still an issue Re: *cs out EPSG:3042 and *declination auto - weird interaction

[Warren Family]

Thanks Olly for getting to the bottom of this.  I'll update the DowProv 
case study to follow your suggestions. -- Patrick

On 23/10/2023 22:35, Olly Betts wrote:
> On Thu, Oct 19, 2023 at 09:06:11PM +0100, Olly Betts wrote:
>> |  o proj_factors(): make it work with projected CRS with non-metre unit and/or
>> |  northing/easting axis order (#3826)
>>
>> That patch is https://github.com/OSGeo/PROJ/pull/3826
>>
>> I suspect just adding the code to select a consistent axis order will
>> solve this.  If not we may be able to copy code from that patch.
> It turns out copying code from the patch is tricky as it seems to use
> PROJ functions which aren't exported in their public API, but just
> normalising the output order like we already do when converting
> coordinates seems to fix this for older PROJ.
>
> I've converted your reduced reproducer into a testcase in the testsuite
> and package builds run the testsuite so once I've made a release and
> backported the packages we can be confident that this is fixed.  The
> only wrinkle is that this new testcase is failing on macOS in CI due
> to the coordinates of the fixed point converting differently by
> (-0.28,1.41,0.00) (metres).  Homebrew currently provides the same
> upstream PROJ version as Debian so I'm not sure what's up.  This seems
> to be unrelated to your bug.
>
> I'll try to resolve this and make a release fairly soon but if you're
> affected by this then if you're able to move `*cs out` after
> `*declination auto` that should provide a crude workaround (you'll end
> up without grid convergence correction for now though).  This workaround
> will function correctly and correct for grid convergence with the next
> release.
>
> Another way to work around it is to pick a different output coordinate
> system which isn't affected by this issue.  If cavern sees `*cs out`
> more than once it just uses the first it sees so you can use a
> wrapper .svx file to use a different output coordinate system without
> having to change your data, e.g. mycave-utm.svx with:
>
>      *cs out UTM30N
>      ; Any cs out in mycave.svx or files it includes will be ignored.
>      *include mycave.svx
>
> Cheers,
>      Olly