GRASS GIS manual: v.external.out

NAME

v.external.out - Defines vector output format.

KEYWORDS

vector, export, output, external, OGR, PostGIS

SYNOPSIS

v.external.out
v.external.out help
v.external.out [-frpg] dsn=string format=string [options=string[,string,...]] [--verbose] [--quiet]

Flags:

-f: List supported formats and exit
-r: Cease using OGR/PostGIS, revert to native output and exit
-p: Print current status
-g: Print current status in shell script style
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

dsn=string [required]: Name of input OGR or PostGIS data source; Examples:
        ESRI Shapefile: directory containing a shapefile
        MapInfo File: directory containing a mapinfo file
        PostGIS database: connection string, eg. 'PG:dbname=db user=grass'
format=string [required]: Format for output vector data; Options: BNA, CSV, DGN, ESRI_Shapefile, GML, GMT, GPX, GeoJSON, Geoconcept, Interlis_1, Interlis_2, KML, MapInfo_File, Memory, MySQL, ODBC, PostgreSQL, S57, SQLite, TIGER; Default: ESRI_Shapefile
options=string[,string,...]: Creation options; Examples:
        'SHPT=POINTZ': create 3D point Shapefile data
        'GEOM_TYPE=geography': use geography PostGIS data
        'SCHEMA=grass': create new PostGIS tables in 'grass' schema

DESCRIPTION

v.external.out instructs GRASS to write vector maps in external data format (e.g. ESRI Shapefile) using OGR library. PostGIS data can be also written by built-in GRASS-PostGIS data driver.

EXAMPLES

ESRI Shapefile

v.external.out can be used along with v.external to process external geodata in GRASS while writing out the results directly eg. in ESRI Shapefile format:

# register Shapefile in GRASS mapset:
v.external dsn=/path/to/shapefiles layer=cities

# define output directory for GRASS calculation results:
v.external.out dsn=$HOME/gisoutput

# do something (here: spatial query), write output directly as Shapefile
v.select ainput=cities atype=point binput=forests btype=area operator=within output=fcities

Current settings can be printed using -p or -g flag.

v.external.out -p

dsn: /path/to/home/gisoutput
format: ESRI Shapefile

PostGIS

PostGIS data can be accessed directly using GRASS-PostGIS data driver (it requires that GRASS is compiled with PostgreSQL support).

# register PostGIS table in GRASS mapset:
v.external dsn=PG:dbname=gisdb layer=cities

# define output directory for GRASS calculation results:
v.external.out dsn=PG:dbname=gisdb format=PostgreSQL

# do some processing...

Note: If the environment variable GRASS_VECTOR_OGR exists, or GRASS is compiled without PostgreSQL support then GRASS will use OGR-PostgreSQL driver for reading and writing PostGIS data.

GRASS native format

To restore original settings, ie. use GRASS native format, type:

v.external.out -r

REFERENCES

OGR vector library C API documentation

AUTHOR

Martin Landa, Czech Technical University in Prague, Czech Republic

Last changed: $Date: 2012-03-28 06:51:46 -0700 (Wed, 28 Mar 2012) $

Main index - Vector index - Full index