[Qgis-user] How do you see which transform is being used for a given projection?

[Andrea Giudiceandrea]

> John Stevenson - BGS jostev at bgs.ac.uk
> Thu Aug 7 05:02:32 PDT 2025

> When I add a layer with OSGB36 (epsg:27700) projection to a project in QGS84 (epsg:4326), I am given an option to select the coordinate transformation to use.  There are multiple options: https://epsg.io/27700.  The best includes a custom correction grid, OSTN15_NTv2.
> 
> Once the layer has been added, is there a way to see which transformation was used?

Hi John,
you should find chosen datum transformation in "Settings -> Options -> 
CRS and Transforms -> Coordinate Transforms" and /or "Project -> 
Properties -> Transformations".

Please see:

- 
https://docs.qgis.org/latest/en/docs/user_manual/introduction/qgis_configuration.html#transformations-properties

- 
https://docs.qgis.org/latest/en/docs/user_manual/introduction/qgis_configuration.html#transformations-options

- 
https://docs.qgis.org/latest/en/docs/user_manual/working_with_projections/working_with_projections.html#datum-transformations


Regards.

Andrea