<div dir="ltr">Hi<div><br></div><div>Is there a "more modern" way to use a geoid file that is not included in the default ones? (let's say, a non open one, like the German)<br>EXTENSION["PROJ4_GRIDS","HT2_0.gtx"] seems to be "proj4 style", right?</div><div><br></div><div>Even mentioned months ago that the tag GEOIDMODEL meaning was changed by EPSG somehow (or it was not clear at the beginning, and they implemented in a different way). But I do not know is that working in PROJ.</div><div><br></div><div>When a user has a non-free geoid file, and want to use it with PROJ, what is the proper procedure without changing "proj.db"? (I would prefer something in the CRS WKT more than transformation pipeline. But it is just a wish)</div><div><br></div><div>BTW, I do not want to use TOWGS84 (that was part of the problem above).<br></div><div><br></div><div>Thanks</div><div>Javier.</div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__<br>Entre dos pensamientos racionales <br>hay infinitos pensamientos irracionales.<br><br></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 19 Mar 2022 at 00:17, Steve Riddell <<a href="mailto:sriddell@geocue.com">sriddell@geocue.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal">Thanks very much, Even. For reporting the problem, I “packaged up” a case with CRS’s with EPGS codes. For the actual problem I’m working, the target CRS is a custom projection –no EPSG.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal"><b>From:</b> Even Rouault <<a href="mailto:even.rouault@spatialys.com" target="_blank">even.rouault@spatialys.com</a>> <br>
<b>Sent:</b> Friday, March 18, 2022 5:05 PM<br>
<b>To:</b> Steve Riddell <<a href="mailto:sriddell@geocue.com" target="_blank">sriddell@geocue.com</a>>; <a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a><br>
<b>Subject:</b> Re: OGRCreateCoordinateTransformation()<u></u><u></u></p>
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</div>
<p class="MsoNormal"><u></u> <u></u></p>
<p>Steve,<u></u><u></u></p>
<p>Fix in PROJ queued in <a href="https://github.com/OSGeo/PROJ/pull/3123" target="_blank">https://github.com/OSGeo/PROJ/pull/3123</a><u></u><u></u></p>
<p>The complexity of dealing with legacy features TOWGS84[] and PROJ4_GRIDS is highly stressing PROJ pipeline computation engine.<u></u><u></u></p>
<p>Using the plain EPSG codes EPSG:4955 -> EPSG:4617+5713 would be much preferable here<u></u><u></u></p>
<p>Even<u></u><u></u></p>
<div>
<p class="MsoNormal">Le 18/03/2022 à 21:14, Steve Riddell a écrit :<u></u><u></u></p>
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<blockquote style="margin-top:5pt;margin-bottom:5pt">
<p class="MsoNormal">Hi,<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">I’m getting an error (below) using GDAL trying to set up a transformation between NAD83(CSRS) geodetic, w/ ellipsoidal heights, and NAD83(CSRS) geodetic, CGVD28 heights. Similar transformations work fine on some datums, but fail on others.
Hope someone can offer some insight. Note the if I don't use the PROJ4_GRIDS extension, I don't get the error, but I don't get the geoid adjustment either.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">COMPD_CS["NAD83(CSRS) + Ellipsoid (Meters)",<u></u><u></u></p>
<p class="MsoNormal"> GEOGCS["NAD83(CSRS)",<u></u><u></u></p>
<p class="MsoNormal"> DATUM["NAD83_Canadian_Spatial_Reference_System",<u></u><u></u></p>
<p class="MsoNormal"> SPHEROID["GRS 1980",6378137,298.257222101,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","7019"]],<u></u><u></u></p>
<p class="MsoNormal"> TOWGS84[0,0,0,0,0,0,0],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","6140"]],<u></u><u></u></p>
<p class="MsoNormal"> PRIMEM["Greenwich",0,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","8901"]],<u></u><u></u></p>
<p class="MsoNormal"> UNIT["degree",0.0174532925199433,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9122"]],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","4617"]],<u></u><u></u></p>
<p class="MsoNormal"> VERT_CS["Ellipsoid (Meters)",<u></u><u></u></p>
<p class="MsoNormal"> VERT_DATUM["Ellipsoid",2002],<u></u><u></u></p>
<p class="MsoNormal"> UNIT["metre",1,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9001"]],<u></u><u></u></p>
<p class="MsoNormal"> AXIS["ellipsoidal height",UP]]]<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">COMPD_CS["NAD83(CSRS) + CGVD28 height - HT2_0",<u></u><u></u></p>
<p class="MsoNormal"> GEOGCS["NAD83(CSRS)",<u></u><u></u></p>
<p class="MsoNormal"> DATUM["NAD83_Canadian_Spatial_Reference_System",<u></u><u></u></p>
<p class="MsoNormal"> SPHEROID["GRS 1980",6378137,298.257222101,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","7019"]],<u></u><u></u></p>
<p class="MsoNormal"> TOWGS84[0,0,0,0,0,0,0],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","6140"]],<u></u><u></u></p>
<p class="MsoNormal"> PRIMEM["Greenwich",0,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","8901"]],<u></u><u></u></p>
<p class="MsoNormal"> UNIT["degree",0.0174532925199433,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9122"]],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","4617"]],<u></u><u></u></p>
<p class="MsoNormal"> VERT_CS["CGVD28 height - HT2_0",<u></u><u></u></p>
<p class="MsoNormal"> VERT_DATUM["Canadian Geodetic Vertical Datum of 1928",2005,<u></u><u></u></p>
<p class="MsoNormal"> EXTENSION["PROJ4_GRIDS","HT2_0.gtx"],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","5114"]],<u></u><u></u></p>
<p class="MsoNormal"> UNIT["metre",1,<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9001"]],<u></u><u></u></p>
<p class="MsoNormal"> AXIS["Gravity-related height",UP],<u></u><u></u></p>
<p class="MsoNormal"> AUTHORITY["EPSG","5713"]]]<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">ERROR 6: Cannot find coordinate operations from `EPSG:4955' to `COMPOUNDCRS["NAD83(CSRS) + CGVD28 height - HT2_0",BOUNDCRS[SOURCECRS[GEOGCRS["NAD83(CSRS)",DATUM["NAD83 Canadian Spatial Reference System",ELLIPSOID["GRS 1980",6378137,298.257222101,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic
latitude (Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic longitude (Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4617]]],TARGETCRS[GEOGCRS["WGS 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["latitude",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["longitude",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]]],ABRIDGEDTRANSFORMATION["Transformation
from NAD83(CSRS) to WGS84",METHOD["Position Vector transformation (geog2D domain)",ID["EPSG",9606]],PARAMETER["X-axis translation",0,ID["EPSG",8605]],PARAMETER["Y-axis translation",0,ID["EPSG",8606]],PARAMETER["Z-axis translation",0,ID["EPSG",8607]],PARAMETER["X-axis
rotation",0,ID["EPSG",8608]],PARAMETER["Y-axis rotation",0,ID["EPSG",8609]],PARAMETER["Z-axis rotation",0,ID["EPSG",8610]],PARAMETER["Scale difference",1,ID["EPSG",8611]]]],BOUNDCRS[SOURCECRS[VERTCRS["CGVD28 height - HT2_0",VDATUM["Canadian Geodetic Vertical
Datum of 1928"],CS[vertical,1],AXIS["gravity-related height",up,LENGTHUNIT["metre",1]],ID["EPSG",5713]]],TARGETCRS[GEOGCRS["WGS 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,3],AXIS["latitude",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["longitude",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],AXIS["ellipsoidal
height",up,ORDER[3],LENGTHUNIT["metre",1]],ID["EPSG",4979]]],ABRIDGEDTRANSFORMATION["CGVD28 height - HT2_0 to WGS84 ellipsoidal height",METHOD["GravityRelatedHeight to Geographic3D"],PARAMETERFILE["Geoid (height correction) model file","HT2_0.gtx",ID["EPSG",8666]]]]]'<u></u><u></u></p>
<pre> <u></u><u></u></pre>
<pre><span style="font-family:Calibri,sans-serif">Thanks in advance for any assistance!<u></u><u></u></span></pre>
<pre><span style="font-family:Calibri,sans-serif">Best regards,</span><u></u><u></u></pre>
<pre><span style="font-family:Calibri,sans-serif">Steve</span><u></u><u></u></pre>
<pre><span style="font-family:Calibri,sans-serif"> </span><u></u><u></u></pre>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:13.5pt;font-family:Tahoma,sans-serif">Steve Riddell</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-family:Tahoma,sans-serif">Software Engineering</span><u></u><u></u></p>
<p class="MsoNormal"><b><span style="color:rgb(82,82,82)">GeoCue Group, Inc.</span></b><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt">520 6th Street | Madison, AL 35756 USA</span><u></u><u></u></p>
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<b>Fax:</b> 256.461.8249 </span><u></u><u></u></p>
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<a href="https://support.geocue.com/" target="_blank">support.geocue.com</a> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span><u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<pre><span style="font-size:11pt;font-family:Calibri,sans-serif"> </span><u></u><u></u></pre>
</blockquote>
<pre>-- <u></u><u></u></pre>
<pre><a href="http://www.spatialys.com" target="_blank">http://www.spatialys.com</a><u></u><u></u></pre>
<pre>My software is free, but my time generally not.<u></u><u></u></pre>
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