[gdal-dev] Cannot set transparent color for GeoTIFFs processed by gdal_retile

[Chaitanya kumar CH]

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 <rpw at 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
>
>
>
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-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9848167848
17.241582N 80.142635E
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