[PROJ] PROJ and nadgrids vs hgridshift +grids

[David Fileccia]

I need to get the grid shift of the NtV2 files for the Australian National Grid 1984. I can use the .TIF files in the PROJ data but I also need to be able to use the original GSB file for customers that only understand the official government data.

My current setup for the .TIF file is:
      const std::string p = "+proj=pipeline "
            "+step +proj=unitconvert +xy_in=deg +xy_out=rad "
            "+step +proj=hgridshift +grids=<gridpath>.tif +inv "
            "+step +proj=unitconvert +xy_in=rad +xy_out=deg ";

I tried:
      const std::string p = "+proj=pipeline "
            "+step +proj=unitconvert +xy_in=deg +xy_out=rad "
            "+step +nadgrids=<gridpath>.gsb +inv "
            "+step +proj=unitconvert +xy_in=rad +xy_out=deg ";

Of course, this failed saying it is an invalid pipeline.

What is the correct pipeline for this procedure?

Best Regards,

David Fileccia
Senior Systems Engineer | HEMISPHERE GNSS
Office: 6860 Little Twin Road, Germantown, OH 45327, USA
Corporate: 8515 E. Anderson Drive, Scottsdale, AZ 85255, USA
M: +1 404 579 4391
dfileccia at hgnss.com<mailto:dfileccia at hgnss.com> | www.hgnss.com<http://www.hgnss.com/>
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