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

[Klaus Mithöfer]

Hi Andrea

i use proj 9.4.0. I want to add a transformation similar to an existing 
one (code 15984 EPSG 32467 to 258322). But I want to use a different 
Transformation grid.

Proj.db has a table grid_transformation. I have added a data set similar 
to 15984 to code 15984 but with a different grid name. the Grid is 
stored in the proj folder. But the transformation did not show up when 
addig the data - only the existing ones.

Kind regards

Klaus

Am 28.04.26 um 16:54 schrieb Andrea Giudiceandrea via QGIS-User:
> 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
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