Zoltan, Have you tried the nearblack GDAL utility on the original 176 images? http://www.gdal.org/nearblack.html
On Wed, Feb 16, 2011 at 5:25 PM, Zoltan Szecsei <zolt...@geograph.co.za>wrote: > On 2011-02-16 12:20, Zoltan Szecsei wrote: > >> Hi All, >> I've built a vrt with 176 images. >> >> I now need to mosaic this whole area into roughly 5 x 5 ortho images. >> >> How can I force the white edges into background of the overlapping orthos? >> I'm a little cautious of simply (finding a way to) making "white" >> transparent as it is only the white on the edges that need to be >> backgrounded. >> > > Hi again, > Since the above post, I have tried different ways to set nodata, but to no > avail - I still get the white edges: > (see jpeg sent with my original post) > > gdalbuildvrt -addalpha -hidenodata -input_file_list files > 177_untiled_orthos_nodata.vrt > gdalbuildvrt -srcnodata "0 0 0" -addalpha -hidenodata -input_file_list > files 177_untiled_orthos_blk.vrt > gdalbuildvrt -srcnodata "255 255 255" -addalpha -hidenodata > -input_file_list files 177_untiled_orthos_white.vrt > > How should I be masking out the nodata (or even white pixels) so that when > I mosaic a bunch of tiffs together, I dont get the white stripes in the > resulting image? > > Using GDAL 1.7.3, released 2010/11/10 on Ubuntu 10.04 > Viewing with Quantum GIS - 1.6.0-Trunk on Ubuntu 10.04 (same box). > ...but running the whole lot in xterms with Xming & putty from my WinVista > box. > > > Regards, > > Zoltan > > > > > -- > > =========================================== > Zoltan Szecsei PrGISc [PGP0031] > Geograph (Pty) Ltd. > P.O. Box 7, Muizenberg 7950, South Africa. > > 65 Main Road, Muizenberg 7945 > Western Cape, South Africa. > > 34° 6'16.35"S 18°28'5.62"E > > Tel: +27-21-7884897 Mobile: +27-83-6004028 > Fax: +27-86-6115323 www.geograph.co.za > =========================================== > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1204 / Virus Database: 1435/3446 - Release Date: 02/15/11 > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. /tʃaɪθənjə/ /kʊmɑr/ +91-9494447584 17.2416N 80.1426E
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