[PROJ] Problems with last EPSG update in Germany

[Even Rouault]

Le 29/04/2023 à 19:58, Javier Jimenez Shaw a écrit :
> Thanks Even.
>
> Yes, I will contact BKG.
>
> I was thinking on another option: defining a Helmert transformation 
> between ETRS89/DREF91/2016 and ETRS89, (probably with 0,0,0 params) 
> and some (in)accuracy, to "connect" the new system with the old ones. 
> Otherwise the "new" systems and the "old" ones are disconnected and 
> only ballpark transformations are possible. Something like 
> https://epsg.org/transformation_9703/ETRF2000-PL-to-ETRS89-1.html for 
> Poland. (https://epsg.org/search/by-name/?query=ETRF2000-PL sounds 
> very similar to 
> https://epsg.org/search/by-name?searchedTerms=ETRS89%2FDREF91%2F2016 
> but without that "link" to the "old" systems).
> What do you think about this? Would it work?

Yes that also crossed through my mind. I believe it should work (but 
beware of the limitations of PROJ inference logic of guessing at most a 
single intermediate CRS, but for doing WGS84 -> ETRS89 -> 
ETRS89/DREF91/2016, that should work). You might simulate that 
beforehand by creating such a Helmert transformation.


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