[QGIS-Developer] issue transforming coords from EPSG:4258 'ETRS89' to 4326

Even Rouault even.rouault at spatialys.com
Mon Mar 21 09:04:43 PDT 2022


Alessandro,

the truth (and sometimes issues) is in projinfo:

$ projinfo -s EPSG:4258 -t EPSG:4326
Candidate operations found: 1
-------------------------------------
Operation No. 1:

EPSG:1149, ETRS89 to WGS 84 (1), 1.0 m, Europe - onshore and offshore: 
Albania; Andorra; Austria; Belgium; Bosnia and Herzegovina; Bulgaria; 
Croatia; Cyprus; Czechia; Denmark; Estonia; Faroe Islands; Finland; 
France; Germany; Gibraltar; Greece; Hungary; Ireland; Italy; Kosovo; 
Latvia; Liechtenstein; Lithuania; Luxembourg; Malta; Moldova; Monaco; 
Montenegro; Netherlands; North Macedonia; Norway including Svalbard and 
Jan Mayen; Poland; Portugal; Romania; San Marino; Serbia; Slovakia; 
Slovenia; Spain; Sweden; Switzerland; United Kingdom (UK) including 
Channel Islands and Isle of Man; Vatican City State.

PROJ string:
+proj=noop

WKT2:2019 string:
COORDINATEOPERATION["ETRS89 to WGS 84 (1)",
     VERSION["EPSG-eur"],
     SOURCECRS[
         GEOGCRS["ETRS89",
             ENSEMBLE["European Terrestrial Reference System 1989 ensemble",
                 MEMBER["European Terrestrial Reference Frame 1989"],
                 MEMBER["European Terrestrial Reference Frame 1990"],
                 MEMBER["European Terrestrial Reference Frame 1991"],
                 MEMBER["European Terrestrial Reference Frame 1992"],
                 MEMBER["European Terrestrial Reference Frame 1993"],
                 MEMBER["European Terrestrial Reference Frame 1994"],
                 MEMBER["European Terrestrial Reference Frame 1996"],
                 MEMBER["European Terrestrial Reference Frame 1997"],
                 MEMBER["European Terrestrial Reference Frame 2000"],
                 MEMBER["European Terrestrial Reference Frame 2005"],
                 MEMBER["European Terrestrial Reference Frame 2014"],
                 ELLIPSOID["GRS 1980",6378137,298.257222101,
                     LENGTHUNIT["metre",1]],
                 ENSEMBLEACCURACY[0.1]],
             PRIMEM["Greenwich",0,
                 ANGLEUNIT["degree",0.0174532925199433]],
             CS[ellipsoidal,2],
                 AXIS["geodetic latitude (Lat)",north,
                     ORDER[1],
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
             ID["EPSG",4258]]],
     TARGETCRS[
         GEOGCRS["WGS 84",
             ENSEMBLE["World Geodetic System 1984 ensemble",
                 MEMBER["World Geodetic System 1984 (Transit)"],
                 MEMBER["World Geodetic System 1984 (G730)"],
                 MEMBER["World Geodetic System 1984 (G873)"],
                 MEMBER["World Geodetic System 1984 (G1150)"],
                 MEMBER["World Geodetic System 1984 (G1674)"],
                 MEMBER["World Geodetic System 1984 (G1762)"],
                 MEMBER["World Geodetic System 1984 (G2139)"],
                 ELLIPSOID["WGS 84",6378137,298.257223563,
                     LENGTHUNIT["metre",1]],
                 ENSEMBLEACCURACY[2.0]],
             PRIMEM["Greenwich",0,
                 ANGLEUNIT["degree",0.0174532925199433]],
             CS[ellipsoidal,2],
                 AXIS["geodetic latitude (Lat)",north,
                     ORDER[1],
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
             ID["EPSG",4326]]],
     METHOD["Geocentric translations (geog2D domain)",
         ID["EPSG",9603]],
     PARAMETER["X-axis translation",0,
         LENGTHUNIT["metre",1],
         ID["EPSG",8605]],
     PARAMETER["Y-axis translation",0,
         LENGTHUNIT["metre",1],
         ID["EPSG",8606]],
     PARAMETER["Z-axis translation",0,
         LENGTHUNIT["metre",1],
         ID["EPSG",8607]],
     OPERATIONACCURACY[1.0],
     USAGE[
         SCOPE["(null/copy) Approximation for medium and low accuracy 
applications assuming equality between plate-fixed static and 
earth-fixed dynamic CRSs, ignoring static/dynamic CRS differences."],
         AREA["Europe - onshore and offshore: Albania; Andorra; Austria; 
Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czechia; 
Denmark; Estonia; Faroe Islands; Finland; France; Germany; Gibraltar; 
Greece; Hungary; Ireland; Italy; Kosovo; Latvia; Liechtenstein; 
Lithuania; Luxembourg; Malta; Moldova; Monaco; Montenegro; Netherlands; 
North Macedonia; Norway including Svalbard and Jan Mayen; Poland; 
Portugal; Romania; San Marino; Serbia; Slovakia; Slovenia; Spain; 
Sweden; Switzerland; United Kingdom (UK) including Channel Islands and 
Isle of Man; Vatican City State."],
         BBOX[32.88,-16.1,84.73,40.18]],
     ID["EPSG",1149],
     REMARK["ETRS89 and WGS 84 are realizations of ITRS coincident to 
within 1 metre. This transformation has an accuracy equal to the 
coincidence figure."]]

So basically ETRS89 and WGS 84 are considered the same with a 1 metre 
accuracy when considering the generic/datum ensemble versions of 
EPSG:4258 and EPSG:4326. You might possibly get time-dependent 
transformations if considering one of the ETRFxxxx realization and a WGS 
84 (Gyyyy) / ITRFzzzz realization instead.

Even

Le 21/03/2022 à 16:56, Alessandro Pasotti via QGIS-Developer a écrit :
> Hi,
>
> I'm not sure if this is a local issue on my dev env or if it is a real 
> issue, I have a raster layer in EPSG:4258 ('ETRS89') from copernicus 
> and the project's CRS is 4326, the transformation silently fails and 
> the raster is not reprojected.
>
> The issue can be reproduced from the console too:
>
> ct = QgsCoordinateTransform(QgsCoordinateReferenceSystem(4258), 
> QgsCoordinateReferenceSystem(4326), 
> QgsProject.instance().transformContext())
>
> ct.transformBoundingBox(QgsRectangle(4153600, 1296000, 5000000, 2000000))
>
> ct.isValid()
>
> True
>
> Result:
>
> <QgsRectangle: 4153600 1296000, 5000000.00000001396983862 
> 1999999.99999999720603228>
>
> Any ideas?
>
>
> -- 
> Alessandro Pasotti
> QCooperative: www.qcooperative.net <https://www.qcooperative.net>
> ItOpen: www.itopen.it <http://www.itopen.it>
>
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-- 
http://www.spatialys.com
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