[Gdal-dev] NITF ICHIPB Extension?

[Frank Warmerdam]

On Fri, 10 Dec 2004 13:53:18 -0500, William Lyons
<wlyons at prologic-inc.com> wrote:
> Frank,
> 
> I'm thinking about trying to fake a geo-transform between the two image
> spaces.  But, I'm not 100% sure what the 6 floats in the geo-transform
> really mean.  Could you enlighten me?

William, 

They represent an affine transformation.  There is a reasonable
definition in the
GetGeoTransform() call:

  http://www.gdal.org/classGDALDataset.html#a8

However, I notice the GDALRPCInfo structure (and corresponding
metadata) have fields named dfLINE_OFF, dfSAMP_OFF, dfLINE_SCALE
and dfSAMP_SCALE.  I think it would be much easier to just adjust these
if the change is just a non-rotated windowing. 

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent