class GeoRuby::SimpleFeatures::Polygon

Represents a polygon as an array of linear rings (see LinearRing). No check is performed regarding the validity of the geometries forming the polygon.

Attributes

rings[R]

the list of rings forming the polygon

Public Class Methods

from_coordinates(point_sequences,srid=DEFAULT_SRID,with_z=false,with_m=false) click to toggle source

creates a new polygon. Accepts a sequence of points as argument : ((x,y).…(x,y)),((x,y).….(x,y))

# File lib/geo_ruby/simple_features/polygon.rb, line 134
def self.from_coordinates(point_sequences,srid=DEFAULT_SRID,with_z=false,with_m=false)
  polygon = new(srid,with_z,with_m)
  polygon.concat( point_sequences.collect {|points| LinearRing.from_coordinates(points,srid,with_z,with_m) } )
  polygon
end
from_linear_rings(linear_rings,srid = DEFAULT_SRID,with_z=false,with_m=false) click to toggle source

creates a new polygon. Accepts an array of linear strings as argument

# File lib/geo_ruby/simple_features/polygon.rb, line 127
def self.from_linear_rings(linear_rings,srid = DEFAULT_SRID,with_z=false,with_m=false)
  polygon = new(srid,with_z,with_m)
  polygon.concat(linear_rings)
  polygon
end
from_points(point_sequences, srid=DEFAULT_SRID,with_z=false,with_m=false) click to toggle source

creates a new polygon from a list of Points (pt1.…ptn),(pti.…ptj)

# File lib/geo_ruby/simple_features/polygon.rb, line 141
def self.from_points(point_sequences, srid=DEFAULT_SRID,with_z=false,with_m=false)
  polygon = new(srid,with_z,with_m)
  polygon.concat( point_sequences.collect {|points| LinearRing.from_points(points,srid,with_z,with_m) } )
  polygon

end
new(srid = DEFAULT_SRID,with_z=false,with_m=false) click to toggle source
Calls superclass method GeoRuby::SimpleFeatures::Geometry.new
# File lib/geo_ruby/simple_features/polygon.rb, line 10
def initialize(srid = DEFAULT_SRID,with_z=false,with_m=false)
  super(srid,with_z,with_m)
  @rings = []
end

Public Instance Methods

==(other_polygon) click to toggle source

tests for other equality. The SRID is not taken into account.

# File lib/geo_ruby/simple_features/polygon.rb, line 54
def ==(other_polygon)
  if other_polygon.class != self.class or
      length != other_polygon.length
    false
  else
    index=0
    while index<length
      return false if self[index] != other_polygon[index]
      index+=1
    end
    true
  end
end
binary_geometry_type() click to toggle source

WKB geometry type

# File lib/geo_ruby/simple_features/polygon.rb, line 74
def binary_geometry_type
  3
end
binary_representation(allow_z=true,allow_m=true) click to toggle source

binary representation of a polygon, without the headers neccessary for a valid WKB string

# File lib/geo_ruby/simple_features/polygon.rb, line 68
def binary_representation(allow_z=true,allow_m=true)
  rep = [length].pack("V")
  each {|linear_ring| rep << linear_ring.binary_representation(allow_z,allow_m)}
  rep
end
bounding_box() click to toggle source

Bounding box in 2D/3D. Returns an array of 2 points

# File lib/geo_ruby/simple_features/polygon.rb, line 21
def bounding_box
  unless with_z
    @rings[0].bounding_box
  else
    result = @rings[0].bounding_box #valid for x and y

    max_z, min_z = result[1].z, result[0].z
    1.upto(size - 1) do |index|
      bbox = @rings[index].bounding_box
      sw = bbox[0]
      ne = bbox[1]
      max_z = ne.z if ne.z > max_z
      min_z = sw.z if sw.z < min_z 
    end
    result[1].z, result[0].z = max_z, min_z
    result
  end
end
georss_gml_representation(options) click to toggle source

georss gml representation

# File lib/geo_ruby/simple_features/polygon.rb, line 100
def georss_gml_representation(options)
  georss_ns = options[:georss_ns] || "georss"
  gml_ns = options[:gml_ns] || "gml"
 
  result = "<#{georss_ns}:where>\n<#{gml_ns}:Polygon>\n<#{gml_ns}:exterior>\n<#{gml_ns}:LinearRing>\n<#{gml_ns}:posList>\n" + self[0].georss_poslist + "\n</#{gml_ns}:posList>\n</#{gml_ns}:LinearRing>\n</#{gml_ns}:exterior>\n</#{gml_ns}:Polygon>\n</#{georss_ns}:where>\n"
end
georss_simple_representation(options) click to toggle source

georss simple representation : outputs only the outer ring

# File lib/geo_ruby/simple_features/polygon.rb, line 88
def georss_simple_representation(options)
  georss_ns = options[:georss_ns] || "georss"
  geom_attr = options[:geom_attr]
  "<#{georss_ns}:polygon#{geom_attr}>" + self[0].georss_poslist + "</#{georss_ns}:polygon>\n"
end
georss_w3cgeo_representation(options) click to toggle source

georss w3c representation : outputs the first point of the outer ring

# File lib/geo_ruby/simple_features/polygon.rb, line 94
def georss_w3cgeo_representation(options)
  w3cgeo_ns = options[:w3cgeo_ns] || "geo"
  
  "<#{w3cgeo_ns}:lat>#{self[0][0].y}</#{w3cgeo_ns}:lat>\n<#{w3cgeo_ns}:long>#{self[0][0].x}</#{w3cgeo_ns}:long>\n"
end
kml_representation(options = {}) click to toggle source

outputs the geometry in kml format : options are :id, :tesselate, :extrude, :altitude_mode. If the altitude_mode option is not present, the Z (if present) will not be output (since it won't be used by GE anyway: clampToGround is the default)

# File lib/geo_ruby/simple_features/polygon.rb, line 110
def kml_representation(options = {})
  result = "<Polygon#{options[:id_attr]}>\n"
  result += options[:geom_data] if options[:geom_data]
  rings.each_with_index do |ring, i|
    if i == 0
      boundary = "outerBoundaryIs"
    else
      boundary = "innerBoundaryIs"
    end
    result += "<#{boundary}><LinearRing><coordinates>\n"
    result += ring.kml_poslist(options)
    result += "\n</coordinates></LinearRing></#{boundary}>\n"
  end
  result += "</Polygon>\n"
end
m_range() click to toggle source
# File lib/geo_ruby/simple_features/polygon.rb, line 39
def m_range
  if with_m
    max_m, min_m = -Float::MAX, Float::MAX
    each do |lr|
      lrmr = lr.m_range
      max_m = lrmr[1] if lrmr[1] > max_m
      min_m = lrmr[0] if lrmr[0] < min_m
    end
    [min_m,max_m]
  else
    [0,0]
  end
end
method_missing(method_name,*args,&b) click to toggle source

Delegate the unknown methods to the rings array

# File lib/geo_ruby/simple_features/polygon.rb, line 16
def method_missing(method_name,*args,&b)
  @rings.send(method_name,*args,&b)
end
text_geometry_type() click to toggle source

WKT geometry type

# File lib/geo_ruby/simple_features/polygon.rb, line 83
def text_geometry_type
  "POLYGON"
end
text_representation(allow_z=true,allow_m=true) click to toggle source

Text representation of a polygon

# File lib/geo_ruby/simple_features/polygon.rb, line 79
def text_representation(allow_z=true,allow_m=true)
  @rings.collect{|line_string| "(" + line_string.text_representation(allow_z,allow_m) + ")" }.join(",")
end