[gdal-dev] gdal re-projeciton problem with Polar Stereographic projections

[Cziferszky, Andreas]

Frank, David,

thanks a lot for your comments. It took me a while to install the 1.10.0RC3 (sorry, no Linux expert).

Unfortunately I cannot reproduce the results your are getting Frank. Your gdalinfo example is actually exactly what I would hope for. But like David I am still missing the PROJCS tag and the projection details in gdalinfo (same as my original example). I also made sure that the pcs.csv file is the original one without any modifications. So I am kind of clueless here.

Just for information: I also went back to previous versions of gdal we had installed on our servers. Various versions between as early as 1.6.2 up to 1.8.1 all had at PROJCS instead of LOCAL_CS reported by gdalinfo. So something must have changed either with gdalinfo or gdalwarp starting with 1.9.x. I also compared the pcs.csv of various versions up from 1.6.2 but the entry for 3031 was the same in all - no change there.

As for your suggestion, David, using a proj4 string as the proj definition: I have tried this as well before and it seems to be a good compromise. For the image generated like thie (-t_srs "+proj=stere +lat_0=-90 +lat_ts=-71 +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs") gdalinfo is reporting
..
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["unknown",
            SPHEROID["WGS84",6378137,298.257223563],
            TOWGS84[0,0,0,0,0,0,0]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Polar_Stereographic"],
    PARAMETER["latitude_of_origin",-71],
    PARAMETER["central_meridian",0],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
..
So the projection name is missing and the EPSG code 3031 is missing - that's kind of obvious but unfortunately incomplete. ArcGIS is reporting a custom Polar Stereographic (PS) projection (which is kind of ok and is probably related to Frank's comment regarding different PS presentations) but QGIS is reporting a EPSG:4326 projection which is of course wrong - most likely because of the missing parameters.

I guess I am going to file a bug report unless you maybe have any more suggestions.

Again thanks a lot for your help.

Andreas

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