . . . . . . . . . . . . . . . . . . .  12
             Enhanced text mode . . . . . . . . . . . . . . . . . .  13
             Environment  . . . . . . . . . . . . . . . . . . . . .  14
             Expressions  . . . . . . . . . . . . . . . . . . . . .  15
             Functions  . . . . . . . . . . . . . . . . . . . . . .  16
             Elliptic integrals . . . . . . . . . . . . . . . . . .  19
             Random number generator  . . . . . . . . . . . . . . .  20
             Value  . . . . . . . . . . . . . . . . . . . . . . . .  20
             Operators  . . . . . . . . . . . . . . . . . . . . . .  21
             Unary  . . . . . . . . . . . . . . . . . . . . . . . .  21
             Binary . . . . . . . . . . . . . . . . . . . . . . . .  22
             Ternary  . . . . . . . . . . . . . . . . . . . . . . .  23
             Summation  . . . . . . . . . . . . . . . . . . . . . .  24
             Gnuplot-defined variables  . . . . . . . . . . . . . .  24
             User-defined variables and functions . . . . . . . . .  25
             Fonts  . . . . . . . . . . . . . . . . . . . . . . . .  26
             Cairo (pdfcairo, pngcairo, epscairo, wxt terminals)  .  26
             Gd (png, gif, jpeg terminals)  . . . . . . . . . . . .  27
             Postscript  (also encapsulated postscript *.eps) . . .  27
             Glossary . . . . . . . . . . . . . . . . . . . . . . .  28
             Linetypes, colors, and styles  . . . . . . . . . . . .  29
             Colorspec  . . . . . . . . . . . . . . . . . . . . . .  30
             Background color . . . . . . . . . . . . . . . . . . .  31
             Linecolor variable . . . . . . . . . . . . . . . . . .  32
             Rgbcolor variable  . . . . . . . . . . . . . . . . . .  32
             Linestyles vs linetypes  . . . . . . . . . . . . . . .  33
             Mouse input  . . . . . . . . . . . . . . . . . . . . .  33
             Bind . . . . . . . . . . . . . . . . . . . . . . . . .  34
             Bind space . . . . . . . . . . . . . . . . . . . . . .  35
             Mouse variables  . . . . . . . . . . . . . . . . . . .  36










   GNUPLOT 4.1                                                       ii


             Plotting . . . . . . . . . . . . . . . . . . . . . . .  36
             Start-up (initialization)  . . . . . . . . . . . . . .  37
             String constants and string variables  . . . . . . . .  38
             Substitution and Command line macros . . . . . . . . .  39
             Substitution of system commands in backquotes  . . . .  39
             Substitution of string variables as macros . . . . . .  39
             String variables, macros, and command line substitution . 40
             Syntax . . . . . . . . . . . . . . . . . . . . . . . .  41
             Quote Marks  . . . . . . . . . . . . . . . . . . . . .  42
             Time/Date data . . . . . . . . . . . . . . . . . . . .  43
             Plotting styles  . . . . . . . . . . . . . . . . . . .  44
             Boxerrorbars . . . . . . . . . . . . . . . . . . . . .  45
             Boxes  . . . . . . . . . . . . . . . . . . . . . . . .  45
             Boxplot  . . . . . . . . . . . . . . . . . . . . . . .  47
             Boxxyerrorbars . . . . . . . . . . . . . . . . . . . .  48
             Candlesticks . . . . . . . . . . . . . . . . . . . . .  48
             Circles  . . . . . . . . . . . . . . . . . . . . . . .  49
             Ellipses . . . . . . . . . . . . . . . . . . . . . . .  50
             Dots . . . . . . . . . . . . . . . . . . . . . . . . .  51
             Filledcurves . . . . . . . . . . . . . . . . . . . . .  52
             Financebars  . . . . . . . . . . . . . . . . . . . . .  53
             Fsteps . . . . . . . . . . . . . . . . . . . . . . . .  53
             Fillsteps  . . . . . . . . . . . . . . . . . . . . . .  54
             Histeps  . . . . . . . . . . . . . . . . . . . . . . .  54
             Histograms . . . . . . . . . . . . . . . . . . . . . .  54
             Newhistogram . . . . . . . . . . . . . . . . . . . . .  57
             Automated iteration over multiple columns  . . . . . .  58
             Image  . . . . . . . . . . . . . . . . . . . . . . . .  58
             Transparency . . . . . . . . . . . . . . . . . . . . .  59
             Image failsafe . . . . . . . . . . . . . . . . . . . .  60
             Impulses . . . . . . . . . . . . . . . . . . . . . . .  60
             Labels . . . . . . . . . . . . . . . . . . . . . . . .  60
             Lines  . . . . . . . . . . . . . . . . . . . . . . . .  61
             Linespoints  . . . . . . . . . . . . . . . . . . . . .  61
             Points . . . . . . . . . . . . . . . . . . . . . . . .  62
             Polar  . . . . . . . . . . . . . . . . . . . . . . . .  62
             Steps  . . . . . . . . . . . . . . . . . . . . . . . .  62
             Rgbalpha . . . . . . . . . . . . . . . . . . . . . . .  62
             Rgbimage . . . . . . . . . . . . . . . . . . . . . . .  63
             Vectors  . . . . . . . . . . . . . . . . . . . . . . .  63
             Xerrorbars . . . . . . . . . . . . . . . . . . . . . .  63
             Xyerrorbars  . . . . . . . . . . . . . . . . . . . . .  64
             Yerrorbars . . . . . . . . . . . . . . . . . . . . . .  64
             Xerrorlines  . . . . . . . . . . . . . . . . . . . . .  65
             Xyerrorlines . . . . . . . . . . . . . . . . . . . . .  65
             Yerrorlines  . . . . . . . . . . . . . . . . . . . . .  66
             3D (surface) plots . . . . . . . . . . . . . . . . . .  66
             2D projection (set view map) . . . . . . . . . . . . .  66
             Commands . . . . . . . . . . . . . . . . . . . . . . .  67
             Cd . . . . . . . . . . . . . . . . . . . . . . . . . .  67
             Call . . . . . . . . . . . . . . . . . . . . . . . . .  68
             Clear  . . . . . . . . . . . . . . . . . . . . . . . .  68
             Do . . . . . . . . . . . . . . . . . . . . . . . . . .  69










   =1 .if 0 .tl 'GNUPLOT 4.1''%'


             Evaluate . . . . . . . . . . . . . . . . . . . . . . .  69
             Exit . . . . . . . . . . . . . . . . . . . . . . . . .  70
             Fit  . . . . . . . . . . . . . . . . . . . . . . . . .  70
             Adjustable parameters  . . . . . . . . . . . . . . . .  73
             Short introduction . . . . . . . . . . . . . . . . . .  73
             Error estimates  . . . . . . . . . . . . . . . . . . .  75
             Statistical overview . . . . . . . . . . . . . . . . .  75
             Practical guidelines . . . . . . . . . . . . . . . . .  77
             Control  . . . . . . . . . . . . . . . . . . . . . . .  78
             Control variables  . . . . . . . . . . . . . . . . . .  78
             Environment variables  . . . . . . . . . . . . . . . .  79
             Multi-branch . . . . . . . . . . . . . . . . . . . . .  80
             Starting values  . . . . . . . . . . . . . . . . . . .  80
             Tips . . . . . . . . . . . . . . . . . . . . . . . . .  81
             Help . . . . . . . . . . . . . . . . . . . . . . . . .  82
             History  . . . . . . . . . . . . . . . . . . . . . . .  83
             If . . . . . . . . . . . . . . . . . . . . . . . . . .  83
             If-old . . . . . . . . . . . . . . . . . . . . . . . .  84
             Iteration  . . . . . . . . . . . . . . . . . . . . . .  85
             Load . . . . . . . . . . . . . . . . . . . . . . . . .  85
             Lower  . . . . . . . . . . . . . . . . . . . . . . . .  86
             Pause  . . . . . . . . . . . . . . . . . . . . . . . .  86
             Plot . . . . . . . . . . . . . . . . . . . . . . . . .  88
             Axes . . . . . . . . . . . . . . . . . . . . . . . . .  89
             Binary . . . . . . . . . . . . . . . . . . . . . . . .  89
             General  . . . . . . . . . . . . . . . . . . . . . . .  90
             Array  . . . . . . . . . . . . . . . . . . . . . . . .  91
             Record . . . . . . . . . . . . . . . . . . . . . . . .  92
             Skip . . . . . . . . . . . . . . . . . . . . . . . . .  92
             Format . . . . . . . . . . . . . . . . . . . . . . . .  92
             Endian . . . . . . . . . . . . . . . . . . . . . . . .  93
             Filetype . . . . . . . . . . . . . . . . . . . . . . .  93
             Avs  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Edf  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Png  . . . . . . . . . . . . . . . . . . . . . . . . .  94
             Keywords . . . . . . . . . . . . . . . . . . . . . . .  95
             Scan . . . . . . . . . . . . . . . . . . . . . . . . .  95
             Transpose  . . . . . . . . . . . . . . . . . . . . . .  95
             Dx, dy, dz . . . . . . . . . . . . . . . . . . . . . .  96
             Flipx, flipy, flipz  . . . . . . . . . . . . . . . . .  96
             Origin . . . . . . . . . . . . . . . . . . . . . . . .  96
             Center . . . . . . . . . . . . . . . . . . . . . . . .  97
             Rotate . . . . . . . . . . . . . . . . . . . . . . . .  97
             Perpendicular  . . . . . . . . . . . . . . . . . . . .  97
             Data . . . . . . . . . . . . . . . . . . . . . . . . .  98
             Every  . . . . . . . . . . . . . . . . . . . . . . . . 100
             Example datafile . . . . . . . . . . . . . . . . . . . 101
             Index  . . . . . . . . . . . . . . . . . . . . . . . . 102
             Smooth . . . . . . . . . . . . . . . . . . . . . . . . 103
             Acsplines  . . . . . . . . . . . . . . . . . . . . . . 104
             Bezier . . . . . . . . . . . . . . . . . . . . . . . . 105
             Csplines . . . . . . . . . . . . . . . . . . . . . . . 105
             Sbezier  . . . . . . . . . . . . . . . . . . . . . . . 105










   GNUPLOT 4.1                                                       iv


             Unique . . . . . . . . . . . . . . . . . . . . . . . . 105
             Frequency  . . . . . . . . . . . . . . . . . . . . . . 105
             Cumulative . . . . . . . . . . . . . . . . . . . . . . 106
             Cnormal  . . . . . . . . . . . . . . . . . . . . . . . 106
             Kdensity . . . . . . . . . . . . . . . . . . . . . . . 106
             Special-filenames  . . . . . . . . . . . . . . . . . . 107
             Thru . . . . . . . . . . . . . . . . . . . . . . . . . 109
             Using  . . . . . . . . . . . . . . . . . . . . . . . . 110
             Using_examples . . . . . . . . . . . . . . . . . . . . 111
             Pseudocolumns  . . . . . . . . . . . . . . . . . . . . 113
             Xticlabels . . . . . . . . . . . . . . . . . . . . . . 113
             X2ticlabels  . . . . . . . . . . . . . . . . . . . . . 114
             Yticlabels . . . . . . . . . . . . . . . . . . . . . . 114
             Y2ticlabels  . . . . . . . . . . . . . . . . . . . . . 115
             Zticlabels . . . . . . . . . . . . . . . . . . . . . . 115
             Volatile . . . . . . . . . . . . . . . . . . . . . . . 115
             Errorbars  . . . . . . . . . . . . . . . . . . . . . . 115
             Errorlines . . . . . . . . . . . . . . . . . . . . . . 116
             Functions  . . . . . . . . . . . . . . . . . . . . . . 117
             Parametric . . . . . . . . . . . . . . . . . . . . . . 117
             Ranges . . . . . . . . . . . . . . . . . . . . . . . . 118
             Iteration  . . . . . . . . . . . . . . . . . . . . . . 120
             Title  . . . . . . . . . . . . . . . . . . . . . . . . 121
             With . . . . . . . . . . . . . . . . . . . . . . . . . 122
             Print  . . . . . . . . . . . . . . . . . . . . . . . . 125
             Pwd  . . . . . . . . . . . . . . . . . . . . . . . . . 126
             Quit . . . . . . . . . . . . . . . . . . . . . . . . . 126
             Raise  . . . . . . . . . . . . . . . . . . . . . . . . 126
             Refresh  . . . . . . . . . . . . . . . . . . . . . . . 127
             Replot . . . . . . . . . . . . . . . . . . . . . . . . 127
             Reread . . . . . . . . . . . . . . . . . . . . . . . . 128
             Reset  . . . . . . . . . . . . . . . . . . . . . . . . 129
             Save . . . . . . . . . . . . . . . . . . . . . . . . . 129
             Set-show . . . . . . . . . . . . . . . . . . . . . . . 130
             Angles . . . . . . . . . . . . . . . . . . . . . . . . 130
             Arrow  . . . . . . . . . . . . . . . . . . . . . . . . 131
             Autoscale  . . . . . . . . . . . . . . . . . . . . . . 134
             Parametric mode  . . . . . . . . . . . . . . . . . . . 136
             Polar mode . . . . . . . . . . . . . . . . . . . . . . 137
             Bars . . . . . . . . . . . . . . . . . . . . . . . . . 137
             Bind . . . . . . . . . . . . . . . . . . . . . . . . . 137
             Bmargin  . . . . . . . . . . . . . . . . . . . . . . . 138
             Border . . . . . . . . . . . . . . . . . . . . . . . . 138
             Boxwidth . . . . . . . . . . . . . . . . . . . . . . . 140
             Clabel . . . . . . . . . . . . . . . . . . . . . . . . 141
             Clip . . . . . . . . . . . . . . . . . . . . . . . . . 141
             Cntrparam  . . . . . . . . . . . . . . . . . . . . . . 142
             Color box  . . . . . . . . . . . . . . . . . . . . . . 144
             Colornames . . . . . . . . . . . . . . . . . . . . . . 146
             Contour  . . . . . . . . . . . . . . . . . . . . . . . 146
             Data style . . . . . . . . . . . . . . . . . . . . . . 147
             Datafile . . . . . . . . . . . . . . . . . . . . . . . 147
             Set datafile fortran . . . . . . . . . . . . . . . . . 147










   GNUPLOT 4.1                                                        v


             Set datafile nofpe_trap  . . . . . . . . . . . . . . . 148
             Set datafile missing . . . . . . . . . . . . . . . . . 148
             Set datafile separator . . . . . . . . . . . . . . . . 149
             Set datafile commentschars . . . . . . . . . . . . . . 150
             Set datafile binary  . . . . . . . . . . . . . . . . . 150
             Decimalsign  . . . . . . . . . . . . . . . . . . . . . 151
             Dgrid3d  . . . . . . . . . . . . . . . . . . . . . . . 152
             Dummy  . . . . . . . . . . . . . . . . . . . . . . . . 154
             Encoding . . . . . . . . . . . . . . . . . . . . . . . 155
             Fit  . . . . . . . . . . . . . . . . . . . . . . . . . 156
             Fontpath . . . . . . . . . . . . . . . . . . . . . . . 157
             Format . . . . . . . . . . . . . . . . . . . . . . . . 158
             Gprintf  . . . . . . . . . . . . . . . . . . . . . . . 158
             Format specifiers  . . . . . . . . . . . . . . . . . . 159
             Time/date specifiers . . . . . . . . . . . . . . . . . 160
             Function style . . . . . . . . . . . . . . . . . . . . 162
             Functions  . . . . . . . . . . . . . . . . . . . . . . 162
             Grid . . . . . . . . . . . . . . . . . . . . . . . . . 162
             Hidden3d . . . . . . . . . . . . . . . . . . . . . . . 163
             Historysize  . . . . . . . . . . . . . . . . . . . . . 166
             Isosamples . . . . . . . . . . . . . . . . . . . . . . 167
             Key  . . . . . . . . . . . . . . . . . . . . . . . . . 167
             Key placement  . . . . . . . . . . . . . . . . . . . . 171
             Key samples  . . . . . . . . . . . . . . . . . . . . . 172
             Label  . . . . . . . . . . . . . . . . . . . . . . . . 173
             Linetype . . . . . . . . . . . . . . . . . . . . . . . 176
             Lmargin  . . . . . . . . . . . . . . . . . . . . . . . 177
             Loadpath . . . . . . . . . . . . . . . . . . . . . . . 177
             Locale . . . . . . . . . . . . . . . . . . . . . . . . 178
             Logscale . . . . . . . . . . . . . . . . . . . . . . . 178
             Macros . . . . . . . . . . . . . . . . . . . . . . . . 179
             Mapping  . . . . . . . . . . . . . . . . . . . . . . . 179
             Margin . . . . . . . . . . . . . . . . . . . . . . . . 180
             Mouse  . . . . . . . . . . . . . . . . . . . . . . . . 181
             Doubleclick  . . . . . . . . . . . . . . . . . . . . . 183
             Mouseformat  . . . . . . . . . . . . . . . . . . . . . 183
             Scrolling  . . . . . . . . . . . . . . . . . . . . . . 184
             X11 mouse  . . . . . . . . . . . . . . . . . . . . . . 184
             Zoom . . . . . . . . . . . . . . . . . . . . . . . . . 184
             Multiplot  . . . . . . . . . . . . . . . . . . . . . . 185
             Mx2tics  . . . . . . . . . . . . . . . . . . . . . . . 187
             Mxtics . . . . . . . . . . . . . . . . . . . . . . . . 187
             My2tics  . . . . . . . . . . . . . . . . . . . . . . . 188
             Mytics . . . . . . . . . . . . . . . . . . . . . . . . 188
             Mztics . . . . . . . . . . . . . . . . . . . . . . . . 188
             Object . . . . . . . . . . . . . . . . . . . . . . . . 188
             Rectangle  . . . . . . . . . . . . . . . . . . . . . . 189
             Ellipse  . . . . . . . . . . . . . . . . . . . . . . . 190
             Circle . . . . . . . . . . . . . . . . . . . . . . . . 191
             Polygon  . . . . . . . . . . . . . . . . . . . . . . . 192
             Offsets  . . . . . . . . . . . . . . . . . . . . . . . 192
             Origin . . . . . . . . . . . . . . . . . . . . . . . . 193
             Output . . . . . . . . . . . . . . . . . . . . . . . . 193










   GNUPLOT 4.1                                                       vi


             Parametric . . . . . . . . . . . . . . . . . . . . . . 194
             Plot . . . . . . . . . . . . . . . . . . . . . . . . . 195
             Pm3d . . . . . . . . . . . . . . . . . . . . . . . . . 195
             Algorithm  . . . . . . . . . . . . . . . . . . . . . . 196
             Position . . . . . . . . . . . . . . . . . . . . . . . 198
             Scanorder  . . . . . . . . . . . . . . . . . . . . . . 198
             Clipping . . . . . . . . . . . . . . . . . . . . . . . 199
             Color_assignment . . . . . . . . . . . . . . . . . . . 199
             Hidden3d . . . . . . . . . . . . . . . . . . . . . . . 200
             Interpolate  . . . . . . . . . . . . . . . . . . . . . 201
             Deprecated_options . . . . . . . . . . . . . . . . . . 201
             Palette  . . . . . . . . . . . . . . . . . . . . . . . 202
             Rgbformulae  . . . . . . . . . . . . . . . . . . . . . 204
             Defined  . . . . . . . . . . . . . . . . . . . . . . . 205
             Functions  . . . . . . . . . . . . . . . . . . . . . . 207
             Cubehelix  . . . . . . . . . . . . . . . . . . . . . . 207
             File . . . . . . . . . . . . . . . . . . . . . . . . . 208
             Gamma correction . . . . . . . . . . . . . . . . . . . 209
             Postscript . . . . . . . . . . . . . . . . . . . . . . 209
             Pointintervalbox . . . . . . . . . . . . . . . . . . . 210
             Pointsize  . . . . . . . . . . . . . . . . . . . . . . 210
             Polar  . . . . . . . . . . . . . . . . . . . . . . . . 211
             Print  . . . . . . . . . . . . . . . . . . . . . . . . 212
             Psdir  . . . . . . . . . . . . . . . . . . . . . . . . 212
             Raxis  . . . . . . . . . . . . . . . . . . . . . . . . 213
             Rmargin  . . . . . . . . . . . . . . . . . . . . . . . 213
             Rrange . . . . . . . . . . . . . . . . . . . . . . . . 213
             Rtics  . . . . . . . . . . . . . . . . . . . . . . . . 213
             Samples  . . . . . . . . . . . . . . . . . . . . . . . 213
             Size . . . . . . . . . . . . . . . . . . . . . . . . . 214
             Style  . . . . . . . . . . . . . . . . . . . . . . . . 215
             Set style arrow  . . . . . . . . . . . . . . . . . . . 216
             Boxplot  . . . . . . . . . . . . . . . . . . . . . . . 218
             Set style data . . . . . . . . . . . . . . . . . . . . 220
             Set style fill . . . . . . . . . . . . . . . . . . . . 220
             Set style fill transparent . . . . . . . . . . . . . . 221
             Set style function . . . . . . . . . . . . . . . . . . 222
             Set style increment  . . . . . . . . . . . . . . . . . 222
             Set style line . . . . . . . . . . . . . . . . . . . . 223
             Set style circle . . . . . . . . . . . . . . . . . . . 225
             Set style rectangle  . . . . . . . . . . . . . . . . . 225
             Set style ellipse  . . . . . . . . . . . . . . . . . . 226
             Surface  . . . . . . . . . . . . . . . . . . . . . . . 227
             Table  . . . . . . . . . . . . . . . . . . . . . . . . 228
             Terminal . . . . . . . . . . . . . . . . . . . . . . . 228
             Termoption . . . . . . . . . . . . . . . . . . . . . . 229
             Tics . . . . . . . . . . . . . . . . . . . . . . . . . 229
             Ticslevel  . . . . . . . . . . . . . . . . . . . . . . 231
             Ticscale . . . . . . . . . . . . . . . . . . . . . . . 231
             Timestamp  . . . . . . . . . . . . . . . . . . . . . . 231
             Timefmt  . . . . . . . . . . . . . . . . . . . . . . . 232
             Title  . . . . . . . . . . . . . . . . . . . . . . . . 233
             Tmargin  . . . . . . . . . . . . . . . . . . . . . . . 234










   GNUPLOT 4.1                                                      vii


             Trange . . . . . . . . . . . . . . . . . . . . . . . . 234
             Urange . . . . . . . . . . . . . . . . . . . . . . . . 235
             Variables  . . . . . . . . . . . . . . . . . . . . . . 235
             Version  . . . . . . . . . . . . . . . . . . . . . . . 235
             View . . . . . . . . . . . . . . . . . . . . . . . . . 235
             Equal_axes . . . . . . . . . . . . . . . . . . . . . . 236
             Vrange . . . . . . . . . . . . . . . . . . . . . . . . 237
             X2data . . . . . . . . . . . . . . . . . . . . . . . . 237
             X2dtics  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2label  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2mtics  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2range  . . . . . . . . . . . . . . . . . . . . . . . 237
             X2tics . . . . . . . . . . . . . . . . . . . . . . . . 238
             X2zeroaxis . . . . . . . . . . . . . . . . . . . . . . 238
             Xdata  . . . . . . . . . . . . . . . . . . . . . . . . 238
             Xdtics . . . . . . . . . . . . . . . . . . . . . . . . 239
             Xlabel . . . . . . . . . . . . . . . . . . . . . . . . 239
             Xmtics . . . . . . . . . . . . . . . . . . . . . . . . 241
             Xrange . . . . . . . . . . . . . . . . . . . . . . . . 241
             Xtics  . . . . . . . . . . . . . . . . . . . . . . . . 243
             Xtics time_data  . . . . . . . . . . . . . . . . . . . 247
             Xtics rangelimited . . . . . . . . . . . . . . . . . . 247
             Xyplane  . . . . . . . . . . . . . . . . . . . . . . . 248
             Xzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 249
             Y2data . . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2dtics  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2label  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2mtics  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2range  . . . . . . . . . . . . . . . . . . . . . . . 249
             Y2tics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Y2zeroaxis . . . . . . . . . . . . . . . . . . . . . . 250
             Ydata  . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ydtics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ylabel . . . . . . . . . . . . . . . . . . . . . . . . 250
             Ymtics . . . . . . . . . . . . . . . . . . . . . . . . 250
             Yrange . . . . . . . . . . . . . . . . . . . . . . . . 251
             Ytics  . . . . . . . . . . . . . . . . . . . . . . . . 251
             Yzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 251
             Zdata  . . . . . . . . . . . . . . . . . . . . . . . . 251
             Zdtics . . . . . . . . . . . . . . . . . . . . . . . . 251
             Zzeroaxis  . . . . . . . . . . . . . . . . . . . . . . 251
             Cbdata . . . . . . . . . . . . . . . . . . . . . . . . 252
             Cbdtics  . . . . . . . . . . . . . . . . . . . . . . . 252
             Zero . . . . . . . . . . . . . . . . . . . . . . . . . 252
             Zeroaxis . . . . . . . . . . . . . . . . . . . . . . . 252
             Zlabel . . . . . . . . . . . . . . . . . . . . . . . . 253
             Zmtics . . . . . . . . . . . . . . . . . . . . . . . . 253
             Zrange . . . . . . . . . . . . . . . . . . . . . . . . 253
             Ztics  . . . . . . . . . . . . . . . . . . . . . . . . 254
             Cblabel  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbmtics  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbrange  . . . . . . . . . . . . . . . . . . . . . . . 254
             Cbtics . . . . . . . . . . . . . . . . . . . . . . . . 254










   GNUPLOT 4.1                                                     viii


             Shell  . . . . . . . . . . . . . . . . . . . . . . . . 255
             Splot  . . . . . . . . . . . . . . . . . . . . . . . . 255
             Data-file  . . . . . . . . . . . . . . . . . . . . . . 256
             Matrix . . . . . . . . . . . . . . . . . . . . . . . . 257
             Example datafile . . . . . . . . . . . . . . . . . . . 259
             Grid data  . . . . . . . . . . . . . . . . . . . . . . 260
             Splot surfaces . . . . . . . . . . . . . . . . . . . . 261
             Stats (Statistical Summary)  . . . . . . . . . . . . . 261
             System . . . . . . . . . . . . . . . . . . . . . . . . 263
             Test . . . . . . . . . . . . . . . . . . . . . . . . . 263
             Undefine . . . . . . . . . . . . . . . . . . . . . . . 264
             Unset  . . . . . . . . . . . . . . . . . . . . . . . . 264
             Terminal . . . . . . . . . . . . . . . . . . . . . . . 265
             Update . . . . . . . . . . . . . . . . . . . . . . . . 265
             While  . . . . . . . . . . . . . . . . . . . . . . . . 265
             Terminal types . . . . . . . . . . . . . . . . . . . . 266
             Complete list of terminals . . . . . . . . . . . . . . 266
             Aed767 . . . . . . . . . . . . . . . . . . . . . . . . 266
             Aifm . . . . . . . . . . . . . . . . . . . . . . . . . 266
             Aqua . . . . . . . . . . . . . . . . . . . . . . . . . 267
             Be . . . . . . . . . . . . . . . . . . . . . . . . . . 267
             Command-line_options . . . . . . . . . . . . . . . . . 268
             Monochrome_options . . . . . . . . . . . . . . . . . . 269
             Color_resources  . . . . . . . . . . . . . . . . . . . 269
             Grayscale_resources  . . . . . . . . . . . . . . . . . 270
             Line_resources . . . . . . . . . . . . . . . . . . . . 271
             Cairolatex . . . . . . . . . . . . . . . . . . . . . . 272
             Canvas . . . . . . . . . . . . . . . . . . . . . . . . 275
             Cgi  . . . . . . . . . . . . . . . . . . . . . . . . . 277
             Cgm  . . . . . . . . . . . . . . . . . . . . . . . . . 277
             Cgm font . . . . . . . . . . . . . . . . . . . . . . . 278
             Cgm fontsize . . . . . . . . . . . . . . . . . . . . . 280
             Cgm linewidth  . . . . . . . . . . . . . . . . . . . . 280
             Cgm rotate . . . . . . . . . . . . . . . . . . . . . . 280
             Cgm solid  . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm size . . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm width  . . . . . . . . . . . . . . . . . . . . . . 281
             Cgm nofontlist . . . . . . . . . . . . . . . . . . . . 282
             Context  . . . . . . . . . . . . . . . . . . . . . . . 282
             Requirements . . . . . . . . . . . . . . . . . . . . . 285
             Calling gnuplot from ConTeXt . . . . . . . . . . . . . 285
             Corel  . . . . . . . . . . . . . . . . . . . . . . . . 285
             Debug  . . . . . . . . . . . . . . . . . . . . . . . . 286
             Dumb . . . . . . . . . . . . . . . . . . . . . . . . . 286
             Dxf  . . . . . . . . . . . . . . . . . . . . . . . . . 287
             Dxy800a  . . . . . . . . . . . . . . . . . . . . . . . 287
             Eepic  . . . . . . . . . . . . . . . . . . . . . . . . 287
             Emf  . . . . . . . . . . . . . . . . . . . . . . . . . 289
             Emxvga . . . . . . . . . . . . . . . . . . . . . . . . 290
             Epscairo . . . . . . . . . . . . . . . . . . . . . . . 290
             Epslatex . . . . . . . . . . . . . . . . . . . . . . . 290
             Epson_180dpi . . . . . . . . . . . . . . . . . . . . . 295
             Excl . . . . . . . . . . . . . . . . . . . . . . . . . 296










   GNUPLOT 4.1                                                       ix


             Fig  . . . . . . . . . . . . . . . . . . . . . . . . . 296
             Ggi  . . . . . . . . . . . . . . . . . . . . . . . . . 298
             Gif  . . . . . . . . . . . . . . . . . . . . . . . . . 299
             Examples . . . . . . . . . . . . . . . . . . . . . . . 301
             Gpic . . . . . . . . . . . . . . . . . . . . . . . . . 301
             Grass  . . . . . . . . . . . . . . . . . . . . . . . . 302
             Hp2623a  . . . . . . . . . . . . . . . . . . . . . . . 303
             Hp2648 . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hp500c . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hpgl . . . . . . . . . . . . . . . . . . . . . . . . . 303
             Hpljii . . . . . . . . . . . . . . . . . . . . . . . . 305
             Hppj . . . . . . . . . . . . . . . . . . . . . . . . . 305
             Imagen . . . . . . . . . . . . . . . . . . . . . . . . 305
             Jpeg . . . . . . . . . . . . . . . . . . . . . . . . . 306
             Kyo  . . . . . . . . . . . . . . . . . . . . . . . . . 307
             Latex  . . . . . . . . . . . . . . . . . . . . . . . . 307
             Linux  . . . . . . . . . . . . . . . . . . . . . . . . 308
             Lua  . . . . . . . . . . . . . . . . . . . . . . . . . 308
             Lua tikz . . . . . . . . . . . . . . . . . . . . . . . 309
             Macintosh  . . . . . . . . . . . . . . . . . . . . . . 313
             Mf . . . . . . . . . . . . . . . . . . . . . . . . . . 313
             METAFONT Instructions  . . . . . . . . . . . . . . . . 314
             Mif  . . . . . . . . . . . . . . . . . . . . . . . . . 315
             Mp . . . . . . . . . . . . . . . . . . . . . . . . . . 316
             Metapost Instructions  . . . . . . . . . . . . . . . . 319
             Next . . . . . . . . . . . . . . . . . . . . . . . . . 320
             Openstep (next)  . . . . . . . . . . . . . . . . . . . 321
             Pbm  . . . . . . . . . . . . . . . . . . . . . . . . . 321
             Pdf  . . . . . . . . . . . . . . . . . . . . . . . . . 322
             Pdfcairo . . . . . . . . . . . . . . . . . . . . . . . 323
             Pm . . . . . . . . . . . . . . . . . . . . . . . . . . 325
             Png  . . . . . . . . . . . . . . . . . . . . . . . . . 326
             Examples . . . . . . . . . . . . . . . . . . . . . . . 327
             Pngcairo . . . . . . . . . . . . . . . . . . . . . . . 327
             Postscript . . . . . . . . . . . . . . . . . . . . . . 329
             Editing postscript . . . . . . . . . . . . . . . . . . 333
             Postscript fontfile  . . . . . . . . . . . . . . . . . 333
             Postscript prologue  . . . . . . . . . . . . . . . . . 336
             Postscript adobeglyphnames . . . . . . . . . . . . . . 336
             Pslatex and pstex  . . . . . . . . . . . . . . . . . . 336
             Pstricks . . . . . . . . . . . . . . . . . . . . . . . 339
             Qms  . . . . . . . . . . . . . . . . . . . . . . . . . 340
             Qt . . . . . . . . . . . . . . . . . . . . . . . . . . 340
             Regis  . . . . . . . . . . . . . . . . . . . . . . . . 342
             Sun  . . . . . . . . . . . . . . . . . . . . . . . . . 342
             Svg  . . . . . . . . . . . . . . . . . . . . . . . . . 342
             Svga . . . . . . . . . . . . . . . . . . . . . . . . . 344
             Tek40  . . . . . . . . . . . . . . . . . . . . . . . . 344
             Tek410x  . . . . . . . . . . . . . . . . . . . . . . . 344
             Texdraw  . . . . . . . . . . . . . . . . . . . . . . . 344
             Tgif . . . . . . . . . . . . . . . . . . . . . . . . . 345
             Tikz . . . . . . . . . . . . . . . . . . . . . . . . . 346
             Tkcanvas . . . . . . . . . . . . . . . . . . . . . . . 346










   GNUPLOT 4.1                                                        x


             Tpic . . . . . . . . . . . . . . . . . . . . . . . . . 347
             Vgagl  . . . . . . . . . . . . . . . . . . . . . . . . 348
             VWS  . . . . . . . . . . . . . . . . . . . . . . . . . 349
             Vx384  . . . . . . . . . . . . . . . . . . . . . . . . 349
             Windows  . . . . . . . . . . . . . . . . . . . . . . . 349
             Graph-menu . . . . . . . . . . . . . . . . . . . . . . 351
             Printing . . . . . . . . . . . . . . . . . . . . . . . 352
             Text-menu  . . . . . . . . . . . . . . . . . . . . . . 352
             Wgnuplot.mnu . . . . . . . . . . . . . . . . . . . . . 353
             Wgnuplot.ini . . . . . . . . . . . . . . . . . . . . . 354
             Wxt  . . . . . . . . . . . . . . . . . . . . . . . . . 355
             X11  . . . . . . . . . . . . . . . . . . . . . . . . . 358
             X11_fonts  . . . . . . . . . . . . . . . . . . . . . . 360
             Command-line_options . . . . . . . . . . . . . . . . . 361
             Monochrome_options . . . . . . . . . . . . . . . . . . 362
             Color_resources  . . . . . . . . . . . . . . . . . . . 363
             Grayscale_resources  . . . . . . . . . . . . . . . . . 364
             Line_resources . . . . . . . . . . . . . . . . . . . . 364
             X11 pm3d_resources . . . . . . . . . . . . . . . . . . 365
             X11 other_resources  . . . . . . . . . . . . . . . . . 367
             Xlib . . . . . . . . . . . . . . . . . . . . . . . . . 367
             Bugs . . . . . . . . . . . . . . . . . . . . . . . . . 368
             Known limitations  . . . . . . . . . . . . . . . . . . 368
             External libraries . . . . . . . . . . . . . . . . . . 369



































