GRASS and Python - Revision history

Neteler: + How to write a Python GRASS GIS 7 addon

2020-12-08T08:20:02Z

+ How to write a Python GRASS GIS 7 addon

← Older revision		Revision as of 08:20, 8 December 2020
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	''Note: For code which needs access to the power of C, you can access the GRASS C library functions via [[GRASS and Python#Python Ctypes Interface\|the Python "ctypes" interface]].''		''Note: For code which needs access to the power of C, you can access the GRASS C library functions via [[GRASS and Python#Python Ctypes Interface\|the Python "ctypes" interface]].''

			=== How to write a Python GRASS GIS 7 addon ===

			The tutorial "How to write a Python GRASS GIS 7 addon" is available here: https://github.com/wenzeslaus/python-grass-addon

	=== Integrated Python shell ===		=== Integrated Python shell ===

Neteler: grass7x URLs -> grass-stable

2020-08-30T20:09:32Z

grass7x URLs -> grass-stable

Show changes

⚠️Eshavers: grammar

2020-06-21T15:30:03Z

grammar

← Older revision		Revision as of 15:30, 21 June 2020
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	''This page discusses usage of GRASS GIS and Python in a general way. If you just want to write a script to run in GRASS GIS go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/grass76/manuals/libpython/ Python API for GRASS GIS 7] documentation.''		''This page discusses usage of GRASS GIS and Python in a general way. If you just want to write a script to run in GRASS GIS, go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/grass76/manuals/libpython/ Python API for GRASS GIS 7] documentation.''

	==Writing Python scripts in GRASS==		==Writing Python scripts in GRASS==

	Python is a programming language which is more powerful than shell scripting but easier and more forgiving than C.		Python is a programming language which is more powerful than shell scripting but easier and more forgiving than C.
	The Python script can contain simple module description definitions which will be processed with {{cmd\|g.parser}}, as shown in the example below. In this way with no extra coding a GUI can be built, inputs checked, and a skeleton help page can be generated automatically. In addition it adds links to the GRASS message translation system. The library for "scripting" is "grass.script", typically used as:		The Python script can contain simple module description definitions which will be processed with {{cmd\|g.parser}}, as shown in the example below. In this way, with no extra coding a GUI can be built, inputs checked, and a skeleton help page can be generated automatically. In addition, it adds links to the GRASS message translation system. The library for "scripting" is "grass.script", typically used as:

	<source lang="python">		<source lang="python">
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	=== Integrated Python editor ===		=== Integrated Python editor ===

	The [[wxGUI]] Layer Manager in GRASS GIS 7.2.0+ comes with a "Simple Python Editor" which enables users to author Python scripts directly in GRASS GIS GUI. ~~User~~ can also run the script easily in GRASS GIS environment with all the dependencies loaded. The editor comes with several examples, templates, and links to documentation.		The [[wxGUI]] Layer Manager in GRASS GIS 7.2.0+ comes with a "Simple Python Editor" which enables users to author Python scripts directly in the GRASS GIS GUI. Users can also run the script easily in the GRASS GIS environment with all the dependencies loaded. The editor comes with several examples, templates, and links to documentation.

	[[File:Simple python editor v buffer.png\|300px\|thumb\|right\|Python interactive shell (console) and a simple Python editor are a powerful option ~~how to interact~~ with GRASS GIS as well as ~~extent~~ its functionality]]		[[File:Simple python editor v buffer.png\|300px\|thumb\|right\|Python interactive shell (console) and a simple Python editor are a powerful option for interacting with GRASS GIS as well as extending its functionality]]

	=== External Python editors (IDE) ===		=== External Python editors (IDE) ===

⚠️Eshavers: grammar

2020-06-21T15:25:28Z

grammar

← Older revision		Revision as of 15:25, 21 June 2020
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	''This page discusses usage GRASS GIS and Python in a general way if you just want to write a script to run in GRASS GIS go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/grass76/manuals/libpython/ Python API for GRASS GIS 7] documentation.''		''This page discusses usage of GRASS GIS and Python in a general way. If you just want to write a script to run in GRASS GIS go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/grass76/manuals/libpython/ Python API for GRASS GIS 7] documentation.''

	==Writing Python scripts in GRASS==		==Writing Python scripts in GRASS==

Neteler: /* References */ +GRASS GIS and the Python geospatial modules (Shapely, PySAL,...)

2019-11-15T16:12:14Z

References: +GRASS GIS and the Python geospatial modules (Shapely, PySAL,...)

← Older revision		Revision as of 16:12, 15 November 2019
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	* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])		* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])

			* GRASS GIS and the Python geospatial modules (Shapely, PySAL,...)
			** See http://osgeo-org.1560.x6.nabble.com/GRASS-and-the-Python-geospatial-modules-Shapely-PySAL-td4985075.html

	{{Python}}		{{Python}}

Neteler: Editor settings for 4-space indentation

2019-08-18T20:01:41Z

Editor settings for 4-space indentation

← Older revision		Revision as of 20:01, 18 August 2019
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	Be sure to use only white spaces and no tabs to indent Python code!		Be sure to use only white spaces and no tabs to indent Python code!

	~~Settings~~		See: https://trac.osgeo.org/grass/wiki/Submitting/Python#Editorsettingsfor4-spaceindentation

			Editor settings for 4-space indentation
	* '''Geany''' editor:		* '''Geany''' editor:
	** Edit > Preferences > Editor > Intentation tab > Type: Spaces		** Edit > Preferences > Editor > Intentation tab > Type: Spaces
			* GNU Emacs:
			** python-mode default
			* spyder ...
			* pycharm ...

	=== Using the GRASS Python Scripting Library ===		=== Using the GRASS Python Scripting Library ===

Neteler: minor cleanup, more needed

2019-01-24T22:57:25Z

minor cleanup, more needed

← Older revision		Revision as of 22:57, 24 January 2019
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	''This page discusses usage GRASS GIS and Python in a general way if you just want to write a script to run in GRASS GIS go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/~~grass70~~/manuals/libpython/ Python API for GRASS GIS 7] documentation.''		''This page discusses usage GRASS GIS and Python in a general way if you just want to write a script to run in GRASS GIS go to [[GRASS Python Scripting Library]] wiki page or [http://grass.osgeo.org/grass76/manuals/libpython/ Python API for GRASS GIS 7] documentation.''

	==Writing Python scripts in GRASS==		==Writing Python scripts in GRASS==
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	=== Integrated Python shell ===		=== Integrated Python shell ===

	The [[wxGUI]] Layer Manager in GRASS GIS ~~6.4.3+~~ comes with a "Python Shell" which enables users to type and execute Python commands directly in wxGUI environment.		The [[wxGUI]] Layer Manager in GRASS GIS comes with a "Python Shell" which enables users to type and execute Python commands directly in wxGUI environment.

	[[Image:wxgui-pyshell.png\|center\|400px\|Embedded interactive Python Shell in wxGUI Layer Manager]]		[[Image:wxgui-pyshell.png\|center\|400px\|Embedded interactive Python Shell in wxGUI Layer Manager]]
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	=== Creating Python scripts that call GRASS functionality from outside ===		=== Creating Python scripts that call GRASS functionality from outside ===

	For calling GRASS functionality from outside, see the [https://grass.osgeo.org/~~grass70~~/manuals/libpython/script.html#module-script.setup documentation] and also [[Working with GRASS without starting it explicitly]].		For calling GRASS functionality from outside, see the [https://grass.osgeo.org/grass76/manuals/libpython/script.html#module-script.setup documentation] and also [[Working with GRASS without starting it explicitly]].

	Note: This is a more advanced use case of using GRASS' functionality from outside via Python. Commonly, a user will run GRASS Python script from inside a GRASS session, i.e. either from the command line or from the Python shell embedded in the wxGUI ([[:File:Wxgui-pyshell.png\|screenshot]]).		Note: This is a more advanced use case of using GRASS' functionality from outside via Python. Commonly, a user will run GRASS Python script from inside a GRASS session, i.e. either from the command line or from the Python shell embedded in the wxGUI ([[:File:Wxgui-pyshell.png\|screenshot]]).
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	my.extension help		my.extension help

	You can also run "make install" from the top level directory of your GRASS install (say /usr/local/src/grass_trunk/). Running "make install" from the top level just copies the whole of the dist.<YOUR_ARCH>/ directory to the installation directory (e.g. /usr/local/~~grass70~~) and the bin.<YOUR_ARCH>/~~grass70~~ bin file to the bin directory (e.g. /usr/local/bin), and fixes any embedded paths in scripts and configuration files.		You can also run "make install" from the top level directory of your GRASS install (say /usr/local/src/grass_trunk/). Running "make install" from the top level just copies the whole of the dist.<YOUR_ARCH>/ directory to the installation directory (e.g. /usr/local/grass76) and the bin.<YOUR_ARCH>/grass76 bin file to the bin directory (e.g. /usr/local/bin), and fixes any embedded paths in scripts and configuration files.

	cd /path/to/grass_src		cd /path/to/grass_src
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	=== Using the parser to get GUI and standardized CLI ===		=== Using the parser to get GUI and standardized CLI ===

	Read the documentation for [https://grass.osgeo.org/~~grass72~~/manuals/libpython/script_intro.html GRASS GIS Python scripting with script package].		Read the documentation for [https://grass.osgeo.org/grass76/manuals/libpython/script_intro.html GRASS GIS Python scripting with script package].

	For more details, see		For more details, see
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	* Latest and greatest: GRASS 7 Python {{src\|scripts}}		* Latest and greatest: GRASS 7 Python {{src\|scripts}}

	* <strike>[[PythonSwigExamples\|More ~~complicated~~ examples]]</strike> <<-- TODO: update to Ctypes		* <strike>[[PythonSwigExamples\|More complex examples]]</strike> <<-- TODO: update to Ctypes

	Sample script for GRASS 6 raster access (use within GRASS, Spearfish session):		Sample script for GRASS 6 raster access (use within GRASS, Spearfish session):
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	import os, sys		import os, sys
	from grass.lib import grass		from grass.lib import grass

	~~if "GISBASE" not in os.environ:~~
	~~print "You must be in GRASS GIS to run this program."~~
	~~sys.exit(1)~~

	if len(sys.argv)==2:		if len(sys.argv)==2:
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	# run within GRASS Spearfish session		# run within GRASS Spearfish session
	~~# run this before starting python to append module search path:~~
	~~# export PYTHONPATH=/usr/src/grass70/swig/python~~
	~~# check with "import sys; sys.path"~~
	~~# or:~~
	~~# sys.path.append("/usr/src/grass70/swig/python")~~
	~~# FIXME: install the grass bindings in $GISBASE/lib/ ?~~

	import os, sys		import os, sys
	from grass.lib import grass		from grass.lib import grass
	from grass.lib import vector as grassvect		from grass.lib import vector as grassvect

	~~if "GISBASE" not in os.environ:~~
	~~print "You must be in GRASS GIS to run this program."~~
	~~sys.exit(1)~~

	if len(sys.argv)==2:		if len(sys.argv)==2:
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	<source lang="python">		<source lang="python">
	~~grass70~~		grass76
	# ... in the GRASS GIS terminal		# ... in the GRASS GIS terminal
	ipython		ipython
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	* http://www.slideshare.net/search/slideshow?q=pygrass		* http://www.slideshare.net/search/slideshow?q=pygrass

	From FOSS4G2006:		From FOSS4G2006 (initial historical steps):
	* [http://www.foss4g2006.org/materialDisplay.py?contribId=136&sessionId=48&materialId=slides&confId=1 A Python sweeps in the GRASS] - A. Frigeri 2006		* [http://www.foss4g2006.org/materialDisplay.py?contribId=136&sessionId=48&materialId=slides&confId=1 A Python sweeps in the GRASS] - A. Frigeri 2006
	* [http://www.foss4g2006.org/materialDisplay.py?contribId=67&sessionId=48&materialId=slides&confId=1 GRASS goes web: PyWPS] - J. Cepicky 2006 (see also [[WPS]])		* [http://www.foss4g2006.org/materialDisplay.py?contribId=67&sessionId=48&materialId=slides&confId=1 GRASS goes web: PyWPS] - J. Cepicky 2006 (see also [[WPS]])
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	* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])		* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])



	{{Python}}		{{Python}}

Neteler: +The correct editor settings for Python indentation

2018-12-27T21:51:29Z

+The correct editor settings for Python indentation

← Older revision		Revision as of 21:51, 27 December 2018
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	Besides the wxGUI Python shell and script editor, also advanced editors like '''Spyder''' (The Scientific PYthon Development EnviRonment) can be used in connection with GRASS GIS. For details, see [[Tools for Python programming]].		Besides the wxGUI Python shell and script editor, also advanced editors like '''Spyder''' (The Scientific PYthon Development EnviRonment) can be used in connection with GRASS GIS. For details, see [[Tools for Python programming]].

			==== The correct editor settings for Python indentation ====

			Be sure to use only white spaces and no tabs to indent Python code!

			Settings
			* '''Geany''' editor:
			** Edit > Preferences > Editor > Intentation tab > Type: Spaces

	=== Using the GRASS Python Scripting Library ===		=== Using the GRASS Python Scripting Library ===

Neteler: fix g.region call

2018-01-17T12:53:10Z

fix g.region call

← Older revision		Revision as of 12:53, 17 January 2018
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	# set computational region		# set computational region
	input = 'elevation'		input = 'elevation'
	g.region(~~rast~~=input)		g.region(raster=input)

	# hardcoded:		# hardcoded:
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	g.message("Filter elevation map by a threshold...")		g.message("Filter elevation map by a threshold...")
	# set computational region		# set computational region
	g.region(~~rast~~=curr_raster)		g.region(raster=curr_raster)

	# generate GeoTIFF		# generate GeoTIFF

⚠️Wenzeslaus: /* Python SIGs */ make the page shorter, if users are interested in Python Special Interest Groups, they will find them themselves

2016-08-05T01:40:29Z

Python SIGs: make the page shorter, if users are interested in Python Special Interest Groups, they will find them themselves

← Older revision		Revision as of 01:40, 5 August 2016
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	* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])		* Zambelli, P., Gebbert, S., Ciolli, M., 2013. ''Pygrass: An Object Oriented Python Application Programming Interface (API) for Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS)''. ISPRS International Journal of Geo-Information 2, 201–219. ([http://dx.doi.org/10.3390/ijgi2010201 DOI] \| [http://www.mdpi.com/2220-9964/2/1/201/pdf PDF])

	~~=== Python SIGs ===~~
	Python Special Interest Groups are focused collaborative efforts to develop, improve, or maintain specific Python resources. Each SIG has a charter, a coordinator, a mailing list, and a directory on the Python website. SIG membership is informal, defined by subscription to the SIG's mailing list. Anyone can join a SIG, and participate in the development discussions via the SIG's mailing list. Below is the list of currently active Python SIGs, with links to their resources.

	~~See more at http://www.python.org/community/sigs/~~

	{{Python}}		{{Python}}