Bug report #978
topological editing with snapping to segment yields 2 vertices instead of 1 adding vertex
|Affected QGIS version:||Regression?:||No|
|Operating System:||All||Easy fix?:||No|
|Pull Request or Patch supplied:||Resolution:||fixed|
|Crashes QGIS or corrupts data:||Copied to github as #:||11037|
1. Add a line or polygon Shapefile or PostGIS layer.
2. In project properties enable topological editing, set snapping mode "to segment" or "to vertex and segment".
3. Digitize a line or boundary.
4. Add a vertex on it, move it - you see 2 vertices were added instead of 1. Topology broken.
#3 Updated by Tim Sutton about 12 years ago
- Status changed from In Progress to Closed
- Resolution set to worksforme
Cant replicate. I created a new line using the 'lines' layer in tests/testdata. Digitised a line across one of the roads with a vertex snapped to the road I was crossing. When I subsequently move the vertex, 4 red guides appear and both features are modified in shape as I drag the vertex around.
I'm marking this as 'works for me'. Please advise with more detail if there is something I'm missing and we can adjust the status of the ticket accordingly.
#4 Updated by Maciej Sieczka - about 12 years ago
- Resolution deleted (
- Status changed from Closed to Feedback
You need to set snapping different than 0 for the given layer to notice the bug.
The greater snapping threshold, the greater chance of reproducing the error - at 10 I have 100% "success" of adding 3 vertices instead of 1 in a line Shapefile layer.
Please please fix it before release.
#7 Updated by Maciej Sieczka - about 12 years ago
I can still reproduce the bug in latest trunk 3009c0b9 (SVN r8751). Follow this please:
1. Open the attached shapefile in QGIS.
2. Project properties: check "Enable topological editing".
3. Project properties > Snapping options: check the layer, Mode: "to vertex and segment", Tolerance: "10".
4. Toggle editing.
5. Add a vertex, move it - you'll see 3 vertices were added instead of 1. The attached screendumps show that it really happens.