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Hi,
<br>
<br> I've added the support of grid shift in the software suite we are developing here at YellowScan.
<br>
<br> Now that the grid shift files are found, the coordinates are projected correctly and our customer is happy.
<br>
<br> However, the projection time completly exploded: for instance, on our customer dataset, our LAS creation algorithm exports our data in approx 5s without using a grid shift, and it now takes up to 2min20s when using it.
<br>
<br> The projection pipeline used is:
<br>
<br> +proj=pipeline
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=push +v_3</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=cart +ellps=WGS84</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=helmert +x=168 +y=60 +z=-320</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +inv +proj=cart +ellps=clrk80ign</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=pop +v_3</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=lcc +lat_1=44.1 +lat_0=44.1 +lon_0=0 +k_0=0.999877499 +x_0=600000 +y_0=3200000 +ellps=clrk80ign +pm=paris</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +inv +proj=lcc +lat_1=44.1 +lat_0=44.1 +lon_0=0 +k_0=0.999877499 +x_0=600000 +y_0=3200000 +ellps=clrk80ign +pm=paris</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=hgridshift +grids=ntf_r93.gsb</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">+step +proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;"><br> </p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">The grid shift file used is ntf_r93.gsb</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;"><br> </p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px;
margin-right:0px; -qt-block-indent:0; text-indent:0px;">Is this time normal? Is there a way to speed things up? I've tried to use proj_trans_generic with no success, and exploring the source code on github, I realized that it is using a for-loop approach, using proj_trans (so no optimization to expect - but I might be wrong).</p>
<br> Any help is appreciated!
<br>
<br> Cheers !
<br>
<br>
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