Bug report #9673
some polygons not labelled when layer's simplification is on
|Affected QGIS version:||master||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||fixed/implemented|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||18240|
When simplification is activated for a given layer, labels might not be rendered for all of the layer's polygons. I'm attaching a simple shapefile that shows this issue.
Steps to reproduce:
1. Create an empty project and insert the province_2014 shapefile (polygon)
2. Make sure simplification is active for the added polygon layer
3. Open the labelling property window, and set the label to show PROV_NAME string column, and apply the settings
4. You'll notice three polygons (bottom left) are not labelled, for no visible reasons as the labels would not collide (see attached missing_labels.png)
5. Open the layer's property window, deactivate simplification, and apply; the missing labels will appear.
#3 Updated by Mathieu Pellerin - nIRV about 6 years ago
Alvaro, great, will verify when the pull is committed to qgis master.
This should definitively be backported to a 2.2.X release, I've already heard users over in Cambodia complaining about mysterious label going missing. It's a known limitation that historically the QGIS PAL engine didn't put label on invalid geometry. But in this case, the users don't know simplification results in invalid geomtry, making it very hard to diagnose (i.e. running a ftool geometry validity run on layer won't reveal how simplification invalidates it).