PostGIS - Revision history

Neteler: remove version from GRASS (avoid "7")

2025-09-23T07:54:01Z

remove version from GRASS (avoid "7")

← Older revision		Revision as of 07:54, 23 September 2025
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	* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps		* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps

	See also [[Working with external data in GRASS 7\|working with external data in GRASS 7]].		See also [[Working with external data in GRASS\|working with external data in GRASS]].
	__TOC__		__TOC__
	== Help pages ==		== Help pages ==
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	digitize them, but they are not really useful...		digitize them, but they are not really useful...

	''Note 2:'' GRASS 7 allows ~~also~~ reading and writing topological PostGIS data (see [http://www.postgis.org/documentation/manual-2.0/Topology.html PostGIS Topology] for details).		''Note 2:'' GRASS also allows reading and writing topological PostGIS data (see [http://www.postgis.org/documentation/manual-2.0/Topology.html PostGIS Topology] for details).

	{{YouTube\|JoqIkL2VRVc\|desc=Importing PostGIS layers into GRASS}}		{{YouTube\|JoqIkL2VRVc\|desc=Importing PostGIS layers into GRASS}}
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	* input maps: {{cmd\|v.external}}		* input maps: {{cmd\|v.external}}
	**GRASS 7 supports also write access to the map links, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details		**GRASS supports also write access to the map links, see [[Working with external data in GRASS#Vector data\|working with external data in GRASS]] for details
	* output maps: {{cmd\|v.external.out}}		* output maps: {{cmd\|v.external.out}}

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	v.external input=PG:<connection sting> layer=<schema>.<layer> output=<layer>		v.external input=PG:<connection sting> layer=<schema>.<layer> output=<layer>

	''Important note:'' In GRASS 6 the created links area ''read-only''. GRASS 7 also allows to modify linked layers directly via OGR or PostGIS data provider, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details.		''Important note:'' In GRASS 6 the created links area ''read-only''. GRASS also allows to modify linked layers directly via OGR or PostGIS data provider, see [[Working with external data in GRASS#Vector data\|working with external data in GRASS]] for details.

	{{YouTube\|eB3_SmE3E9Q\|desc=Link PostGIS layers as GRASS vector maps}}		{{YouTube\|eB3_SmE3E9Q\|desc=Link PostGIS layers as GRASS vector maps}}
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	v.out.ogr in=lakes@PERMANENT output=PG:dbname=pgis_nc format=PostgreSQL type=area		v.out.ogr in=lakes@PERMANENT output=PG:dbname=pgis_nc format=PostgreSQL type=area

	In GRASS ~~7 exists~~ also specialized module {{cmd\|v.out.postgis}} which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr}}) or in topological format (see [[PostGIS Topology]] for defails).		In GRASS also specialized module {{cmd\|v.out.postgis}} exists which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr}}) or in topological format (see [[PostGIS Topology]] for defails).

	Note that exporting data can be quite time-consuming task, especially when input vector map attributes are stored in DBF format. It's recommended to store attribute data in {{cmd\|grass-sqlite\|desc=SQLite format}} rather then in old-fashioned {{cmd\|grass-dbf\|desc=DBF format}}.		Note that exporting data can be quite time-consuming task, especially when input vector map attributes are stored in DBF format. It's recommended to store attribute data in {{cmd\|grass-sqlite\|desc=SQLite format}} rather then in old-fashioned {{cmd\|grass-dbf\|desc=DBF format}}.
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	See also [[wxGUI Graphical Modeler]].		See also [[wxGUI Graphical Modeler]].

	== Direct access to PostGIS data ~~(GRASS 7 only)~~ ==		== Direct access to PostGIS data ==

	''Important note:'' Direct read/write access is available only in GRASS 7.		''Important note:'' Direct read/write access is available only in GRASS.

	=== Direct read access ===		=== Direct read access ===

	GRASS 7 allows to access PostGIS data directly via virtual mapset called 'OGR'. In this case parameter <tt>map</tt> or <tt>input</tt> is used for OGR data source and <tt>layer</tt> for table. In the command bellow is accessed PostGIS table 'lakes' from database 'pgis_nc'.		GRASS allows to access PostGIS data directly via virtual mapset called 'OGR'. In this case parameter <tt>map</tt> or <tt>input</tt> is used for OGR data source and <tt>layer</tt> for table. In the command bellow is accessed PostGIS table 'lakes' from database 'pgis_nc'.

	v.info map=PG:dbname=pgis_nc@OGR layer=lakes		v.info map=PG:dbname=pgis_nc@OGR layer=lakes
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	=== Direct write access ===		=== Direct write access ===

	GRASS 7 allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out}} module. For example		GRASS allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out}} module. For example

	v.external.out input=PG:dbname=pgis_nc format=PostgreSQL		v.external.out input=PG:dbname=pgis_nc format=PostgreSQL
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	== See also ==		== See also ==

	* [[Working with external data in GRASS 7]]		* [[Working with external data in GRASS]]
	* [[PostGIS Topology]]		* [[PostGIS Topology]]

Pesekon2: little work on style - spaces after `=` were unnecessary and ugly

2025-03-25T19:34:41Z

little work on style - spaces after `=` were unnecessary and ugly

← Older revision		Revision as of 19:34, 25 March 2025
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	# list available PG tables		# list available PG tables
	v.external input="PG:host=myserver user= myuser dbname=pgis_nc" -l		v.external input="PG:host=myserver user=myuser dbname=pgis_nc" -l

	# link PG table into GRASS GIS as vector map		# link PG table into GRASS GIS as vector map
	v.external input="PG:host=myserver user= myuser dbname=pgis_nc" layer=lakes		v.external input="PG:host=myserver user=myuser dbname=pgis_nc" layer=lakes

	The command creates in the current mapset new vector map 'lakes', the module also builds pseudo-topology for this map,		The command creates in the current mapset new vector map 'lakes', the module also builds pseudo-topology for this map,

⚠️Matmar: \output=PG:dbname=pgis_nc\

2017-01-23T03:12:36Z

\*output=PG:dbname=pgis_nc*\

← Older revision		Revision as of 03:12, 23 January 2017
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	To export GRASS vector map layer as PostGIS table use {{cmd\|v.out.ogr}}, eg.		To export GRASS vector map layer as PostGIS table use {{cmd\|v.out.ogr}}, eg.

	v.out.ogr in=lakes@PERMANENT ~~input~~=PG:dbname=pgis_nc format=PostgreSQL type=area		v.out.ogr in=lakes@PERMANENT output=PG:dbname=pgis_nc format=PostgreSQL type=area

	In GRASS 7 exists also specialized module {{cmd\|v.out.postgis}} which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr}}) or in topological format (see [[PostGIS Topology]] for defails).		In GRASS 7 exists also specialized module {{cmd\|v.out.postgis}} which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr}}) or in topological format (see [[PostGIS Topology]] for defails).

Neteler: Updated to G7.2

2017-01-18T13:09:31Z

Updated to G7.2

← Older revision		Revision as of 13:09, 18 January 2017
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	== Link to GRASS ==		== Link to GRASS ==

	* input maps: {{cmd\|v.external~~\|version=70~~}}		* input maps: {{cmd\|v.external}}
	**in GRASS 6 the map links created by {{cmd\|v.external}} are ''read only''
	**GRASS 7 supports also write access to the map links, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details		**GRASS 7 supports also write access to the map links, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details
	* output maps: {{cmd\|v.external.out~~\|version=70~~}} ~~(GRASS 7 only)~~		* output maps: {{cmd\|v.external.out}}

	You can register a PostGIS table in GRASS using {{cmd\|v.external}}. The command ~~bellow~~ creates a link to the table 'lakes' located in database 'pgis_nc'.		You can register a PostGIS table in GRASS using {{cmd\|v.external}}. The command below creates a link to the table 'lakes' located in database 'pgis_nc'.

	v.external ~~dsn~~=PG:dbname=pgis_nc layer=lakes		# list available PG tables
			v.external input="PG:host=myserver user= myuser dbname=pgis_nc" -l

			# link PG table into GRASS GIS as vector map
			v.external input="PG:host=myserver user= myuser dbname=pgis_nc" layer=lakes

	The command creates in the current mapset new vector map 'lakes', the module also builds pseudo-topology for this map,		The command creates in the current mapset new vector map 'lakes', the module also builds pseudo-topology for this map,
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	To link a PostGIS table from non-public schema		To link a PostGIS table from non-public schema

	v.external ~~dsn~~=PG:<connection sting> layer=<schema>.<layer> output=<layer>		v.external input=PG:<connection sting> layer=<schema>.<layer> output=<layer>

	''Important note:'' In GRASS 6 the created links area ''read-only''. GRASS 7 also allows to modify linked layers directly via OGR or PostGIS data provider, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details.		''Important note:'' In GRASS 6 the created links area ''read-only''. GRASS 7 also allows to modify linked layers directly via OGR or PostGIS data provider, see [[Working with external data in GRASS 7#Vector data\|working with external data in GRASS 7]] for details.
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	To export GRASS vector map layer as PostGIS table use {{cmd\|v.out.ogr}}, eg.		To export GRASS vector map layer as PostGIS table use {{cmd\|v.out.ogr}}, eg.

	v.out.ogr in=lakes@PERMANENT ~~dsn~~=PG:dbname=pgis_nc format=PostgreSQL type=area		v.out.ogr in=lakes@PERMANENT input=PG:dbname=pgis_nc format=PostgreSQL type=area

	In GRASS 7 exists also specialized module {{cmd\|v.out.postgis~~\|version=70~~}} which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr~~\|version=70~~}}) or in topological format (see [[PostGIS Topology]] for defails).		In GRASS 7 exists also specialized module {{cmd\|v.out.postgis}} which allows to export GRASS vector data as simple features (similarly to {{cmd\|v.out.ogr}}) or in topological format (see [[PostGIS Topology]] for defails).

	Note that exporting data can be quite time-consuming task, especially when input vector map attributes are stored in DBF format. It's recommended to store attribute data in {{cmd\|grass-sqlite\|desc=SQLite format}} rather then in old-fashioned {{cmd\|grass-dbf\|desc=DBF format}}.		Note that exporting data can be quite time-consuming task, especially when input vector map attributes are stored in DBF format. It's recommended to store attribute data in {{cmd\|grass-sqlite\|desc=SQLite format}} rather then in old-fashioned {{cmd\|grass-dbf\|desc=DBF format}}.
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	</pre>		</pre>

	When accessing external data directly you don't need to create a map link by {{cmd\|v.external~~\|version=70~~}}. The major drawback of direct read access is that the pseudo-topology is built each time when accessing the data. From this point of view the direct access is useful when accessing data once or few times, otherwise is better to link the data by {{cmd\|v.external~~\|version=70~~}}.		When accessing external data directly you don't need to create a map link by {{cmd\|v.external}}. The major drawback of direct read access is that the pseudo-topology is built each time when accessing the data. From this point of view the direct access is useful when accessing data once or few times, otherwise is better to link the data by {{cmd\|v.external}}.

	=== Direct write access ===		=== Direct write access ===

	GRASS 7 allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out~~\|version=70~~}} module. For example		GRASS 7 allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out}} module. For example

	v.external.out ~~dsn~~=PG:dbname=pgis_nc format=PostgreSQL		v.external.out input=PG:dbname=pgis_nc format=PostgreSQL

	causes that output vector data are written in PostGIS format in the database 'pgis_nc'. GRASS also creates automatically for every PostGIS table a new vector map in the current mapset as the link to the PostGIS table.		causes that output vector data are written in PostGIS format in the database 'pgis_nc'. GRASS also creates automatically for every PostGIS table a new vector map in the current mapset as the link to the PostGIS table.

Neteler: +https://strk.kbt.io/projects/rttopo/ RT Topology Library

2016-05-04T07:14:35Z

+https://strk.kbt.io/projects/rttopo/ RT Topology Library

← Older revision		Revision as of 07:14, 4 May 2016
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	* [http://www.postgis.org PostGIS]		* [http://www.postgis.org PostGIS]
	* [http://gdal.org/ogr OGR library]		* [http://gdal.org/ogr OGR library]
	* [http://www.dimensionaledge.com/main/postgis/viewshed-analysis-in-postgis-using-plr-and-grass/ Viewshed analysis in PostGIS using PL/R and GRASS (blog post by Mark Wynter)]		* [http://www.dimensionaledge.com/main/postgis/viewshed-analysis-in-postgis-using-plr-and-grass/ Viewshed analysis in PostGIS using PL/R and GRASS] (blog post by Mark Wynter)
			* [https://strk.kbt.io/projects/rttopo/ RT Topology Library]

	[[Category: FAQ]]		[[Category: FAQ]]
	[[Category: Vector]]		[[Category: Vector]]

⚠️Landa at 14:05, 15 November 2013

2013-11-15T14:05:31Z

← Older revision		Revision as of 14:05, 15 November 2013
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	=== Direct write access ===		=== Direct write access ===

	~~'''Warning:''' direct write access via OGR library is currently '''under development''' (GRASS 7 only).~~

	GRASS 7 allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out\|version=70}} module. For example		GRASS 7 allows to write output vector map directly via OGR library. For defining output vector data format is designed {{cmd\|v.external.out\|version=70}} module. For example

⚠️Landa at 13:59, 15 November 2013

2013-11-15T13:59:07Z

← Older revision		Revision as of 13:59, 15 November 2013
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	When accessing [http://www.postgis.~~org~~ PostGIS] data in GRASS you can		When accessing [http://www.postgis.net PostGIS] data in GRASS you can
	* [[#Import into GRASS\|import]] PostGIS (simple features) data into GRASS topological format or,		* [[#Import into GRASS\|import]] PostGIS (simple features) data into GRASS topological format or,
	* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps		* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps

⚠️Wenzeslaus: /* External links */

2013-02-18T18:20:12Z

External links

← Older revision		Revision as of 18:20, 18 February 2013
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	* [http://www.postgis.org PostGIS]		* [http://www.postgis.org PostGIS]
	* [http://gdal.org/ogr OGR library]		* [http://gdal.org/ogr OGR library]
			* [http://www.dimensionaledge.com/main/postgis/viewshed-analysis-in-postgis-using-plr-and-grass/ Viewshed analysis in PostGIS using PL/R and GRASS (blog post by Mark Wynter)]

	[[Category: FAQ]]		[[Category: FAQ]]
	[[Category: Vector]]		[[Category: Vector]]

⚠️Landa at 13:06, 29 November 2012

2012-11-29T13:06:50Z

← Older revision		Revision as of 13:06, 29 November 2012
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	When accessing PostGIS data in GRASS you can		When accessing [http://www.postgis.org PostGIS] data in GRASS you can
	* [[#Import into GRASS\|import]] PostGIS (simple features) data into GRASS topological format or,		* [[#Import into GRASS\|import]] PostGIS (simple features) data into GRASS topological format or,
	* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps		* [[#Link to GRASS\|link]] PostGIS data as GRASS vector maps

⚠️Landa: /* See also */

2012-11-27T15:20:07Z

← Older revision		Revision as of 15:20, 27 November 2012
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	== See also ==		== See also ==

			* [[Working with external data in GRASS 7]]
			* [[PostGIS Topology]]

			== External links ==

	* [http://www.surfaces.co.il/?p=645 Tutorial by Micha Silver]		* [http://www.surfaces.co.il/?p=645 Tutorial by Micha Silver]