Even anyway answered with a bugfix. ETRS89 now has more than 40 new members, from many European countries. The change is a free days old in EPSG. Yes, the 40m difference is the geoid height in Europe.
On Sun, 22 Feb 2026, 02:22 Greg Troxel via PROJ, <[email protected]> wrote: > Javier Jimenez Shaw via PROJ <[email protected]> writes: > > > Just testing something else, I tried this transformation to go test that > > the grids are properly used. > > In master this seems to be wrong > > > > echo 52 5 0 | PROJ_DATA=data/ PROJ_NETWORK=ON ./bin/cs2cs EPSG:4326+3855 > > EPSG:7415 > > 128410.09 445806.51 -43.41 > > > > ./bin/cs2cs > > Rel. 9.8.0, March 2nd, 2026 > > > > While in the native cs2cs in Ubuntu 24.04 makes more sense. Just 20 cm > > difference between EGM2008 and NAP height. > > > > echo 52 5 0 | PROJ_NETWORK=ON cs2cs EPSG:4326+3855 EPSG:7415 > > 128410.10 445806.50 0.20 > > > > cs2cs > > Rel. 9.4.0, March 1st, 2024 > > Separately from what's being viewed as a bug, etc. WGS84 is an ensemble > with 2m error just from the ensemble. But I would then expect any wrong > answers people are complaining about to be within 2m or so. > > Am I reading this right that 0 m in EGM2008 is 20 cm in NAP? (I get it > that this is super close and we expect close since they are both trying > to match mean sea level, with the caveat that mean sea level is a > difficult concept, with EGM2008 tied to some global MSL and NAP to some > measured sea level over some period at one(?) tide gauge.) > > What I'm boggled by is -43.41 m. That feels like a geoid height, not a > difference it orthometric datum reference surface. Which suggests that > something is more seriously wrong. > > > If my tests are correct, and I had to guess, I would say it is a > > consequence of the new ETRS89 ensemble. > > Do you mean "ETRS89 recently got a new member ETRF2020"? Without really > understanding, I would expect coordinate differences between ETRF2000 > and ETRF2020 to be on the order of one to a few cm, and that this is not > able to explain a 1m delta, let along 43m. > > (Also, I think this discussion is all about NAP and not about EVRF at > all.) > _______________________________________________ > PROJ mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/proj >
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