## NAME

v.out.ogr

## DESCRIPTION

v.out.ogr converts GRASS vector data to OGR format. OGR (Simple Features Library) is part of the GDAL library, so you need to install gdal to use v.out.ogr.

### Supported OGR Vector Formats

ESRI Shapefile
CSV
GML
KML
Mapinfo File
PostgreSQL/PostGIS
TIGER

For further available drivers go here.

## NOTES

To export areas with holes into, e.g., a Shapefile, while keeping the holes as holes, the flag -c has to be used.

The "-z" flag can be used to automatically export a 3D map to a 3D Shapefile, instead of setting the correct lco= option manually.

## EXAMPLES

### Export to Shapefile

Export lines from GRASS vector map to Shapefile format:

    v.out.ogr input=lines type=line dsn=lines.shp

Export areas from GRASS vector map to Shapefile format, preserving islands:

    v.out.ogr -c input=areas_islands type=area dsn=areas_islands.shp

Export 3D lines from GRASS vector map to Shapefile format:

    v.out.ogr input=lines_3d type=line dsn=lines_3d.shp lco="SHPT=ARCZ"

Export 3D points (e.g., Lidar points) from GRASS vector map to Shapefile format

    v.out.ogr points_3d type=point dsn=points_3d.shp lco="SHPT=POINTZ"

Export 3D faces from GRASS vector map to Shapefile format:

    v.out.ogr input=objects_3d type=face dsn=faces_3d.shp lco="SHPT=POLYGONZ"

Export 3D faces from GRASS vector map to Shapefile format, automatic 3D setting:

    v.out.ogr input=objects_3d type=face dsn=faces_3d.shp -z"

### Export to GML

Export lines from GRASS vector map to GML format (generates /tmp/testogr.gml file with layer 'testogr'):

    v.out.ogr input=multi type=line dsn=/tmp/testogr.gml olayer=testogr format=GML

### Export to PostgreSQL/PostGIS

Export areas from GRASS vector map directly to PostGIS:

    v.out.ogr input=polygons type=area \
              dsn="PG:host=localhost dbname=postgis user=postgres" \
              olayer=polymap format=PostgreSQL

### Export to KML (Google Earth)

Example 1 (Latitude-Longitude location):
Export faces (3D vectors) from GRASS vector map to KML format for Google Earth:

    v.out.ogr input=buildings_3d dsn=buildings_3d.kml olayer=buildings_3d \
              format=KML type=face

Example 2 (Latitude-Longitude location):
Generate and export GRASS vector "asteroid" map (faces, 3D vectors) to KML format for Google Earth:

    # near Raleigh (NC, USA)
    g.region n=35.73952587 s=35.73279182 w=-78.68263928 e=-78.67499517

    # two layers of random points
    v.random -z output=random3d_a n=10 zmin=0 zmax=200
    v.random -z output=random3d_b n=15 zmin=400 zmax=600

    # merge into one 3D points map
    v.patch input=random3d_a,random3d_b output=random3d

    # generate 3D convex hull
    v.hull input=random3d output="random3d_hull"

    # export to KML 3D
    v.out.ogr input=random3d_hull dsn=random3d_hull.kml format=KML \
              type=face dsco="AltitudeMode=absolute"

    # now open KML file 'random3d_hull.kml' in Google Earth or NASA WorldWind or ...

## REFERENCES

OGR vector library
OGR vector library C API documentation

## SEE ALSO

db.out.ogr, v.external, v.in.ogr

## AUTHORS

Radim Blazek, ITC-Irst, Trento, Italy
Some contributions: Markus Neteler, Martin Landa

Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $

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