Bug report #12738
After using "difference" consider 2 or more separated polygons as one
|Affected QGIS version:||2.8.2||Regression?:|
|Operating System:||Easy fix?:|
|Pull Request or Patch supplied:||No||Resolution:||invalid|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||20838|
This bug (unconvinience) appears while working with vector layers, particularly when counting difference (Vector> Geoprocessing> Difference). Sometimes (it depends on sort of data) after subtracting one polygon from another the result looks like 2 or more separated polygons. But as far as minuend was the one polygon, QGIS consider new separated polygons in a new created layer as one polygon, which is not very comfortable to work with. This can be solved by spliting one of the polygons into two objects, after this operation all separated polygons become really independent and separated. And then we can sew splitted part to its parent polygon again, and finally the work is done. But it will be more comfy to have all polygons independent just after running the difference
#3 Updated by Ekaterina Petrunenko over 5 years ago
Alexander Bruy wrote:
Please add sample data to reproduce the bug.
From your description it looks like difference produces multiplolygon features, in this case this is not a bug.
Thank you! I think, you are right, this operation creates multiplolygon features. Could you please advise civilized way to turn multiplolygon feature into independent polygons?