Thank you for your prompt answer.
Actually, I was experimenting with VRT files trying to fight this
"transparency" problem. I have failed, but probably my way of setting
transparency for VRT files was wrong - I had been setting 'c4' value
(Alpha) for 'white' entry in color table in my VRT files to '0'. It
didn't work. But if you are saying that this is way to go, I will try to
do more experiments (and I will dig deeper into VRT format) .
Best regards,
Ralf Wagner
Chaitanya kumar CH pisze:
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 <[email protected] <mailto:[email protected]>>
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
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--
Ralf Wagner
Globema Sp. z o.o., ul. Rostafińskich 4, 02-593 Warszawa, Poland
tel. (+48) 22 848 73 13, fax (+48) 22 848 68 83
www.globema.com.pl <http://www.globema.com.pl>
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