[postgis-devel] Proj 9.2

[Even Rouault]

Paul,
> I was wondering why we were only seeing new proj regressions with proj 9.2 and I think it is this change in policy that is driving it. From proj.ini:
>
> ; Can be set to on so that by default the lack of a known resource files needed
> ; for the best transformation PROJ would normally use causes an error, or off
> ; to accept missing resource files without errors or warnings.
> ; This default value itself is overriden by the PROJ_ONLY_BEST_DEFAULT environment
> ; variable if set, and then by the ONLY_BEST setting that can be
> ; passed to the proj_create_crs_to_crs() method, or with the --only-best
> ; option of the cs2cs program.
> ; (added in PROJ 9.2)
> ; only_best_default = on
>
> Basically until recently proj was quietly falling back to less accurate transforms when grids were missing. Now the default policy is to complain and fail if the best transform is missing.

Actually no. The default is only_best=no and still to not complain and 
fail, but to implement the possibility of setting only_best=yes, there 
were non trivial code changes which turned to cause behaviour changes 
(including transformations to fail whereas they should have used 
dummy/ballpark transformations) that we noticed post 9.2.0 and hopefully 
most of which have been resolved with 9.2.1.

On which precise transformations do you see changes?

Even

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