Geometry checker into processing

[Djedouas]

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

https://vimeo.com/991495790

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

[github-actions]

🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit cc42df1)

🪟 Windows Qt6 builds

Download Windows Qt6 builds of this PR for testing.
(Built from commit cc42df1)

[lbartoletti]

Great job @Djedouas and well documented!

[github-actions]

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[lbartoletti]

@Djedouas we go like this, it's tested and used locally. You can carry on, and if we need to improve parts of it, we can always do so.

[pigreco]

@lbartoletti I think it would be great to have an advanced option to define the area of ​​the holes to check

[lbartoletti]

@lbartoletti I think it would be great to have an advanced option to define the area of ​​the holes to check

Please, can you open a dedicated Issue/Feature request? Thanks

[pigreco]

@lbartoletti

Please, can you open a dedicated Issue/Feature request? Thanks

#60079

[qgis-bot]

@Djedouas
This pull request has been tagged as requiring documentation.

A documentation ticket will be opened at https://github.com/qgis/QGIS-Documentation when this PR is merged.

Please update the description (not the comments) with helpful description and screenshot to help the work from documentors.
Also, any commit having [needs-doc] or [Needs Documentation] in will see its message pushed to the issue, so please be as verbose as you can.

Thank you!

[qgis-bot]

@Djedouas
A documentation ticket has been opened at qgis/QGIS-Documentation#9530
It is your responsibility to visit this ticket and add as much detail as possible for the documentation team to correctly document this change.
Thank you!

[agiudiceandrea]

@Djedouas, as well as adding the proper documentation in the docs or providing enough info for those who will do it, I would also suggest to extend and improve the shortHelp string of each processing algorithm being a little bit more descriptive and, e.g., clarify the meaning of the "Tolerance" advanced parameter.

[Djedouas]

@agiudiceandrea thanks for reviewing :)

I will create a PR in the coming weeks to add all the remaining checks and fixes in processings, so all feedback is welcome :)

I will in the same time add (or help) the documentation creation.