[GIS] Inverting selection in PyQGIS

pyqgisselect-by-location

I want to select the features that are not equal. So, I made a selection by location where the geometric predicate is equal and then I thought to invert the selection. Is there any way to invert the selection using PyQGIS?

My code:

import processing
layer1 = processing.getObject('polygon1')
layer2 = processing.getObject('polygon2')

processing.runalg('qgis:selectbylocation', layer2, layer1, u'equals', 0.005,0)

#INVERT SELECTION

Best Answer

Assuming layer2 is the layer holding selection, just use:

layer2.invertSelection()

Related Solutions

[GIS] Using Select Layer by Location in ModelBuilder

"NEW_SELECTION" actually refers to the selection type. Selection types include:

NEW_SELECTION —The resulting selection replaces any existing selection. This is the default.

ADD_TO_SELECTION —The resulting selection is added to an existing selection if one exists. If no selection exists, this is the same as the NEW_SELECTION option.

REMOVE_FROM_SELECTION —The resulting selection is removed from an existing selection. If no selection exists, this option has no effect.

SUBSET_SELECTION —The resulting selection is combined with the existing selection. Only records that are common to both remain selected.

SWITCH_SELECTION —Switches the selection. All records that were selected are removed from the selection; all records that were not selected are added to the selection. The Expression is ignored when this option is specified.

CLEAR_SELECTION —Clears or removes any selection. The Expression is ignored when this option is specified. Source

To get the results of one tool to be used as the input for another, you will need to mark that output as a parameter (right click-->check Model Parameter)

If you need the outputs of your model tool to appear in the Results window, you must make those outputs model parameters. For example, if your tool outputs an HTML file and you want the user to be able to click on that file from the Results window you must make the HTML output file a model parameter.

[GIS] Intersection and add selection in pyqgis

Sorry, guys.. I've tried everything but not the easiest solution:

# get the layers from the interface
grid = iface.activeLayer()
line = iface.activeLayer()

for i in grid.getFeatures():
    for l in line.getFeatures():
        if i.geometry().intersects(l.geometry()):
        # add the selection to the layer
            grid.select(i.id())

Best Answer

Related Solutions

[GIS] Using Select Layer by Location in ModelBuilder

[GIS] Intersection and add selection in pyqgis

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