[PROJ] ETRFxx to national ETRS89 realizations (e.g. ETRS89-NLD [AGRS2010], RGF93 v2/v2b, ETRS89-HUN [ETRF2000], etc.) (was Re: Time dependency in ETRFxx to ETRFyy coordinate transformations?)

[Javier Jimenez Shaw]

Even, you are opening a can of worms… epochs.
I want to see what comes out of this ;P (if any)

On Sun, 21 Jun 2026, 23:07 Even Rouault via PROJ, <proj at lists.osgeo.org>
wrote:

> Thinking more and looking at "ETRS89-NLD [AGRS2010] to ETRF2000 (1)", I
> see it is a noop transformation, so with no time dependency...  How does
> that fit with the fact that ETRF2000 is dynamic. I see that "ETRS89-NLD
> [AGRS2010]" uses DATUM["AGRS2010 (ETRF2000)") and has
> ANCHOREPOCH[2010.5]. So I'm thinking the output coordinate when
> applying "ETRS89-NLD [AGRS2010] to ETRF2000 (1)" is at coordinate epoch
> 2010.5, right?   Shouldn't the PROJ pipeline +proj=set +v_4=2010.5 ?
>
> Same question for ETRS89-FRA [RGF93 v2] to ETRF2000 (1) and ETRS89-FRA
> [RGF93 v2b] to ETRF2000 (1) with are both no-ops. Shouln't output
> coordinate epochs be respectively 2009 and 2019 per their anchor epoch ?
>
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