[gdal-dev] Polar stereographic projection invalid definition ?

[Rousseau Lambert,Louis-Philippe (ECCC)]

Hi all,

I have an issue with a polar stereographic projection definition.

Context: I tried to open a NetCDF files in QGIS and with GDAL and it 
failed with:

  * Gdal:/ERROR 1: PROJ: proj_as_proj_string: Unsupported conversion
    method: Polar_Stereographic/
  * Qgis:/WARNING Could not reproject layer extent: Could not transform
    bounding box to taret CRS
    /

The projection fails with the previous error for both gdal and proj 
versions:

  * GDAL 3.1.3, 3.3.0
  * PROJ 7.2.0, 8.01

Test files (really any files in the folder will have the same behavior):

  * https://dd.weather.gc.ca/model_giops/netcdf/polar_stereographic/2d/00/003/CMC_giops_votemper_depth_0.5_ps5km60N_3h-mean_*{YYYYMMDDHH}*_P003.nc

I tried opening the files with an older gdal/proj version and it worked 
fine:

  * GDAL: |2.4.4, released 2020/01/08|
  * PROJ: Rel. 4.8.0, 6 March 2012

Here is the projection definition I got: /+proj=stere +lat_0=90 
+lat_ts=59.99993768695209 +lon_0=-100 +k=0.93301243 +x_0=4245000 
+y_0=5295000 +a=6371229 +b=6371229 +units=m +no_defs/

When I tried adding the projection manually in Qgis (3.20), I got the 
following error message:

/This proj projection definition is not valid://
//proj_create: lat_ts != lat_0 and k != 1 not supported for Polar 
Stereographic./

Should the projection definition be updated in the NetCDF files if this 
really is not a supported projection definition anymore, or is this a 
bug in gdal?

If this looks like a bug to you, let me know, I will open an issue on 
the gdal repo.

Thanks!

LP
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