[PROJ] Vertical grid transformation / ellipsoidal height to EGM2008 (EPSG 3855)

[inti luna]

Thank you Noel, Javier and Even,
Thank you very much for your informative response.
Sorry for the Ubuntu mistake, my version is 20.04.

I got coordinates in WGS84 + ellipsoid height since my data was a result of
a PPK process (using as base, one of the correction network) using Emlid
studio and currently, coordinates come like this but thank you for the
clarification regarding the available CRS in Spain and the Alicante height
I was not aware of.

I tested all your proposed solutions and all worked fine on my computer. I
learned a lot, thank you!!

Inti

El jue, 15 sept 2022 a las 22:52, Even Rouault (<even.rouault at spatialys.com>)
escribió:

> Modern solution:
>
> $ echo 43.37551925 -2.69713764 102.635| cs2cs -d 3 EPSG:4979
> EPSG:25830+3855
> 524534.955    4802561.478 53.074
> Not that when using the EPSG:xxx syntax (and not the legacy
> +init=epsg:xxxx one), you need to specify input coordinates in the order
> they are expected by the official definition of the CRS, here latitude,
> longitude, as for all geographic CRS under the EPSG authority (you can
> check the axis order by looking at the WKT output with "projinfo
> EPSG:4979")
>
> You could also get that result with the legacy syntax with:
>
> $ echo -2.69713764 43.37551925 102.635| cs2cs -d 3 +init=epsg:4979 +to
> +init=epsg:25830 +geoidgrids=egm08_25.gtx
> 524534.955    4802561.478 53.074
>
> or using the epsg:4326 code but forcing it to 3d:
>
> $ echo -2.69713764 43.37551925 102.635| cs2cs -d 3 --3d +init=epsg:4326
> +to +init=epsg:25830 +geoidgrids=egm08_25.gtx
> 524534.955    4802561.478 53.074
>
> Even
> Le 15/09/2022 à 22:18, inti luna a écrit :
>
> Dear PROJ community,
> I am using a GNSS (Emlid REACH RS2 )to collect ground control points for
> drone mapping and supporting a project of monitoring vegetation after fire.
> I have collected data in LAT,LON (CRS EPSG 4326) and ellipsoidal height (m)
> and would like to transform it to another CRS. Target horizontal is EPSG:
> 25831 and target height is based on EGM2008 (EPSG 3855).
>
> I just discovered PROJ and I am having issues with the vertical
> transformation.
>
> Using Linux Ubuntu 11 and installed PROJ using anaconda with:
>
> <conda install -c conda-forge proj>
>
> <conda install -c conda-forge proj-data>
>
> I tested with:
>
> <echo -2.69713764 43.37551925 | cs2cs +init=epsg:4326 +to +init=epsg:25830>
>
> which outputs: -2.69713764 43.37551925 which is fine.
>
> However, I don't understand very well how to perform the vertical grid
> shift.
>
> I tried:
>
> 1. <echo -2.69713764 43.37551925 102.635| cs2cs +init=epsg:4326
> +vgridshift  +to +init=epsg:25830 +grids=egm08_25.gtx>
>
> 2.<echo -2.69713764 43.37551925 102.635 | proj +init=epsg:4326
> +proj=vgridshift +grids=egm08_25.gtx>
>
> But the first try ignores the height and the second got me an error
> message:
>
> "can't initialize operations that produce angular output coordinates
> program abnormally terminated"
>
> Thank you for your help,
>
> Inti
>
>
>
>
> --
> Inti Luna
> + 34 688756449
>
>
>
> _______________________________________________
> PROJ mailing listPROJ at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/proj
>
> -- http://www.spatialys.com
> My software is free, but my time generally not.
>
>

-- 
Inti Luna
+ 34 688756449
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20220916/c8fa18bd/attachment-0001.htm>