On Mon, 2011-02-21 at 13:31 +0530, Chaitanya kumar CH wrote: > Zoltan, > > The creation of 0394w.tif failed. Does the process have write > permission on directory? > I note that you did not specify the -of option for nearblack. In it's > absence, nearblack creates the output file in Erdas Imagine format.
True :), regardless of the extension you specify. > > > On Sun, Feb 20, 2011 at 10:50 PM, Zoltan Szecsei > <[email protected]> wrote: > Hi Chaitanya (& all), > I tried your nearblack comment, and got: > > nearblack -white -o 0394w.tif 0394.tif > Warning 1: TIFFFetchNormalTag:ASCII value for tag > "ImageDescription" does not end in null byte > > > Warning 1: TIFFFetchNormalTag:ASCII value for tag > "ImageDescription" does not end in null byte > Warning 1: TIFFFetchNormalTag:ASCII value for tag "Software" > contains null byte in value; value incorrectly truncated > during reading due to implementation limitati > ERROR 4: Creation of file 0394w.tif failed. > > > I think I am having trouble understanding the setting/using of > nodata values. > I have now also downloaded and compiled gdal 1.8.0 (but > nearblack remained on v1.7.3) on ubuntu 10.04 LTS, and > recreated my vrt, to no improvement. > > To recap: I have 179 3*8bit RGB band aerial images that have > been orthorectified. The resulting skewness in the images has > created white slivers in the corners, and I am presuming that > these white slivers are recognised as "nodata". (My first > mistake?) > > I use the following to create a vrt: > gdalbuildvrt -addalpha -hidenodata -srcnodata "255 255 255" > -vrtnodata "0 0 0" -input_file_list files > 177_untiled_orthos_nodata_180.vrt > > Thinking that the above will tell gdalbuildvrt that, for the > input orthos, white should be recognised as 'nodata', and in > the VRT, those white pixels should be converted to black, as > nodata. > Well, as you've guessed, it didn't happen this way, and I > still have the white bits after mosaicking my VRT thus: > gdal_translate -projwin -16000 -3520650 -13000 -3525650 > 177_untiled_orthos_nodata.vrt try1.tif > > I tried re-running gdalbuildvrt specifying -vrtnodata "255 255 > 255" (to match the input ortho files) and the outside border > of my vrt turned white, but the slivers between the mosaicked > orthos were still present. > > Please can someone show me the correct way to address this > problem. > > I have included gdalinfo results for both an individual ortho, > and for the vrt itself. > > Thanks & regards, > Zoltan > > > > > > > ********************************** GDALINFO on indicidual > ORTHO **************************************** > geograph@gs0:~/vrt_177$ gdalinfo --version > GDAL 1.8.0, released 2011/01/12 > geograph@gs0:~/vrt_177$ > geograph@gs0:~/vrt_177$ > geograph@gs0:~/vrt_177$ > geograph@gs0:~/vrt_177$ > gdalinfo > /mnt/geo_lvm0/ngi_jobs/orthos_8bit/NGI_177_untiled_orthos/0003.tif > Warning 1: TIFFFetchNormalTag:ASCII value for tag > "ImageDescription" does not end in null byte > Warning 1: TIFFFetchNormalTag:ASCII value for tag "Software" > contains null byte in value; value incorrectly truncated > during reading due to implementation limitations > > > Mask Flags: PER_DATASET ALPHA > Band 4 Block=128x128 Type=Byte, ColorInterp=Alpha > geograph@gs0:~/vrt_177$ > > ******************************************************************************************************* > > > > > > > On 2011-02-16 19:39, Chaitanya kumar CH wrote: > > 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 > > <[email protected]> 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 > =========================================== > > ______________________________________________________________ > > > > > > > > > -- > Best regards, > Chaitanya kumar CH. > /tʃaɪθənjə/ /kʊmɑr/ > +91-9494447584 > 17.2416N 80.1426E > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
