QGis python bindings with arcpy

QGis python bindings with arcpy

OSGeo4WI have very mature development environment in python 2.7.5, centered around ArcPy (ArcGIS python bindings) and iPython (a very useful python shell). I just updated my QGis install (using OSGeo4W64), and I thought I would try to add the QGis python bindings to my existing install - here is how to do it!

ArcGIS (10.2) comes with a Python 2.7.5 install. I have also installed the 64-bit python geoprocessing for ArcGIS, and I have that fully setup. For interactive testing, geoprocessing and running scripts I have found iPython very useful. This is a very useful console/shell for python, with tab completion and various useful tricks. I run this in a tab in the ConEmu console emulator. This is all on Windows 7 64-bit, by the way.

For QGis, I have used the very handy OSGeo4W distribution (64-bit flavor), which wraps a number of free and open source GIS and geography related applications.

Now, OSGeo4W comes with a python distribution that is ready and configured for QGis (and other assorted tools). But I find that two python (ArcGIS 32-bit and 64-bit) installs are enough to keep track of, and I am not keen on adding iPython again to the OSGeo4W mix.

To add the qgis python bindings to the existing python installs were not overly straight-forwards, and I bumped into a lot of errors on the way.

Here are the steps that worked for me:

  1. Make sure that OSGeo4W and python is installed properly
  2. In the OSGeo4W python, find out what version of PyQt4 is installed using these steps:
    • Start the OSGeo4W Shell
    • type python
    • after the interpreter/shell has loaded, type:
      from PyQT4 import QtCore
    • For me, this printed '4.10.2'
  3. Now you need to download and install the matching PyQt4 library. For my 64-bit python 2.7.5  with QGis 2.2.0 this meant this file.
  4. Now you need to set your environment to point at the correct folders. If you have installed OSGeo4W elsewhere, adjust the values accordingly:
    • Add C:\OSGeo4W64\apps\qgis\python to your PYTHONPATH environment variable. You can separate multiple paths by ;.
    • When executing python, add the following paths to your PATH environment variable. I added this to a batch-file that executes iPython, since I prefer to not pollute my system-wide path too much:
      set path=C:\OSGeo4W64\apps\qgis\bin;
  5. When you run python now (or iPython) try:
    import PyQt4.QtGui
    import PyQt4.QtCore
    from qgis.gui import *
    from qgis.core import *

For me, that imports without errors now!