[FWTools] ASTER GDEM conversion to stereographic

Noel Gourmelen N.Gourmelen at leeds.ac.uk
Thu Mar 24 09:51:47 EST 2011


Hello, 

I am converting a latitude longitude ASTER GDEM to polar stereographic as follow:

	gdalwarp -s_srs "+proj=longlat" -t_srs "+proj=stere +lat_0=90 +lat_ts=70 +lon_0=0" N79W063.tif N79W063_stereo.tif
Processing input file N79W063.tif.
Using internal nodata values (eg. nan) for image N79W063.tif.
0...10...20...30...40...50...60...70...80...90...100 - done.

The output coordinates are off, while I m expecting values in the range of -517777.16712146 -1016194.90770327; the output coordinates are  ~ -121.792, -12330234.526

Any idea of what I am doing wrong?

Thank you.

N

	gdalinfo N79W063_stereo.tif
Driver: GTiff/GeoTIFF
Files: N79W063_stereo.tif
Size is 3601, 3601
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["unnamed ellipse",
        DATUM["unknown",
            SPHEROID["unnamed",6378137,298.2572235629972]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Polar_Stereographic"],
    PARAMETER["latitude_of_origin",70],
    PARAMETER["central_meridian",0],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-121.792085924375542,-12330234.526312625035644)
Pixel Size = (0.000537000916159,-0.000537000916159)
Metadata:
  AREA_OR_POINT=Area
Image Structure Metadata:
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (    -121.792,-12330234.526) (  0d 0'2.04"W,  0d 0'2.60"N)
Lower Left  (    -121.792,-12330236.460) (  0d 0'2.04"W,  0d 0'2.57"N)
Upper Right (    -119.858,-12330234.526) (  0d 0'2.01"W,  0d 0'2.60"N)
Lower Right (    -119.858,-12330236.460) (  0d 0'2.01"W,  0d 0'2.57"N)
Center      (    -120.825,-12330235.493) (  0d 0'2.02"W,  0d 0'2.59"N)
Band 1 Block=3601x1 Type=Float32, ColorInterp=Gray



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