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I'm trying to run the following python script:

from qgis.core import * import sys import os import qgis.utils from qgis.analysis import * app = QgsApplication([],True,"") # supply path to where is your qgis installed QgsApplication.setPrefixPath("/Applications/QGIS.app/Contents/MacOS/", True) # load providers QgsApplication.initQgis() sys.path.append("/Applications/QGIS.app/Contents/Resources/python/plugins") import processing layer3 = QgsVectorLayer("../output/precinctsZipcodes.shp", "intersect", "ogr") if layer3.isValid(): print "Loaded layer 3" else: print "Layer 3 failed to load!" processing.runalg("qgis:exportaddgeometrycolumns", layer3, 0, "../output/precinctsZipcodesArea.shp") QgsApplication.exitQgis()

However, the line processing.runalg("qgis:exportaddgeometrycolumns", layer3, 0, "../output/precinctsZipcodesArea.shp") isn't saving any output. The strange thing is that this syntax works when I run it directly in the python console. Does anybody know what might be happening?

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    Along with what @gcarrillo has mentioned with changing paths and such, try replacing processing.runalg with general.runalg. Commented Nov 6, 2015 at 10:46
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    You're right Joseph, general.runalg() is the way I call QGIS processing algorithms from standalone scripts, as you can also see in my answer. Commented Nov 6, 2015 at 17:17

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Not sure of what could be happening there, but the next code snippet has worked for me on my GNU/Linux machine:

# Prepare the environment import sys from qgis.core import * from PyQt4.QtGui import * app = QApplication([]) QgsApplication.setPrefixPath("/usr", True) QgsApplication.initQgis() # Prepare processing framework sys.path.append('/home/germap/.qgis2/python/plugins') from processing.core.Processing import Processing Processing.initialize() from processing.tools import * # Run the algorithm layerInput = QgsVectorLayer('world_adm0.shp', 'test', 'ogr') general.runalg("qgis:exportaddgeometrycolumns", layerInput, 0, "tmp.shp") # Exit applications QgsApplication.exitQgis() QApplication.exit()

I successfully got the tmp.shp file saved in the folder from which I run the script. Could you give it a try? Just adjust QGIS prefix and other paths to reflect your system configuration.

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