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<p class="MsoNormal"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I am following the FAQ “How to create or modify an image color table?” from
<a href="https://trac.osgeo.org/gdal/wiki/FAQRaster">https://trac.osgeo.org/gdal/wiki/FAQRaster</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I took out the palette from existing tiff file into VRT and I would like to change alpha value of the first input from 255 into 0.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I had originally this:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><VRTDataset rasterXSize="734" rasterYSize="565"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <VRTRasterBand dataType="Byte" band="1"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <ColorInterp>Palette</ColorInterp><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <ColorTable><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <Entry c1="255" c2="255" c3="255" c4="255" /><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <Entry c1="0" c2="0" c3="0" c4="255" /><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> …<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Then I edited the VRT into<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <ColorTable><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <Entry c1="60" c2="255" c3="255" c4="0" /><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <Entry c1="0" c2="0" c3="0" c4="255" /><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">…<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Then I executed<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">gdal_translate fixed_palette.vrt fixed palette.tif<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">However, the result is not exactly what I hoped for:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Band 1 Block=734x11 Type=Byte, ColorInterp=Palette<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> Color Table (RGB with 256 entries)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> 0: 60,255,255,255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> 1: 0,0,0,255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The value “60” for the red band is taken from my edited palette but my edited alpha value is not honored. Am I doing something wrong?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
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