[PROJ] EPSG:2163 is deprecated

[Even Rouault]

Henry,

(I've manually forwarded your post to the list, but you should subscribe to 
the mailing list in order to post here)

As far as I remember regarding the deprecation of EPSG:2163, I noticed in a 
recent EPSG release that the underlying datum of EPSG:2163 which is EPSG:4052 
"Unspecified datum based upon the Clarke 1866 Authalic Sphere" was now 
deprecated, but EPSG:2163 was still non-deprecated, which isn't very logical. 
IOGP conclusion was that EPSG:2163 had to be deprecated, and they created 
EPSG:9311 as the future proof CRS.

The automated substitution is done by GDAL 
OGRSpatialReference::ImportFromEPSG() method. I admit this may be a bit 
surprising. If I remember well, this was to emulate a past GDAL behaviour 
where some deprecated Italian CRS had an override in the .csv files GDAL 
handled to "fix" it to have an equivalent definition of the non-deprecated 
newer CRS. The cleanest way with the now PROJ mechanism was to identify the 
non-deprecated version of a deprecated CRS instead, but I can see this is not 
always desirable.

You can opt out for that automatic substituion by setting the 
OSR_USE_NON_DEPRECATED environment variable to NO

Even

> Hello, I recently updated to new versions of PROJ (7.1.1) and GDAL (3.1.3)
> on my Ubuntu machine and am experiencing some unexpected behavior when I
> work with files projected in EPSG:2163 (US National Atlas Equal Area). I do
> not experience the same issues in environments with PROJ 7.0.0 and GDAL
> 3.0.4 installed.
> 
> It seems as if EPSG:2163 has been "deprecated" or "orphaned" but I cannot
> find any information about how or why this happened. I found this request
> from Even Rouault with a recent search:
> https://apps.epsg.org/api/v1/Change/2020.020/export?format=gml
> 
> I use this projection quite often and would like to know if there is
> anything I can do to resuscitate EPSG:2163! Maybe there is some parameter I
> can set locally that would override the automatic reassignment to
> EPSG:9311? Or maybe the CRS needs updated documentation or something like
> that?
> 
> Either GDAL or PROJ (I don't know which) is attempting to redefine the
> projection of my files as EPSG:9311 which I believe has a different datum.
> 
> When I run projinfo EPSG:2163, I get this message:
> > projinfo EPSG:2163
> 
> Warning: object is deprecated
> Alternative non-deprecated CRS:
>   EPSG:9311
> 
> When I run gdalinfo on a file projected in EPSG:2163 it looks as if the
> 
> projection has been re-interpreted as EPSG:9311 already:
> >gdalinfo test.tif
> 
> Driver: GTiff/GeoTIFF
> Files: test.tif
>        test.tif.aux.xml
> Size is 49, 1336
> Coordinate System is:
> PROJCRS["NAD27 / US National Atlas Equal Area",
>     BASEGEOGCRS["NAD27",
>         DATUM["North American Datum 1927",
>             ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
>                 LENGTHUNIT["metre",1]]],
>         PRIMEM["Greenwich",0,
>             ANGLEUNIT["degree",0.0174532925199433]],
>         ID["EPSG",4267]],
>     CONVERSION["US National Atlas Equal Area",
>         METHOD["Lambert Azimuthal Equal Area (Spherical)",
>             ID["EPSG",1027]],
>         PARAMETER["Latitude of natural origin",45,
>             ANGLEUNIT["degree",0.0174532925199433],
>             ID["EPSG",8801]],
>         PARAMETER["Longitude of natural origin",-100,
>             ANGLEUNIT["degree",0.0174532925199433],
>             ID["EPSG",8802]],
>         PARAMETER["False easting",0,
>             LENGTHUNIT["metre",1],
>             ID["EPSG",8806]],
>         PARAMETER["False northing",0,
>             LENGTHUNIT["metre",1],
>             ID["EPSG",8807]]],
>     CS[Cartesian,2],
>         AXIS["easting (X)",east,
>             ORDER[1],
>             LENGTHUNIT["metre",1]],
>         AXIS["northing (Y)",north,
>             ORDER[2],
>             LENGTHUNIT["metre",1]],
>     USAGE[
>         SCOPE["unknown"],
>         AREA["USA"],
>         BBOX[15.56,167.65,74.71,-65.69]],
>     ID["EPSG",9311]]
> Data axis to CRS axis mapping: 1,2
> 
> I put some more details on this GIS StackExchange question
> <https://gis.stackexchange.com/questions/377099/deprecated-crs-epsg2163-gets
> -reinterpreted-as-another-crs-epsg9311-by-gdal>
> 
> Thank you in advance for any advice!


-- 
Spatialys - Geospatial professional services
http://www.spatialys.com