QGIS clip tool error non-point (MULTIPOINT) geometry to point shapefile

Question

I'm using QGIS 3.22.4 then tried 3.22.7. I am using the clip tool. The input layer is a point(point) shapefile (verified in layer properties under information-geometry section). I have tried this with multiple different polygon overlay layers and all are giving me issues when running the tool if I try to save the result as a shapefile. Error message is "Attempt to write non-point (MULTIPOINT) geometry to point shapefile". On any of these I will get resulting points from the clip but only if I let it run as a temporary layer. Then I need to go and export the temporary layer to a shapefile however i have the same issue there with the same error message UNLESS I check the box for force-multi.

I've tried this with multiple file types including from a KMZ type Polygon(PolygonZ). I then exported the polygon that was originally a kmz into a shape file and regardless of the options I chose on export the resulting shapefile was still Polygon(MultiPolygon) and would produce the same errors. Then I tried running the multipart to singleparts tool on it and the resulting saved shapefile has a geometry type of Polygon(MultiPolygon) still. same result if I try to run the clip tool using that, I have to let it run as a temporary file, then export as a shapefile and choose force multi.

Am I missing something very obvious here?

Is the issue not with the polygon files?

I used to use the clip tool without any issues and now I cannot run anything.

Answer 1

I had the same issue. Could't do a simple clip. I belive issue was fixed in the QGIS version 3.28 (Firenze).

See the changelog and bugfixes: (Title: Fix some overlay algorithms output multipoint geometries but output layer is single point, causing insertion errors)

Answer 2

I believe i got this error recently also, only noticed it since upgrading to 3.22 and i havent done anything different to what i normally would. Maybe just an annoying bug.

I ran a Multipart to Singleparts on the point layer and then i was able to save it, its an annoying extra step, but it works.

Answer 3

I am having this issue. Although, I think I have it worse because I can't even save to a temporary layer. I have tried the conversion but the process only succeeds after selecting two topology types/vector layers that match. I just checked our older QGIS 2.18 installations and everything went along without a hitch.

Answer 4

The bug is known but the issue is still open today(okt.2022): https://github.com/qgis/QGIS/issues/49456