Bug report #20541
"Topology Checker" and multipart (shapefiles)
|Category:||C++ plugins/Topology checker|
|Affected QGIS version:||3.7(master)||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||28361|
In QGIS 3 shapefiles are now always multipart, so the Topology Checker rule "must not have muultipart feature" always return errors for such datasource.
Prerequisite: Polygon shape (see attached shapefile) with clean topology after im- and export with GRASS (v.in.ogr.qgis, snapping threshold 0.1 m):
without invalid/overlapping/multipart geometries, without duplicates, with some allowed gaps.
QGIS 2.18 - Topology Checker (check on invalid/overlapping/multipart/duplicates/gaps) recognizes the gaps. That's correct.
QGIS 3.4.1 - same topology check: The gaps are recognized and a lot of multipart features are reported. But there are no multipart features - so this should be an error.
#2 Updated by Giovanni Manghi over 1 year ago
- Operating System deleted (
- Affected QGIS version changed from 3.4.1 to 3.7(master)
- Status changed from Feedback to Open
- Description updated (diff)
- Subject changed from Plugin "Topology Checker" - false error report: Multipart Features to "Topology Checker" and multipart (shapefiles)
- Category changed from Vectors to C++ plugins/Topology checker
#3 Updated by Dario Bevilacqua over 1 year ago
I have the same problem. I need to check the singlepart and the multipart features and since qgis 3.x it is no more possible.
The command in python 3 (geom.isMultipart()), same as for qgis gui and plugin, return always multipart, even if the geom is single part.
The same file in qgis 2.x and python 2 return the check as "single part".
It's pretty ridiculous that I have to check the geometry with an old and outdated version of qgis. It will be fixed?