[PROJ] ballpark transformation ITRF2014 -> CH1903+

[Even Rouault]

> 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

-- 

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