Ralf, Try the -addalpha and -srcnodata options in gdalbuildvrt ( http://www.gdal.org/gdalbuildvrt.html) to generate a VRT file to represent your files, individually or combined. Mention the RGB values of the white pixels as -srcnodata values. This will add an alpha band to your images and makes all white pixels transparent.
Run gdal_retile.py using the vrt files. 2010/2/4 Ralf Wagner <r...@globema.pl> > Hello, > I am creating image pyramid from a bunch of color GeoTIFF files using > "gdal_retile" tool. I have managed to generate pyramid but unfortunately > there is a problem - my GeoTIFFs maps overlap and have white margins > around and I am unable to force GDAL to treat white color as transparent > to avoid covering maps by these margins. I have tried all ideas I could > imagine but to no avail. So my question is: how to tweak "gdal_retile" > to get white color treated as transparent during merging? > I am using GDAL 1.6 on Windows. Any help will be very, very appreciated > - thank you. > > -- > Ralf Wagner > > > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. /tʃaɪθənjə/ /kʊmɑr/ +91-9848167848 17.241582N 80.142635E
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