[gdal-dev] gdalwarp and the geos projection

[Andrew Chamberlain]

Hi All,

Just wondering if anyone can help.  Apologies if this is the wrong 
mailing list, but I couldn't find any other for GDAL users.

I'm using gdalwarp to project an image from Plate Carree (proj=eqc) to 
Geostationary Satellite projection (proj=geos), and I'm finding that the 
east and west edges of the resulting Earth-disk are being cut off (at 
the sides of the containing image).  I would estimate the clipping to be 
~100 pixels on each side (the overall width is 3700).

The source image has the projection details given below, and the command 
I'm using is:

  gdalwarp -t_srs '+proj=geos +lon_0=0.0 +h=745331460 +x_0=0.0 +y_0=0.0' 
-ts 3700 3700 source_eqc.tif dest_geos.tif

Has anyone seen this problem before with the geos projection?  When I 
try with the ortho projection, the full Earth disk is rendered.

Andy

-----------------------------------------------------

Size is 16384, 8192
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["unnamed",
        DATUM["unknown",
            SPHEROID["unretrievable - using WGS84",6378137,298.257223563]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Equirectangular"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",0],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-20036285.350299999117851,10018754.171399999409914)
Pixel Size = (2445.835614050000004,-2445.835614050000004)
Metadata:
  AREA_OR_POINT=Area
Corner Coordinates:
Upper Left  (-20036285.350,10018754.171) (  0d 0'0.01"E, 90d 0'0.00"N)
Lower Left  (-20036285.350,-10017531.179) (179d59'20.45"W, 89d59'20.71"S)
Upper Right (20036285.350,10018754.171) (  0d 0'0.01"E, 90d 0'0.00"N)
Lower Right (20036285.350,-10017531.179) (179d59'20.45"E, 89d59'20.71"S)
Center      (      -0.000,     611.496) (  0d 0'0.00"W,  0d 0'19.91"N)