[gdal-dev] GDAL 3.7.0 Proj 6.3.1 strange behavior when performing NAD83(EPSG:4152) to NAD83 HARN(EPSG:4269) realization transformation

[Greg Troxel]

You didn't, as far as I can tell, post the code that is not doing what
you want.  Or perhaps turn that code into a small test case program.
People reading that would be able to be more helpful, and the code
example could help others.

Proj 6.3 is quite old.   I recommend you update to the latest release
and the latest gridshift package before debugging further.   I am not a
gdal or proj maintainer, but I am packager for both, and often rant
about NAD83 and WGS84 issues.   In general, proj has a hard time dealing
reasonably with WGS84 (which you aren't at the moment), and the
transforms among the various NAD83 are complicated.  I am not the least
bit sure they are all in the epsg dataset.

You should very likely be using projinfo, and also thinking about how
you are conveying the area of applicability when setting up the
transform.