[Gdal-dev] GeoTiff pixel resolution interpretation with gdalinfo

[mattia]

I have a geotiff image which outputs with gdalinfo the following
information: (The geotiff has been obtained originally from an HDF4 format)

rasdaman at mattia-desktop:/opt/rasdaman/local$ gdalinfo Area1.tif
Driver: GTiff/GeoTIFF
Size is 7103, 3947
Coordinate System is:
PROJCS["HDFLook: LINEAR",
    GEOGCS["unnamed",
        DATUM["unknown",
            SPHEROID["unnamed",6370997,0]],
        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 = (8912408.472916,7090227.412053)
Pixel Size = (694.49452741,-1000.15538912)
Corner Coordinates:
Upper Left  ( 8912408.473, 7090227.412) ( 80d 9'4.51"E, 63d45'50.32"N)
Lower Left  ( 8912408.473, 3142614.091) ( 80d 9'4.51"E, 28d15'43.99"N)
Upper Right (13845403.101, 7090227.412) (124d30'53.14"E, 63d45'50.32"N)
Lower Right (13845403.101, 3142614.091) (124d30'53.14"E, 28d15'43.99"N)
Center      (11378905.787, 5116420.752) (102d19'58.82"E, 46d 0'47.16"N)
Band 1 Block=7103x20 Type=Byte, ColorInterp=Red
Band 2 Block=7103x20 Type=Byte, ColorInterp=Green
Band 3 Block=7103x20 Type=Byte, ColorInterp=Blue


Is my interpretation correct? The pixel resolution as indicated is in
meters... Accordingly 694 meters horizontally (X res) , 1000 meters
vertically (Y res)?!?!

What is the minus sign i front of the Y res for???

What is the UNIT["degree",0.0174532925199433]], factor in this output?? can
I use it to define the resolution?? Or what is it needed for??

Final question,

Is there a stright forward way of changing the image's resolution so as to
have a quadratic one whereby resX=resY ????

Any suggestions? help?

Thanks in advance

-- 
Mattia
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20070503/0e1fe55d/attachment.html