[Gdal-dev] Irregular geolocation grid

Frank Warmerdam warmerdam at pobox.com
Wed Apr 14 10:43:21 EDT 2004

Julien Demaria wrote:
> Hi,
> I've searched about this in mailing list and found nothing :
> I would to know if GDAL architecture is adapted or can be 
> modified/adapted/improved to handle rasters
> with geolocation from an irregular grid describing lat/lon for each pixel ?
> (Maybe this is already handled in drivers such as envisat ? but I cannot 
> read Meris RR Geolocation in OpenEV or with gdalinfo...)


GDAL can transport a set of many ground control points for geolocation.  They
may be regular (as would occur with the geolocation grid from something like
Envisat) or irregular as would occur with user collected control points.
However, there are no mechanisms in GDAL to make really effective use of
large number of geolocation ground control points.  The polynomial
transformation stuff is only good up to 3rd order.  Having a huge density
of control points to feed that isn't really worthwhile.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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