I have two polygons in different layers. I am trying to find the intersect between the two polygons. Below a figure showing my test case. I initially wanted to find the intersect between the green polygon and a bunch of other polygons and wrote a code for that. For all but one polygon this functioned as expected, shown below is the one polygon for which my function fails.
My code:
from qgis.core import *
from PyQt4.QtCore import *
layer1=None
layer2=None
for lyr in QgsMapLayerRegistry.instance().mapLayers().values():
if lyr.name() =='Poly':
layer1 = lyr
if lyr.name() =='Buffer':
layer2 = lyr
features1 = layer1.getFeatures()
features2 = layer2.getFeatures()
for feature1 in features1:
for feature2 in features2:
geominter=feature1.geometry().intersection(feature2.geometry())
print(geominter.area())
print(geominter.asPolygon())
layer = QgsVectorLayer('Polygon', 'Intersect' , 'memory')
prov = layer.dataProvider()
layer.startEditing()
feat = QgsFeature()
feat.setGeometry(geominter)
prov.addFeatures([feat])
layer.commitChanges()
layer.updateExtents()
QgsMapLayerRegistry.instance().addMapLayers([layer])
layer.triggerRepaint()
This code worked for all other polygons I needed to find the intersect for except this one. The output layer contains one element (as expected) but nothing is plotted. The print outputs of this code are:
30.2517066088
[]
It accurately computes the area of the polygon I expect to obtain but the .asPolygon() output is empty, which I expect is why nothing is plotted. What could be the reason for this, and how can I obtain the intersect between these two polygons?
I am using QGIS version 2.18.11 on Windows 8.
