<div dir="ltr"><div>Hi,</div><div><br></div><div><span lang="en"><span><span> The EPSG:9624 method is a 2D transformation, so the translation vector has only two elements and the rotation matrix has only two rows and two columns.</span></span> <span><span><br></span></span></span></div><div><span lang="en"><span><span> I<span lang="en"><span><span>n the description of the EPSG method, the algebraic expression is found but in the documentation of the affine transformation in PROJ it is expressed in its matrix form.</span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span> <span lang="en"><span><span>The equivalences are as follows:</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span><br></span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>A0 = +xoff</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>A1 = +s11</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>A2 = +s12</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>B0 = +yoff</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>B1 = +s21<br></span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>B2 = +s22</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span><br></span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span><br></span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>Regards,</span></span></span></span></span></span></span></span></span></div><div><span lang="en"><span><span><span lang="en"><span><span><span lang="en"><span><span>Gabriel<br></span></span></span></span></span></span></span></span></span></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">El mié, 1 jun 2022 a la(s) 08:03, Torill Kjøsnes Gabrielsen (<a href="mailto:torill.kjosnes@gmail.com" target="_blank">torill.kjosnes@gmail.com</a>) escribió:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">Hi,</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"> </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">I have an engineering crs that I would like to transform
with an affine transformation. </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"> </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">The transformation for the crs is defined in 9624<span lang="EN-US">: </span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><a href="https://epsg.org/coord-operation-method_9624/Affine-parametric-transformation.html" style="color:rgb(5,99,193)" target="_blank">https://epsg.org/coord-operation-method_9624/Affine-parametric-transformation.html</a> <span lang="EN-US"></span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"> </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">The coordinate transformation parameter values are:</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">A0 = 82357.457 metres</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">A1 = 0.304794369</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">A2 = 0.000015417425</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">B0 = 28091.324 metres</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">B1 = -0.000015417425</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">B2 = 0.304794369</p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"> </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="EN-US">Is there anyone
who can help me address w</span>hich parameters correspond to <span lang="EN-US">those</span> defined in PROJ affine? </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"> </p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">A0 <span lang="EN-US">= </span>+xoff<span lang="EN-US">? </span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="EN-US">A1 = +s11?</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="EN-US">A2 = ?</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif">B0<span lang="EN-US"> =</span>
+yoff<span lang="EN-US">?</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="NO-BOK">B1 = </span>+s22<span lang="NO-BOK">?</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="NO-BOK">B2 = ?</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="NO-BOK"> </span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="NO-BOK">Regards,</span></p>
<p class="MsoNormal" style="margin:0cm;font-size:12pt;font-family:Calibri,sans-serif"><span lang="NO-BOK">Torill Gabrielsen</span></p></div>
_______________________________________________<br>
PROJ mailing list<br>
<a href="mailto:PROJ@lists.osgeo.org" target="_blank">PROJ@lists.osgeo.org</a><br>
<a href="https://lists.osgeo.org/mailman/listinfo/proj" rel="noreferrer" target="_blank">https://lists.osgeo.org/mailman/listinfo/proj</a><br>
</blockquote></div>