[GIS] Setting up Python 2.7 to work in both QGIS and ArcGIS Desktop

arcgis-10.1arcpyinstallationpyqgispython-2.7

I have both ArcGIS 10.1 and QGIS 1.8 installed and both include Python 2.7 in slightly different setups and in different folders (c:\Python27\ArcGIS10.1\ and c:\Program Files (x86)\Quantum GIS Lisboa\apps\Python27).

It is only ArcGIS Desktop which include python.exe, while it is really QGIS I would like to start experimenting with for some scripting, but preferably just running my scripts from the command console.

How do I do this?

I'm thinking of settings environment variables etc.

I am new to both QGIS and Python.

Best Answer

While you can do it with the standalone installed copy of QGIS I would highly recommend installing QGIS and QGIS-dev using the OSGeo4W installer. OSGeo is easier to update and lets you get the latest stuff.

That will install Python into C:\OSGeo4W\app\Python27 and let you run Python from the OSGeo4W shell. python.exe lives in C:\OSGeo4W\bin.

I have some examples of QGIS stuff at https://github.com/NathanW2/pyqgis-playground

Use the following batch file as a bootstrap to your python file:

@ECHO OFF
set OSGEO4W_ROOT=C:\OSGeo4W
set PATH=%OSGEO4W_ROOT%\bin;%OSGEO4W_ROOT%\apps\qgis-dev\bin;%PATH%
SET PYTHONHOME=%OSGEO4W_ROOT%\apps\Python27
set PYTHONPATH=%OSGEO4W_ROOT%\apps\qgis-dev\python
set QGIS_PREFIX_PATH=%OSGEO4W_ROOT%\apps\qgis-dev\

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If you have used osgeo4w to install QGIS this will be unnecessary, but you could do it anyway as a belt-and-braces approach - it won't hurt). I suspect you will also need to add the lines at the start of the set_qgis_01.py file (I did mine in the GDALTOOLS.py file because that's where my conflict manifested itself).

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