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<div class="moz-cite-prefix">Le 29/04/2021 à 15:22, Greg Troxel a
écrit :<br>
</div>
<blockquote type="cite" cite="mid:rmir1itql7r.fsf@s1.lexort.com">
<pre class="moz-quote-pre" wrap="">
Javier Jimenez Shaw <a class="moz-txt-link-rfc2396E" href="mailto:j1@jimenezshaw.com"><j1@jimenezshaw.com></a> writes:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">I could not expect that such transformation was not published.
Now I see that WGS84(G1762) to ETRS89 goes through WGS84, with an accuracy
of 3m. Looks like Europe is isolated from the World (in a datum accurate
transformation sense ;)
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
It seems to be quite published (by an author whose name will be quite
familiar to followers of ITRF). It seems that it is merely not
expressed in the EPSG database.
<a class="moz-txt-link-freetext" href="http://etrs89.ensg.ign.fr/pub/EUREF-TN-1.pdf">http://etrs89.ensg.ign.fr/pub/EUREF-TN-1.pdf</a></pre>
</blockquote>
<p>Actually the data from table 1, 2 and 3 of this paper is in EPSG.
But you need to invoke the precise ETRFxx frame, not just the
generic ETRS89<br>
</p>
<p>$ projinfo -s ETRF89 -t ITRF89 -o PROJ -q<br>
+proj=pipeline<br>
+step +proj=axisswap +order=2,1<br>
+step +proj=unitconvert +xy_in=deg +xy_out=rad<br>
+step +proj=cart +ellps=GRS80<br>
+step +inv +proj=helmert +x=0 +y=0 +z=0 +rx=0 +ry=0 +rz=0 +s=0
+dx=0 +dy=0<br>
+dz=0 +drx=0.00011 +dry=0.00057 +drz=-0.00071 +ds=0
+t_epoch=1989<br>
+convention=position_vector<br>
+step +inv +proj=cart +ellps=GRS80<br>
+step +proj=unitconvert +xy_in=rad +xy_out=deg<br>
+step +proj=axisswap +order=2,1</p>
<p>$ projinfo -s ETRF2014 -t ITRF2014 -o PROJ -q<br>
+proj=pipeline<br>
+step +proj=axisswap +order=2,1<br>
+step +proj=unitconvert +xy_in=deg +xy_out=rad<br>
+step +proj=cart +ellps=GRS80<br>
+step +inv +proj=helmert +x=0 +y=0 +z=0 +rx=0.001785
+ry=0.011151 +rz=-0.01617<br>
+s=0 +dx=0 +dy=0 +dz=0 +drx=8.5e-05 +dry=0.000531
+drz=-0.00077 +ds=0<br>
+t_epoch=2010 +convention=position_vector<br>
+step +inv +proj=cart +ellps=GRS80<br>
+step +proj=unitconvert +xy_in=rad +xy_out=deg<br>
+step +proj=axisswap +order=2,1</p>
<p>$ projinfo -s ETRF89 -t ITRF2014 -o PROJ -q<br>
+proj=pipeline<br>
+step +proj=axisswap +order=2,1<br>
+step +proj=unitconvert +xy_in=deg +xy_out=rad<br>
+step +proj=cart +ellps=GRS80<br>
+step +inv +proj=helmert +x=0 +y=0 +z=0 +rx=0 +ry=0 +rz=0 +s=0
+dx=0 +dy=0<br>
+dz=0 +drx=0.00011 +dry=0.00057 +drz=-0.00071 +ds=0
+t_epoch=1989<br>
+convention=position_vector<br>
+step +proj=helmert +x=-0.0304 +y=-0.0355 +z=0.1308 +rx=0 +ry=0
+rz=-0.00026<br>
+s=-0.00819 +dx=-0.0001 +dy=0.0005 +dz=0.0033 +drx=0
+dry=0 +drz=-2e-05<br>
+ds=-0.00012 +t_epoch=2010 +convention=position_vector<br>
+step +inv +proj=cart +ellps=GRS80<br>
+step +proj=unitconvert +xy_in=rad +xy_out=deg<br>
+step +proj=axisswap +order=2,1<br>
<br>
</p>
<p><br>
</p>
<blockquote type="cite" cite="mid:rmir1itql7r.fsf@s1.lexort.com">
<pre class="moz-quote-pre" wrap="">
Also there's the minor issue that ETRS89 is a system not a frame and
there are many ETRFnn and ETRFnnnn frames. So ETRS89 appears to be one
of those pesky datum ensembles, from a pedantic view.
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<pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
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My software is free, but my time generally not.</pre>
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