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<p>Sean,</p>
<p>thanks for the report. Support for GMT .cpt files dates back to
2010 and hasn't evolved much since. So I assume GMT .cpt format
might have changed a bit since then. I've submitted a fix in
<a class="moz-txt-link-freetext" href="https://github.com/OSGeo/gdal/pull/14595">https://github.com/OSGeo/gdal/pull/14595</a> to support new files. In
the mean time you can manually adjust your .cpt file to please
current released GDAL versions by:</p>
<p>- replacing slashed with space</p>
<p>- and removing the trailing " L"</p>
<p>Even</p>
<div class="moz-cite-prefix">Le 17/05/2026 à 22:24, Sean King via
gdal-dev a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAAaFaTknK4dWH8ncGt1DHSrxMVHm=5OAgWoO=vHgM=vm=ng5KQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">Hi folks,
<div><br>
</div>
<div>I'm using GMT version 6.6.0 and GDAL version 3.12.4. I have
several CPT files that I generated in GMT using the makecpt
command, such as: </div>
<div><br>
</div>
<div><b><i>gmt makecpt -T-120/120/10 -I -Crainbow -Z -Fr</i></b></div>
<div><br>
</div>
<div>which generates the attached file. Then, I am trying to
apply that color palette to a TIFF file using 'gdal raster
color'. The <a
href="https://gdal.org/en/stable/programs/gdaldem.html"
moz-do-not-send="true">documentation</a> states that </div>
<div><br>
</div>
<div><b><i>GMT .cpt palette files are also supported
(COLOR_MODEL = RGB only).</i></b></div>
<div><br>
</div>
<div>however, I continually get the error of </div>
<div><br>
</div>
<div><b><i>ERROR 1: No color association found in test.cpt</i></b></div>
<div><b><i><br>
</i></b></div>
<div>When I dug into the GDAL source code for the GMT CPT parser
<a
href="https://github.com/OSGeo/gdal/blob/b3f839f2515b023e4a7cf099b7ce1626ccb24eac/gcore/gdalcolortable.cpp#L744"
moz-do-not-send="true">here</a>, it really does not seem to
match up with the current implementation of GMT CPT files,
even though the GDAL feature was added in the latest release.
For instance, it uses space, comma, tab, and colon as
delimiters, but no matter what flags I use for my GMT CPT
generation, I get a backslash as the delimiter, as seen in the
attached file. There are other inconsistencies as well.</div>
<div><br>
</div>
<div>Am I missing something? I'm somewhat new to GDAL and GMT,
so I'd appreciate any advice. Also, if this feature really to
read GMT CPT files is not adequate, is there a better way to
approach this? I essentially want to colorize a .grd file
using gdal, so that I can then generate map tiles with it. I
have the rest of the pipeline figured out, but I'm having
issues with the color mapping. I wrote my own converter from
GMT CPT to GDAL color file, but it's a bit buggy/hacky. I'm
wondering if there is a more 'official' way to do this.</div>
<div><br>
</div>
<div>Thanks!</div>
<div>Sean</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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</blockquote>
<pre class="moz-signature" cols="72">--
Very grumpy about LLMs: FOSS is about increasing public capital,
not becoming enslaved to private equity of giga corporations
--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
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