GRASS GIS development

GRASS - Geographic Resources Analysis Support System has been under continual development since 1982. The strength and success of GRASS GIS relies on the user community. With this in mind, the philosophy of the GRASS Development Team is to encourage users to develop their own unique tools and applications for GRASS. If you develop tools and techniques that you feel would benefit other GRASS users, please see below how to structure code and documentation for the benefit of all.

Submitting rules

Be sure to check your code against these rules:

• General notes
• C code
• Python code
• wxGUI code (wxPython-based GUI code)
• Documentation-related notes (HTML, MAN)
• User message standardization: formatting, standard phrases, i18N etc.

GRASS GIS programming best practice

There are many unwritten rules how GRASS modules should work, what they should do and what they shouldn't do. There is always some reason why some things are considered as "good" or "bad", still they are just noted in some long GRASS developer mailing list conversations. These pages here aim at collecting such ideas which are floating around in the ​GRASS-dev mailing list (and other places) to help new module developers/bugfixers to understand many little tricks how GRASS modules should work.

New list item adding guide

List items should be short and general. Add only things that are relevant to all modules or module groups. There should be reason why such rule/hint exists - add reference to ML archive thread or short description why such rule is important. Look into the documentation above for already existing specific rules. Feel free to add code/pseudocode samples, if they apply.

GRASS best practice list (unsorted)

• Read the rules above
• All GRASS modules should accept map names in format "map@mapset". ​http://lists.osgeo.org/pipermail/grass-dev/2008-February/035629.html
• Module should not write/change maps in other mapsets than current mapset. ​http://lists.osgeo.org/pipermail/grass-dev/2008-February/035637.html

GRASS GIS Addons

• Check your code against the Submitting rules (see above)
• Upload your code with the git client (git usage)
• Once uploaded to the GRASS GIS Addons GitHub repository:
  • Addons appear in the ​Addons manual pages when being registered in the parent Makefile
  • note to devs only: the addons are created via cronjobs on the server (user can install them via g.extension)

• GRASS GIS Python Addons
  • with dependencies on external, non-standard modules should use lazy imports: ​https://lists.osgeo.org/pipermail/grass-dev/2018-October/090321.html
  • that represent sets of modules and eventually also share functions across modules can be grouped into one addon directory, like e.g.:
    • ​https://github.com/OSGeo/grass-addons/tree/master/grass7/gui/wxpython/wx.metadata or
    • ​https://github.com/OSGeo/grass-addons/tree/master/grass7/raster/r.green

Submitting code to GitHub

See HowToGit

See also

• ​http://grass.osgeo.org/development/