QGIS v.clean – Resolving Crashes When Using v.clean in QGIS

Question

I am working on a shapefile depicting English administrative divisions in QGIS 3.16.15. I began first by using the 'Fix geometries' tool to remove invalid geometries. Then, I used the topology editor to identity several thousand gaps and overlaps between the polygons. I am trying to fix these geometries using v.clean, but no matter what option I select, I continuously get the same string of errors in the log.

Then, the program crashes.

Answer 1

I dont know why your attempt does not work. But you should be able to fix it with a more manual approach:

Fix the holes:

1. Dissolve
2. Delete holes
3. Difference with your start layer as input layer, and dissolved layer as overlay. Now you have the holes as small polygons
4. Merge these with the input layer
5. Select them by area and Eliminate

Self intersections:

1. Union the output from above with itself (can take some time)
2. Select the overlaps with "TerrID"<>"TerrID_2"
3. Eliminate them

Then delete the extra fields created in the Union with Refactor fields (or do it manually)