I am trying to use GRASS algorithms in a plugin of mine, in order to improve the quality of a shapefile containing lines that will be used as a graph later. The first algorithm I want to use is the one that breaks the lines at their intersections : v.clean.break.

path_to_broken_lines = processing.runalg(
                "grass:v.clean",                                    #Algorithm name
                input,                                              #Path to the layer to break
                0,                                                  #Tool (0<=>break)
                0,                                                  #Threshold (not needed for this algorithm)
                "%f , %f, %f, %f "% (xmin , xmax , ymin , ymax),    #GRASS_REGION_PARAMETER <ParameterExtent>
                -1,                                                 #GRASS_SNAP_TOLERANCE_PARAMETER <ParameterNumber>
                0,                                                  #GRASS_MIN_AREA_PARAMETER <ParameterNumber>
                None,                                               #Errors file (None <=> temporary file)
                None)                                               #Output file path (None <=> temporary file)

Now, despite being the admin of my computer, I get an error saying that my company's policy is blocking the execution of the algorithm. Still, I can execute them manually by running the GRASS plugin, importing my file into grass (v.in.ogr) and using the algorithm afterwards, but it seems like I can't automate it.

My question is the following : is there a way to use "processing.runalg()" as admin ? I have found ways to execute shell scripts as an admin but it is not really the same problem, is it. The plugin would work if I launched QGIS as an administrator, but I do not really want to force the end users to launch QGIS as an admin just to be able to run a plugin they won't use daily.

1 Answer 1


Have you tried processing.runandload() ?

I'm using that when I run a grass:v.voronoi function and that works fine.

  • I've just tried it, unfortunately it doesn't work. It is the same error. I wonder how I can use the algorithm manually, but get blocked when trying to automate it, it makes no sense. :(
    – Ril8772
    Jul 26, 2016 at 7:10

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