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<p>Because of some problems with GDAL 1.7.0b2 in FWTools 2.4.7 I
upgraded to GDAL 1.11.0 in the latest OSGeo4W distro. This solved
some issues I had, but introduced a really annoying one and what
ever I do I can't get rid off it. I hope someone can help me out.
If BTW I try to go back to GDAL 1.7.0b2 with FWTools the problem
is still there, so I guess it's a (new) driver/DLL update issue. </p>
<p>My problem looks exactly like this post... <a
href="http://gis.stackexchange.com/questions/101393/gdal-tif-to-jpg-creates-dark-image">GDAL
TIF to JPG Creates Dark Image</a> Only that I don't use JPG. And
I use GDALwarp. And not all target files have the problem. Most
target files look OK. And I only see it with Aerial Photo like
sources. With vector like raster sources I don't see the problem.
So when reading the other post I thought it had to do with a
mask/alpha channel or something, but I can't see this in the
source. And whatever option I test, the problem remains.<br>
</p>
<p>I already created a post here : <a class="moz-txt-link-freetext"
href="http://gis.stackexchange.com/questions/114526/gdalwarp-creates-darker-target-image-sometimes">http://gis.stackexchange.com/questions/114526/gdalwarp-creates-darker-target-image-sometimes</a><br>
But I had no final answer... And I think this is the right place
to ask. <br>
</p>
<p>Here are two screenshots. One from the source (Tiff) and one from
a intersection of four target files (Tiff or BMP)<br>
</p>
<p>Section of Source : <a
href="https://www.dropbox.com/s/gy2tu0h8dufv41o/Source.jpg?dl=0"
rel="nofollow">https://www.dropbox.com/s/gy2tu0h8dufv41o/Source.jpg?dl=0</a></p>
<p>Intersection of four Target files : <a
href="https://www.dropbox.com/s/av7mdj8ivx3zgsl/Target.jpg?dl=0"
rel="nofollow">https://www.dropbox.com/s/av7mdj8ivx3zgsl/Target.jpg?dl=0</a></p>
<p>The source I use is 8bit/channel RGB JPEG. And the merged Tiff is
8bit/channel RGB. <br>
I tested almost all options in multiple actions in my workflow. So
cutting the source with gdaltranslate in smaller parts for
editing. Building a VRT with gdalbuildvrt and cutting into final
parts with gdalwarp which will show the problem.</p>
<p>I started with the -b 1 -b 2 -b 3 option in my gdalbuildvrt
action, but GDAL crashes here... (?) I also tested other options
that might have something to do with the problem... -nomd -co
ALPHA=YES/No -co PHOTOMETRIC=RGBA/RGB -setci, you name it... </p>
<p>I checked good and bad source and target areas with gdalcompare
and gdalinfo, but I saw nothing strange... </p>
<p>I'm now thinking of resetting GDAL driver settings if that is
possible..(?)</p>
<p>Has anyone seen this before? Can anyone give me a hint..?</p>
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