v.out.ogr(1grass) GRASS GIS User's Manual v.out.ogr(1grass)
NAME
v.out.ogr - Exports a vector map layer to any of the supported OGR
vector formats.
By default a vector map layer is exported to OGC GeoPackage format.
KEYWORDS
vector, export, output, OGR, output
SYNOPSIS
v.out.ogr
v.out.ogr --help
v.out.ogr [-uasce2mnl] input=name [layer=string]
[type=string[,string,...]] output=name format=string [out-
put_layer=string] [output_type=string[,string,...]]
[dsco=string[,string,...]] [lco=string[,string,...]] [--overwrite]
[--help] [--verbose] [--quiet] [--ui]
Flags:
-u
Open an existing OGR datasource for update
-a
Append to existing layer
A new OGR layer is created if it does not exist
-s
Skip export of GRASS category ID (’cat’) attribute
-c
Also export features without category (not labeled). Otherwise only
features with category are exported.
-e
Use ESRI-style .prj file format (applies to Shapefile output only)
-2
Force 2D output even if input is 3D (applies to Shapefile output
only)
Useful if input is 3D but all z coordinates are identical
-m
Export vector data as multi-features
-n
Create a new empty layer in defined OGR datasource and exit. Noth-
ing is read from input.
-l
List supported output formats and exit
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
input=name [required]
Name of input vector map to export
Or data source for direct OGR access
layer=string
Layer number or name
Vector features can have category values in different layers. This
number determines which layer to use. When used with direct OGR ac-
cess this is the layer name.
Default: 1
type=string[,string,...]
Feature type(s)
Combination of types is not supported by all output formats. De-
fault is to use first type found in input vector map.
Options: point, line, boundary, centroid, area, face, kernel, auto
Default: auto
output=name [required]
Name of output OGR datasource
For example: ESRI Shapefile: filename or directory for storage
PostGIS database: connection string
format=string [required]
Data format to write
Options: AmigoCloud, BAG, CSV, Carto, Cloudant, CouchDB, DGN, DXF,
ESRI_Shapefile, Elasticsearch, FITS, FlatGeobuf, GML, GMLAS, GPKG,
GPSBabel, GPSTrackMaker, GPX, GeoJSON, GeoJSONSeq, GeoRSS, Geocon-
cept, Interlis_1, Interlis_2, JML, JP2OpenJPEG, KML, LIBKML,
MBTiles, MSSQLSpatial, MVT, MapInfo_File, MapML, Memory, MySQL,
NGW, ODS, OGR_GMT, PCIDSK, PDF, PDS4, PGDUMP, PostgreSQL, S57,
SQLite, Selafin, TIGER, VDV, VICAR, WAsP, XLSX, netCDF
Default: GPKG
output_layer=string
Name for output OGR layer. If not specified, input name is used
For example: ESRI Shapefile: shapefile name
PostGIS database: table name
output_type=string[,string,...]
Optionally change default output type
Options: line, boundary
Default:
line: export area boundaries as linestrings
boundary: export lines as polygons
dsco=string[,string,...]
OGR dataset creation option (format specific, NAME=VALUE)
Default:
lco=string[,string,...]
OGR layer creation option (format specific, NAME=VALUE)
Default:
DESCRIPTION
v.out.ogr converts GRASS vector map layer to any of the supported OGR
vector formats (including OGC GeoPackage, ESRI Shapefile, SpatiaLite or
GML).
OGR (Simple Features Library) is part of the GDAL library, so you need
to install this library to use v.out.ogr.
The OGR library supports many various formats including:
• OGC GeoPackage
• ESRI Shapefile
• PostGIS
• SpatiaLite
• CSV
• GML
• KML
• Mapinfo File
• TIGER
• ... and many others
The list of supported formats is printed with the -l flag.
For further available other supported formats go here.
NOTES
By default, islands will appear as holes inside surrounding areas. To
export polygons with holes into, e.g., a Esri Shapefile, and make the
holes appear as filled areas, the flag -c has to be used.
v.out.ogr exports 3D vector data as 2.5D simple features if possible
(not supported by all formats). For exporting 3D vector data as 2D sim-
ple features, use -2 flag.
By default, v.out.ogr converts GRASS vector data to single simple fea-
tures. If GRASS feature has more categories defined in the given layer,
then this feature is exported multiple times. GRASS features without
category are skipped by default. To export features also without cate-
gory, the -c flag must be given.
When -m flag is given, v.out.ogr export GRASS vector data as multi-fea-
tures. Multi-feature is formed by GRASS features with the same cate-
gory. When -c flag is given, the module also export GRASS features
without category as one multi-feature. Note that multi-features are not
supported by all formats.
ESRI Shapefile export: note that due to the DBF table specifications
column names may not be longer than 10 characters.
Performance: export to SQLite based formats including OGC GeoPackage
may become faster with the environmental variable OGR_SQLITE_CACHE=1024
being set (value depends on available RAM, see OGR ConfigOptions).
EXAMPLES
Export to OGC GeoPackage
Export lines from a GRASS vector map to OGC GeoPackage format:
v.out.ogr input=roadsmajor type=line output=roadsmajor.gpkg
Export areas from GRASS vector map to OGC GeoPackage format, converting
islands (holes) to filled polygons:
v.out.ogr -c input=areas_islands type=area output=areas_islands.gpkg
Export mixed geometry type GRASS vector map to OGC GeoPackage format:
v.out.ogr input=generic_vector output=mixed_geometry.gpkg
Export to ESRI Shapefile
Export lines from GRASS vector map to Shapefile format:
v.out.ogr input=roadsmajor type=line format=ESRI_Shapefile output=lines.shp
Export areas from GRASS vector map to Shapefile format, converting is-
lands (holes) to filled polygons:
v.out.ogr -c input=areas_islands type=area format=ESRI_Shapefile output=areas_islands.shp
Export 3D lines from GRASS vector map to Shapefile format:
v.out.ogr input=lines_3d type=line format=ESRI_Shapefile output=lines_3d.shp lco="SHPT=ARCZ"
Export 3D points (e.g., Lidar points) from GRASS vector map to Shape-
file format
v.out.ogr points_3d type=point format=ESRI_Shapefile output=points_3d.shp lco="SHPT=POINTZ"
Export 3D faces from GRASS vector map to Shapefile format:
v.out.ogr input=objects_3d type=face format=ESRI_Shapefile output=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 format=ESRI_Shapefile output=faces_3d.shp"
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 output=/tmp/testogr.gml output_layer=testogr format=GML
Export to PostgreSQL/PostGIS
Export areas from GRASS vector map to PostGIS database:
v.out.ogr input=polygons type=area output="PG:host=localhost dbname=postgis user=postgres" output_layer=polymap format=PostgreSQL
Note: For exporting GRASS vector data to PostGIS database can be also
used v.out.postgis module. This module is not based on OGR library and
supports beside simple features also topological format (PostGIS Topol-
ogy).
Export to KML (Google Earth)
Export faces (3D vectors) from GRASS vector map to KML format for
Google Earth:
v.out.ogr input=buildings_3d output=buildings_3d.kml output_layer=buildings_3d format=KML type=face
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 output=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
v.out.postgis, db.out.ogr, v.external, v.external.out, v.in.ogr,
v.pack
AUTHORS
Radim Blazek, ITC-Irst, Trento, Italy
Some contributions: Markus Neteler
Multi-feature support by Martin Landa, Czech Technical University in
Prague, 2013
SOURCE CODE
Available at: v.out.ogr source code (history)
Accessed: unknown
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GRASS 7.8.7 v.out.ogr(1grass)
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