[PROJ] Fwd: PROJ 9.6.0RC3

[Häkli Pasi]

Yes, we (at the National Land Survey of Finland) decided to go this way because it is not just EPSG:3067 that is affected. We have roughly 20-30 EPSG codes that would've needed a new code and we anticipated that it would've caused more harm and confusion to users.

Keeping the long story short, nothing has changed from the geodetic perspective in Finland. Finland has had the EUREF-FIN datum since 1999 and all the Finnish projected CRSs based on ETRS89 have always been linked to EUREF-FIN. Unfortunately, we did not register EUREF-FIN to the EPSG registry back then and used the ETRS89 datum ensemble instead. However, the ETRS89 datum ensemble is does not allow accurate connections to international datums and therefore we had to update the datum information. This way we can ensure correct and accurate transformations to/from Finnish CRSs.

We anticipated that also our minimum-harm-choice may cause some problems, breakage, etc but hope that these will be minimal and can be solved out.

Regards,
Pasi Häkli

From: PROJ <proj-bounces at lists.osgeo.org> On Behalf Of Javier Jimenez Shaw via PROJ
Sent: perjantai 14. maaliskuuta 2025 15.24
To: Roger.Bivand at nhh.no
Cc: proj at lists.osgeo.org
Subject: Re: [PROJ] Fwd: PROJ 9.6.0RC3

Just some context:
AFAIK (somebody from the Finnish agency may have more information), there was a long discussion between keeping the same code (changing the geographic system), or creating a new CRS in EPSG.
The former option (change the CRS) was more convenient in the sense that users do not have to use a different EPSG code. EPSG:3067 is well known, and it is essentially the same thing (of course, this is opinable). The disadvantage are the problems you are finding now.
The latter (create a new CRS) was more consistent with the principle of not changing the CRS definition, that was the rule in EPSG. The disadvantage is that people should move to the new one, having two "tween" systems. That could also be confusing.

As you can see, the first option was finally adopted.

On Fri, 14 Mar 2025 at 14:03, Roger Bivand <Roger.Bivand at nhh.no<mailto:Roger.Bivand at nhh.no>> wrote:
On Fri, 14 Mar 2025, Javier Jimenez Shaw wrote:

> You don't often get email from j1 at jimenezshaw.com<mailto:j1 at jimenezshaw.com>. Learn why this is
> important<https://aka.ms/LearnAboutSenderIdentification>

> That makes sense, because the definition of of EPSG:3067 changed. Before
> was based on ETRS89, now on EUREF-FIN.

Yes, I reported this as it may be found by others using CRS for Finland,
and linked to an issue at the geofi repo. It may be that the Comprehensive
R Archive Network (CRAN) will update to 9.6.0 shortly after release on
some platforms, which would lead to geofi failing and having 14 days to
correct - at least now the maintainer will be forewarned if they track new
issues.

Some users think that EPSG are fixed, though.

Roger


>
> On Fri, 14 Mar 2025 at 13:48, Roger Bivand via PROJ <proj at lists.osgeo.org<mailto:proj at lists.osgeo.org><mailto:proj at lists.osgeo.org<mailto:proj at lists.osgeo.org>>> wrote:
> Standard build with RC3 OK (for manual build on Fedora 41 on which RC2
> flipped to embedded resource file without this being chosen).
>
> Only one regression among 1100 R packages using PROJ/GDAL through the R
> packages sf and terra is geofi, which compares the current definition of
> EPSG:3067 with that from earlier PROJ/EPSG versions, and fails on
> topological operations checking that CRS are the same where one object is
> instantiated on-th-fly, and the one it is compared with was created and
> serialized using an earlier PROJ/EPSG version:
> https://github.com/rOpenGov/geofi/issues/52. geofi will need to condition
> on PROJ/EPSG version.
>
> Roger
>
> --
> Roger Bivand
> Emeritus Professor
> Department of Economics, Norwegian School of Economics,
> Postboks 3490 Ytre Sandviken, 5045 Bergen, Norway.
> e-mail: Roger.Bivand at nhh.no<mailto:Roger.Bivand at nhh.no><mailto:Roger.Bivand at nhh.no<mailto:Roger.Bivand at nhh.no>>
>
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--
Roger Bivand
Emeritus Professor
Department of Economics, Norwegian School of Economics,
Postboks 3490 Ytre Sandviken, 5045 Bergen, Norway.
e-mail: Roger.Bivand at nhh.no<mailto:Roger.Bivand at nhh.no>
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