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<p><span lang="EN-GB">> Are we completely sure that nobody no longer use nl_nsgi_naptrans2018.tif ?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">No, but I think there has never been a reason to use nl_nsgi_naptrans2018.tif. The only difference between nl_nsgi_naptrans2018.tif
and nl_nsgi_nlgeo2018.tif is the interpolation CRS. In theory somebody could use nl_nsgi_naptrans2018.tif in a PROJ pipeline, e.g.:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">cct +proj=pipeline <o:p>
</o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=hgridshift +inv +grids=nl_nsgi_rdtrans2018.tif
<o:p></o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=vgridshift +grids=<b>nl_nsgi_naptrans2018.tif
<o:p></o:p></b></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=sterea +lat_0=52.156160556 +lon_0=5.387638889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">However, we never published such a PROJ pipeline, since the need for a interpolation CRS other than ETRS89 could always be avoided in
a pipeline, e.g.:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">cct +proj=pipeline <o:p>
</o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=vgridshift +grids=<b>nl_nsgi_nlgeo2018.tif
<o:p></o:p></b></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=hgridshift +inv +grids=nl_nsgi_rdtrans2018.tif
<o:p></o:p></span></p>
<p class="Default"><span lang="EN-GB" style="font-size:9.0pt">+step +proj=sterea +lat_0=52.156160556 +lon_0=5.387638889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">The only reason we created nl_nsgi_naptrans2018.gtx is that PROJ4-style strings in older PROJ versions (that did not yet support GeoTIFF)
needed it:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:9.0pt;font-family:Consolas;color:black">+proj=sterea +lat_0=52.156160556 +lon_0=5.387638889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +nadgrids=nl_nsgi_rdtrans2018.gsb +wktext +geoidgrids=<b>nl_nsgi_naptrans2018.gtx</b>
+no_defs<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">With PROJ 6 and newer this grid is no longer needed for PROJ4-style strings either:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:9.0pt;font-family:Consolas;color:black">+proj=sterea +lat_0=52.156160556 +lon_0=5.387638889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +nadgrids=nl_nsgi_rdtrans2018.tif +geoidgrids=<b>nl_nsgi_nlgeo2018.tif</b>
+geoid_crs=WGS84 +type=crs<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:9.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">So the conversion from VDatum (.gtx) to GeoTIFF (.tif) was never needed for nl_nsgi_naptrans2018.gtx, but should we keep it now is there?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Jochem<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:9.0pt"><o:p> </o:p></span></p>
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