Bug report #21282
[Expression] point_n function should be coherent with other vertex based functions and algorithms
| Status: | Open | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: | - | ||
| Category: | Expressions | ||
| 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 #: | 29100 |
Description
I don't know if I should report it as a bug or a feature request...
The point_n function returns a specific node on a geometry, based on the provided index. The first vertex index is 1.
But when using Processing to extract vertices from a feature, the vertex_index is 0-based. Some other expression that manipulates vertices (angle_at_vertex, distance_to_vertex) are also 0-based.
It could be nice to align the point_n function with the others.
Related issues
History
#1
Updated by Harrissou Santanna about 5 years ago
- Related to Feature request #21284: [Expression] Allow negative value for vertex index in angle_at_vertex/distance_at_vertex/point_n... functions added
#2
Updated by Mathieu Pellerin - nIRV about 5 years ago
- Regression? set to No
- Crashes QGIS or corrupts data set to No
- Affected QGIS version set to 3.7(master)
- Tracker changed from Feature request to Bug report
IMHO, it's an inconsistency which should be considered as a bug. Fixing this will have to wait until we cross the QGIS 4.0 bridge.