On 09/22/2010 08:36, Rahkonen Jukka wrote:
Hi,

For sure the original image is not in EPSG:4326. You can guess it from the 
coordinates, for example
  Origin = (-8563840.575678950175643,6466755.550653258338571)
EPSG:4326 is naturally between -90,90 and -180,180. There does read
AUTHORITY["EPSG","4326"]] in one place of the gdalinfo report, but it is in the 
section that tells the datum or the projection.

I am not sure what the right projection could be, but I found this projection 
wiht the same lookin parametrers
from my Mapserver proj directory:
# WGS 84 / Antarctic Polar Stereographic
<3031>  +proj=stere +lat_0=-90 +lat_ts=-71 +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 
+datum=WGS84 +units=m +no_defs<>

If this is correct, you do not need to reproject at all because your image is 
already in EPSG:3031.

-Jukka Rahkonen-

Thanks for the clarification, looks like I misunderstood the output of gdalinfo..!

Julien


-----Alkuperäinen viesti-----
Lähettäjä: [email protected]
[mailto:[email protected]] Puolesta Julien Cigar
Lähetetty: 21. syyskuuta 2010 22:09
Vastaanottaja: [email protected]
Aihe: [mapserver-users] reprojection

   Hello,

I'm trying to re-project a RASTER layer but without success so far.
I have the following TIFF file:

m...@mordor:/home/mage/gis % gdalinfo antarctica_sthn_ocean.tiff
Driver: GTiff/GeoTIFF
Files: antarctica_sthn_ocean.tiff
Size is 12216, 9094
Coordinate System is:
PROJCS[" Projection Name = WGS_1984_Stereographic_South_Pole Units =
meters GeoTIFF Units = meters",
      GEOGCS["WGS 84",
          DATUM["WGS_1984",
              SPHEROID["WGS 84",6378137,298.257223563,
                  AUTHORITY["EPSG","7030"]],
              AUTHORITY["EPSG","6326"]],
          PRIMEM["Greenwich",0],
          UNIT["degree",0.0174532925199433],
          AUTHORITY["EPSG","4326"]],
      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"]]]
Origin = (-8563840.575678950175643,6466755.550653258338571)
Pixel Size = (1420.390210742724321,-1420.394765779645695)
Metadata:
    TIFFTAG_XRESOLUTION=900
    TIFFTAG_YRESOLUTION=900
    TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
    AREA_OR_POINT=Area
Image Structure Metadata:
    INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (-8563840.576, 6466755.551) ( 52d56'33.71"W,  8d
9'27.23"S)
Lower Left  (-8563840.576,-6450314.449) (126d59'13.87"W,
8d12'36.90"S)
Upper Right ( 8787646.239, 6466755.551) ( 53d39'3.45"E,  7d12'35.07"S)
Lower Right ( 8787646.239,-6450314.449) (126d16'45.99"E,
7d15'38.97"S)
Center      (  111902.832,    8220.551) ( 85d47'54.65"E, 88d58'2.41"S)
Band 1 Block=256x256 Type=Byte, ColorInterp=Red
    Overviews: 6108x4547, 3054x2274, 1527x1137, 764x569
    Metadata:
      LAYER_TYPE=athematic
Band 2 Block=256x256 Type=Byte, ColorInterp=Green
    Overviews: 6108x4547, 3054x2274, 1527x1137, 764x569
    Metadata:
      LAYER_TYPE=athematic
Band 3 Block=256x256 Type=Byte, ColorInterp=Blue
    Overviews: 6108x4547, 3054x2274, 1527x1137, 764x569
    Metadata:
      LAYER_TYPE=athematic

If I understood well the output of gdalinfo, the projection
seems to be
EPSG:4326.
Now I want to re-project this to EPSG:3031.
I tried with the following MAP file :

MAP
      NAME "antarctic"
      STATUS ON
      SIZE 600 400
      EXTENT -8563840.576 -6450314.449 8787646.239 6466755.551
      IMAGECOLOR 255 255 255

      PROJECTION
          "init=epsg:3031"
      END

      OUTPUTFORMAT
          NAME png
          DRIVER "GD/PNG"
          MIMETYPE "image/png"
          IMAGEMODE RGBA
          EXTENSION "png"
      END

      LAYER
          NAME "ocean"
          TYPE RASTER
          STATUS DEFAULT
          DATA antarctica_sthn_ocean.tiff
          PROJECTION
              "init=epsg:4326"
          END
      END
END

... but all what I get is a gray 600x400 PNG image ...

Any idea what could be the problem ?

Thanks,
Julien



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