[Gdal-dev] GeoTiff projection/transformation problem

Frank Warmerdam warmerdam at pobox.com
Tue Feb 18 11:42:18 EST 2003

Petteri Packalen wrote:
> The code in question where error occures and an example GeoTiff image is
> attached to this mail (petteri_gtiff_problem.zip). An example code
> actually does nothing useful. listgeo prints projection of output image,
> but I don't know is it completely correct. Neither IMAGINE nor ArcGIS is
> able to open output GeoTiff file correctly (projection cannot be seen),
> but when I use libgeotiff directly everything works ok and also
> projection is saved in a way IMAGINE and ArcGIS is able to read it.


OK, I have verified and fixed this problem.  It seems that Erdas is quite
picky about getting all of GeographicTypeGeoKey, GeogGeodeticDatumGeoKey,
and GeogEllipsoidGeoKey set to KvUserDefined when defining an ellipsoid
"by hand".

I have also noticed that Imagine is picking up names for the datum and
ellipsoid from their citation geo keys. Without these I get popup message
about a NULL spheroid in Imagine.

Anyways, the GDAL CVS now has an update gdal/frmts/gtiff/gt_wkt_srs.cpp that
is more Erdas compatible - and more generally correct.

I will also drop a note to Erdas making a few suggestions for the reader.

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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