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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:#1F497D;mso-fareast-language:EN-US">A guess; the tiff is actually stored as 32 bit float so the values have decimals, and thus don’t exactly match the colour table. Maybe the Qgis layer
is set to report without decimals? <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hmm, maybe not. Something similar was reported in GIS stack a few years ago:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><a href="https://gis.stackexchange.com/questions/197660/gdaldem-exact-color-matching-fails">https://gis.stackexchange.com/questions/197660/gdaldem-exact-color-matching-fails</a><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt">From:</span></b><span lang="EN-US" style="font-size:11.0pt"> gdal-dev <gdal-dev-bounces@lists.osgeo.org>
<b>On Behalf Of </b>paul.malm@lfv.se<br>
<b>Sent:</b> May 17, 2021 12:24 AM<br>
<b>To:</b> gdal-dev@lists.osgeo.org<br>
<b>Subject:</b> [gdal-dev] gdaldem color-relief -exact_color_entry results in RGB 000<o:p></o:p></span></p>
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<pre><strong><span style="font-family:"Courier New";color:black">*** External email: Do not click on links or attachments except from trusted senders. ***<o:p></o:p></span></strong></pre>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Hi list, I’ve tried to use exact_color_entry on a DEM-tif file.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">gdaldem color-relief 55.tif colornr.cpt 55_colrel.tif -of GTiff -exact_color_entry -co COMPRESS=LZW -b 1<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Resulting in a blank rastefile (0 0 0).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">I’ve picked (info) the colors in QGIS and there are a lot of pixels in the span of the color table below and QGis is presenting the values as integers.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">It works fine with Nearest_color_entry.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Any ideas?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Kind regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">colornr.cpt looks like this:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">40 0 255 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">41 0 255 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">43 255 255 0
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">44 0 255 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">45 255 0 0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">46 255 255 0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">47 0 255 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">48 255 0 0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">49 255 255 0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">50 0 255 0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">51 0 0 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">52 0 0 255<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">53 0 0 255<o:p></o:p></span></p>
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