[PROJ] Extents of ETRS89 UTM zones

[Javier Jimenez Shaw]

Hi.

Last March I wrote to EPSG telling that the areas of the UTM zones in
ETRS89 were a bit strange (see the image attached).
You can see them for PROJ 9.4.1 in
https://crs-explorer.proj.org/?searchText=etrs89%20utm%20-dref%20--%20-srb&ignoreWorld=false&allowDeprecated=false&authorities=EPSG&activeTypes=PROJECTED_CRS&map=osm&v=9.4.1

(just select the checkboxes in the area of use for all of them)

They addressed the issue now in EPSG v11.009 (already released).
The solution includes two usage sections per CRS, as you can see for
example in https://epsg.org/crs_25834/ETRS89-UTM-zone-34N.html . These two
areas of use can be different (in north and south limits).
One for "Engineering survey, topographic mapping." and another for
"Pan-European conformal mapping at scales larger than 1:500,000." If I
understood correctly, the former includes the countries that have such CRS
as an "oficial" system. You can see in the map in epsg.org for instance how
Croatia in included, but not Hungary. The later is usually bigger, to
include ETRF.

Be careful if your library or application does not consider the option of
having more than one area of use per CRS. You may lose some data.

Cheers,
Javier

PS those changes should be included in the next release of PROJ, 9.5.0
PS2 In previous versions of EPSG and PROJ there were already few CRSs with
two areas of use, like https://epsg.org/crs_5897/VN-2000-TM-3-zone-482.html
(in case you want to test your behaviour now)

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