QEP 411: On-the-fly contour line labeling for raster layers

[Geojim]

Adds on-the-fly contour line labels for raster DEM layers using GDAL's contour API and the PAL labeling engine.

Reference issue: qgis/QGIS#53415
Reference implementation: qgis/QGIS#65140

[nyalldawson]

@Geojim please disclose ai use when writing this Qep, as per https://github.com/qgis/QGIS-Enhancement-Proposals/blob/master/qep-408-ai-tool-policy.md.

It is not acceptable to rely solely on ai tool use for qgis development.

[Geojim]

Sorry, was just trying to follow the template. Added AI disclosure now.

[nyalldawson]

So @Geojim -- sorry to be blunt here -- but you've never made substantial contributions to C++ qgis before. How can the project have any confidence that your "code review" has any real value? It's harsh, but that's the reality of open source in 2026.

This is a tricky project, which requires in depth knowledge of qgis labelling engine. I don't think it's appropriate for a beginner qgis Dev to implement with a heavy reliance on ai.

Start smaller, contribute in little fixes which build YOUR knowledge of the QGIS code base and architecture. Build your reputation first. And then return to larger contributions like this when you've proved your capabilities.

[Geojim]

@nyalldawson Fair enough. Was just trying to find common ground between a 3-year-old ticket and something actionable. I get the picture - won't bother emailing this out to the list.

[nyalldawson]

Thanks for the understanding @Geojim. Please know I don't like having to put up these barriers -- I wish we could still be the same welcoming community we were before the llm explosion 😭