Geometry checker into processing (Request in QGIS) #9530
Description
Request for documentation
From pull request qgis/QGIS#59637
Author: @Djedouas
QGIS version: 3.42
Geometry checker into processing
PR Description:
Description
Supersedes #55939
This Pull Request aims to integrate the geometry checker in the processing toolbox within the scope of QEP 236.
Each process will follow a consistent logic: one input layer and two distinct outputs.
For check processing outputs are
- a layer of the same type as the input layer with erroneous geometries only
- a point layer with the error locations and information (feature id, part and vertex number, etc.)
For fix processing outputs are
- a fixed layer of the same type as the input layer with corrected features according the the chosen method
- a point layer with the error locations and report about the fix (fixed or not, message about the processed feature)
To ensure a consistent user experience, each process will operate similarly:
A default tolerance parameter is set at 8 (for 1e-8) in the advanced settings of every processing.
Demo video
Screenshots
1. Check errors
Check geometry: errors will be created as a point layer showing places where the angle is < min angle
Launch processing
Errors layer attribute table
Source and errors layer
2. Fix with appropriate processing
Launch the delete vertex processing With the errors layer (output from the previous check) as input
Source and fixed layer (neon red)
Report layer showing what was done
Remarks - feedbacks welcome
The new processes are grouped under new categories named "Check geometry" and "Fix geometry". Suggestions for improved naming are welcome. The aim is to unify verification and correction processes from topology and geometry_checker plugins within these categories.
The current displayName, "Check/FIX Geometry (algorithm name)", is provisional. Any suggestions for enhancing this are welcome.
To avoid overwhelming process options, I've opted to enforce the "gc_" prefix for field names (see outputFields). It's worth considering whether to make this parameter configurable.
Next
Other Geometry Checker processes will be added following this review, and we plan to include additional correction/manipulation processes.
Funded by QGIS (Grant OpenSource 2023) and Oslandia
Part of qgis/QGIS-Enhancement-Proposals#236
cc @lbartoletti