Bug report #14292
'Merge Selected Features' does not remove unnecessary nodes
| Status: | Closed | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: | - | ||
| Category: | Digitising | ||
| Affected QGIS version: | master | Regression?: | No |
| Operating System: | Easy fix?: | No | |
| Pull Request or Patch supplied: | No | Resolution: | wontfix |
| Crashes QGIS or corrupts data: | No | Copied to github as #: | 22283 |
Description
1.) add a new polygon feature
2.) use 'Split Features' tool to split the feature
3.) use 'Merge Selected Features' tool to merge the features
Now there are new nodes where the features were merged. This may cause trouble processing geometries:
http://gis.stackexchange.com/questions/180593/unexpected-behaviour-using-st-equals-with-qgis
History
#1
Updated by Nyall Dawson about 8 years ago
- Resolution set to wontfix
- Status changed from Open to Closed
I don't think this is a bug... It's not safe to auto remove these, as floating point inaccuracies will slightly alter the geometry when the split operation is performed. Use the hausdorff distance instead as a "fuzzy" comparison (http://postgis.net/docs/ST_HausdorffDistance.html), or run a simplify on the resultant geometry with a very small tolerance to try and remove these extra vertices.
#2
Updated by Paul Kanelli about 8 years ago
Thanks for your detailed explanation!