[PROJ] grid shift with GDA2020

[Pierre Chaponniere]

Dear Proj community,

i am looking at transforming data into GDA2020 MGA zone 54 :

+proj=utm +zone=54 +south +ellps=GRS80 +units=m +no_defs +type=crs


But it seems this projection is associated with a transformation grid

https://www.icsm.gov.au/datum/gda-transformation-products-and-tools/transformation-grids


I have therefore dowloaded the corresponding .gsb transformation files

https://github.com/icsm-au/transformation_grids

However when I apply the transformation, it appears the process does not
use the transformation files and generate data with planimetric and
vertical offsets.

How can I make sure the transformation grid are applied and what file makes
the link between proj code and transformation files - is this stored in
proj.db ?

Thanks for your help !
Best regards,

Pierre C
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