Bug report #20541
"Topology Checker" and multipart (shapefiles)
| Status: | Open | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: | - | ||
| 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 |
Description
New description:
In QGIS 3 shapefiles are now always multipart, so the Topology Checker rule "must not have muultipart feature" always return errors for such datasource.
Old description:
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.
Observation:
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.
History
#1
Updated by Giovanni Manghi about 6 years ago
- Status changed from Open to Feedback
in QGIS 3 shapefiles are always forced as multipart, so I guess that the tool should consider shapefiles as a special case.
#2
Updated by Giovanni Manghi over 5 years ago
- Operating System deleted (
Windows 7) - 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 5 years 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It's pretty ridiculous that I have to check the geometry with an old and outdated version of qgis.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?
#4
Updated by Giovanni Manghi over 5 years ago
Dario Bevilacqua wrote:
pretty ridiculous
?
have you seen #20541-1 ?
also if there is some bug/regression that is a blocker for your workflow please consider supporting the effort for fixing it, rather than ranting about it.