[PROJ] Correct syntax of vertical datum

[Martin Dobias]

Hi

I am trying to consume data from Slovak national lidar survey, where
the CRS should be defined as a compound CRS using EPSG:3046 (ETRS89 /
UTM zone 34N) as the horizontal CRS and EPSG:4937 (ETRS89) as the
vertical CRS.

The WKT is defined like this in metadata:

COMPD_CS["ETRS89/ETRS-TM34+ETRS89",PROJCS["ETRS89/ETRS-TM34",GEOGCS["ETRS89",DATUM["European_Terrestrial_Reference_System_1989",SPHEROID["GRS1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6258"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4258"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",21],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],AUTHORITY["EPSG","3046"],AXIS["Easting",EAST],AXIS["Northing",NORTH]],VERT_CS[GEOGCS["ETRS89",DATUM["EuropeanTerrestrialReferenceSystem1989",SPHEROID["GRS1980",6378137.0,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0.0,0.0,0.0,0.0,0.0,0.0,0.0],AUTHORITY["EPSG","6258"]],PRIMEM["Greenwich",0.0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.017453292519943295],AXIS["Geodeticlatitude",NORTH],AXIS["Geodeticlongitude",EAST],AXIS["Ellipsoidalheight",UP],AUTHORITY["EPSG","4937"]]]]

When using projinfo, it complains it can't read that WKT with the
following error:
Missing VDATUM or ENSEMBLE node

As far as I understand, according to the WKT specs, the VERT_CS node
should contain a VDATUM node, instead it contains GEOGCS.

Is this WKT invalid or just using some obscure feature that PROJ does
not implement? And if the WKT is wrong, how can I produce a VERT_CS
clause for EPSG:4937 that would be valid, so that I can notify the
authority to fix the metadata?

Regards
Martin