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<div class="moz-cite-prefix">Le 23/01/2024 à 20:56, Wilco K via
gdal-dev a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:PRAPR10MB5275D700F4E4EEAFB3AED51ADF742@PRAPR10MB5275.EURPRD10.PROD.OUTLOOK.COM">
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<style type="text/css" style="display:none;">P {margin-top:0;margin-bottom:0;}</style>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">Hi,</span></div>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">why
is
<b>units=km</b> not working?</span></div>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 14pt; color: rgb(0, 0, 0);"><b><br>
</b></span></div>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 14pt; color: rgb(0, 0, 0);"><b>gdaltransform
-s_srs EPSG:4326 -t_srs "+proj=stere +lat_0=90 +lon_0=0
+lat_ts=60 +a=6378.14 +b=6356.75 +x_0=0 +y_0=0
</b></span><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 14pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"><b>+units=km" </b></span></div>
<div class="elementToProof"><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); font-weight: 400;"><br>
</span></div>
<div class="elementToProof"><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); font-weight: 400;">The
following error is returned:</span></div>
<div style="text-align: left; margin: 0px;"><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); font-weight: 400;">ERROR
1: PROJ: proj_create_operations: Source and target ellipsoid
do not belong to the same celestial body</span></div>
<div><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
<br>
</span></div>
<div class="elementToProof"><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); font-weight: 400;">Converting
+a and +b to meters and it does works:</span></div>
<div class="elementToProof"><span
style="letter-spacing: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 14pt; color: rgb(0, 0, 0);"><b>gdaltransform
-s_srs EPSG:4326 -t_srs "+proj=stere +lat_0=90 +lon_0=0
+lat_ts=60 +a=6378140 +b=6356750 +x_0=0 +y_0=0"</b></span></div>
<div><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
<br>
</span></div>
<div class="elementToProof"><span
style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">Any
ideas?</span></div>
</blockquote>
<p>Cf <a class="moz-txt-link-freetext" href="https://proj.org/en/9.3/usage/projections.html#units">https://proj.org/en/9.3/usage/projections.html#units</a> :
"Horizontal coordinate system units can be specified using the <code
class="docutils literal notranslate"><span class="pre">+units</span></code>
keyword [...] Note that this does <em>not</em> affect the units
of linear parameters such as <code
class="docutils literal notranslate"><span class="pre">+x_0</span></code>
or <code class="docutils literal notranslate"><span class="pre">+y_0</span></code>
which should always be specified in meters." . This also applies
to the +a and +b parameters. Doc enhancement filed in
<a class="moz-txt-link-freetext" href="https://github.com/OSGeo/PROJ/pull/4010">https://github.com/OSGeo/PROJ/pull/4010</a></p>
<p><br>
</p>
<p>When you specify +units=km, it just means that you wish the
output projected coordinates are expressed in km. But this doesn't
affect the units of any linear parameters of the projection
definition.<br>
</p>
<p><span style="white-space: pre-wrap">
</span></p>
<p><span style="white-space: pre-wrap">Even
</span></p>
<p><span style="white-space: pre-wrap">
</span></p>
<pre class="moz-signature" cols="72">--
<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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