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<p>Thank you for pointing out these references.</p>

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<p>Best regards,</p>

<p>Sebastian<br>

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<font size="2"><span style="font-size:11pt"><span lang="en-US">Dr. Sebastian Bullinger<br>

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<div style="margin:0"><font size="2"><span style="font-size:11pt"><span lang="en-US">Department Object Recognition</span></span></font></div>

<div style="margin:0"><font size="2"><span style="font-size:11pt"><span lang="en-US">Fraunhofer Institute of

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<div style="margin:0"><font size="2"><span style="font-size:11pt"><span lang="en-US">Optronics, Sytem Technologies and Image Exploitation IOSB</span></span></font></div>

<div style="margin:0"><font size="2"><span style="font-size:11pt">Gutleuthausstr. 1, 76275 Ettlingen, Germany</span></font></div>

<div style="margin:0"><font size="2"><span style="font-size:11pt">Phone +49 7243 992-197</span></font></div>

<div style="margin:0"><font size="2"><span style="font-size:11pt"><a href="mailto:sebastian.bullinger@iosb.fraunhofer.de" id="LPNoLP">sebastian.bullinger@iosb.fraunhofer.de</a><br>

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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Even Rouault <even.rouault@spatialys.com><br>

<b>Sent:</b> Thursday, March 25, 2021 7:15:52 PM<br>

<b>To:</b> Bullinger, Sebastian; gdal-dev@lists.osgeo.org<br>

<b>Subject:</b> Re: [gdal-dev] Computing a geo-transform with gdalwarp from a set of GCPs also rectifies the input images</font>

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<blockquote type="cite" cite="mid:dc76e49edefa4a0bbafb603fe86c91e5@iosb.fraunhofer.de">

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<div>If it is not possible to get this information, could you point out the code snippet that performs the rectification step?</div>

<div>Since GDAL's code base is quite large, it is not easy to find the appropriate location.<br>

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Entry point of the logic to compute the transformation from source pixel coordinates to target pixel coordinates<br>

<p><a class="moz-txt-link-freetext" href="https://github.com/OSGeo/gdal/blob/master/gdal/alg/gdaltransformer.cpp#L1380">https://github.com/OSGeo/gdal/blob/master/gdal/alg/gdaltransformer.cpp#L1380</a></p>

<p>And in the first step of this transformation, when using polynomial adjustment of GCPs, you'll use:<br>

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<p><a class="moz-txt-link-freetext" href="https://github.com/OSGeo/gdal/blob/master/gdal/alg/gdal_crs.cpp">https://github.com/OSGeo/gdal/blob/master/gdal/alg/gdal_crs.cpp</a><br>

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<p>Even<br>

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<p>-- </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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