I am writing a python processing script in QGIS 3. In it, I have polygon geometry objects stored in a list polygonGeoms and I want to dissolve all of it into one geometry. However, when calling the function QgsGeometry.unaryUnion(polygonGeoms), it returns a null geometry. I've used the unaryUnion function before so I know that it should give me the result I want.

To investigate, I exported the geometries as a temporary shapefile layer. And when I use the Dissolve tool in QGIS 3, it also returns a null feature. The Dissolve tool works on the shapefile when I use QGIS 2.18 though, for some reason.

This is a link to the sample shapefile.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.