[PROJ] ballpark transformation ITRF2014 -> CH1903+

[Javier Jimenez Shaw]

Ouch.

Thanks Even for the response.

I could not expect that such transformation was not published.
Now I see that WGS84(G1762) to ETRS89 goes through WGS84, with an accuracy
of 3m. Looks like Europe is isolated from the World (in a datum accurate
transformation sense ;)

Cheers.
.___ ._ ..._ .. . ._.  .___ .. __ . _. . __..  ... .... ._ .__
Entre dos pensamientos racionales
hay infinitos pensamientos irracionales.



On Thu, 29 Apr 2021 at 12:14, Even Rouault <even.rouault at spatialys.com>
wrote:

>
> There is a transformation from ETRS89 to CH1903+ with 0.1m accuracy. Why
> is not using it (nested with ITRF2014 -> ETRS89)?
>
> Because there is no transformation registered between ITRF2014 and ETRS89
> (*), so there's no reason to use the ETRS89 intermediate because the result
> would have a unknown accuracy.
>
> (*) actually if you do "projinfo -s "ITRF2014"  -t ETRS89 --spatial-test
> intersects", you'll see that it manages to compute transformation paths for
> Nordic countries, but this is already using an intermediate ETRF2014 pivot,
> so PROJ logic wouldn't be able to do ITRF2014 -> ETRF2014 -> .... -> ETRS89
> -> CH1903+, and anyway the area of use aren't compatible
> --
>
> http://www.spatialys.com
> My software is free, but my time generally not.
>
>
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