[PROJ] Problems adding geoidmodel tag

[Javier Jimenez Shaw]

How could I know in advance that it is not using the geoid model file from
Slovakia? They (unfortunately) use the same vertical system, and the
accuracy in both cases is 0.03 m
https://epsg.org/transformation_10568/ETRS89-CZE-2007-to-ETRS89-CZE-2007-Baltic-1957-height-2.html
https://epsg.org/transformation_8361/ETRS89-SVK-SKTRF09-to-ETRS89-SVK-SKTRF09-Baltic-1957-height-1.html

Thanks.

On Tue, 3 Mar 2026 at 17:41, Even Rouault <even.rouault at spatialys.com>
wrote:

> Javier,
>
> not much you can do but not setting a manual geoid model for that case.
> The pipeline used is highly manually tuned
> from
> https://github.com/OSGeo/PROJ/blob/master/data/sql/transformations_czechia.sql#L99
> and
>
> https://github.com/OSGeo/PROJ/blob/master/data/sql/transformations_czechia.sql#L171
> for operating on the CRS defined from the exact EPSG codes. Would be
> very hard to make PROJ realize that your custom WKT would be
> compatible of that pipeline
>
> (The pipeline you get with the geoid model node is not fundamentally
> wrong, just slightly less accurate w.r.t. CUZK recommends for most
> geodesic proof ETRS89 to S-JTSK / Krovak)
>
> Even
>
> Le 03/03/2026 à 17:06, Javier Jimenez Shaw via PROJ a écrit :
> > PROJ_NETWORK=ON projinfo EPSG:4258 EPSG:5514+8357 --3d -o proj --bbox
> > 17.8,49,17.81,49.01
>
> --
> http://www.spatialys.com
> My software is free, but my time generally not.
>
>
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