[petrasovaa]

Bug

Importing data with a compound CRS (e.g., NAD83(2011) / North Carolina (ftUS) + NAVD88 height (ftUS), failed with "Coordinate reference system of dataset does not appear to match current project" even when the project was created from that very file. r.import had no way around it: its temporary project is created from the file too, so the import into it failed the same way.

Project creation stores only the horizontal SRID (EPSG:6543) while the CRS check compared the file's full compound CRS against it with OSRIsSameEx(), which never matches. Geographic 3D data (EPSG:4979) had the same problem in the other direction: a project created from such a file gets PROJ_SRID = EPSG:4979 and then rejects ordinary 2D lat-lon data.

Fix

GRASS has no vertical CRS, so check_projection() now compares the horizontal components only, using OSRDemoteTo2D() on clones of both CRSs (GDAL >= 3.1; GRASS requires 3.7). The import itself is unchanged: it never transforms with the file CRS, and r.proj/v.proj already get a horizontal pipeline from PROJ.

Since this drops information the file carries, the tools now say so:

• Vertical CRS <NAVD88 height (ftUS)> of the dataset is ignored
• The vertical component of the dataset CRS is ignored (geographic 3D)

The same change is applied to the four copies of the check code in r.in.gdal, r.external, v.in.ogr and v.external. The lidar/PDAL importers compare via G_compare_projections(), which is already horizontal only.

Tests

New pytest files for the raster tools (r.in.gdal, r.external) and the vector tools (v.in.ogr, v.external), with data generated as small GDAL/OGR VRT files, covering compound and geographic 3D CRSs in both project and file, the message, and that a different horizontal CRS is still rejected. Against the unfixed build 20 of the 28 tests fail.

--

Implemented with the help of Claude Code.

[cwhite911]

What about adding support for vertical CRS on projects? Make it optional but enforce it if it is set.

[petrasovaa]

What about adding support for vertical CRS on projects? Make it optional but enforce it if it is set.

This is a bug fix, adding that feature would be different PR, likely more complicated.

[metzm]

Thanks for this fix!
As I understand, a vertical CRS is specific to a dataset, and it is perfectly valid to have different datasets with the same horizontal, but different vertical CRSs. GDAL can on reprojection apply vertical CRS info to e.g. elevation values, I've been testing this before.
Users should reproject to a 2D CRS with GDAL to be on the safe side before importing into GRASS.

[metzm]

Fixes #7336