[PROJ] 2D Helmert transformation after the map projection and PROJ won't use added transformation from the database

[Schupp, Leon]

Hello everyone,

I got 2 Questions.

First question:
Is it possible to add a 2D Helmert transformation to the proj.db database. I tried adding it to the helmert_transformation_table, but proj.db didn't let me choose a projected crs as source transformation.
I want to add a helmert transformation which uses ETRS89/GK25 as source crs and transforms it into the finnish VVJ crs.

My second question is:
I tried adding the helmert transformation as a proj string to the other_transformation table, but proj won't use it. I also added an entry into the usage table for the transformation.
When I add a normal helmert transformation or a grid transformation, proj has no problem using them after they are added, but not when I add a transformation in other_transformation.

Thanks for your help.

Leon Schupp
Student - Development Engineer


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