[Qgis-user] Integrate custom transformation to Proj Database for use in QGIS

[Andrea Giudiceandrea]

Hi Klaus,
AFAIK the officially supported method to use a custom NTv2 grid shift 
file is described in the QGIS Desktop User Guide / Manual at 
https://docs.qgis.org/3.44/en/docs/user_manual/working_with_projections/working_with_projections.html#integrate-an-ntv2-transformation-in-qgis

Modifying the PROJ database proj.db is not officially supported. The 
structure of such database and the tables that needs to be modified may 
differs from version to version, thus the exact way to modify it depends 
on the PROJ version.

What is the PROJ version used by QGIS in your system?

How do you exactly modified proj.db?

Regards.

Andrea