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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">COMPD_CS["NAD83(CSRS) + Ellipsoid (Meters)",<o:p></o:p></p>
<p class="MsoNormal"> GEOGCS["NAD83(CSRS)",<o:p></o:p></p>
<p class="MsoNormal"> DATUM["NAD83_Canadian_Spatial_Reference_System",<o:p></o:p></p>
<p class="MsoNormal"> SPHEROID["GRS 1980",6378137,298.257222101,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","7019"]],<o:p></o:p></p>
<p class="MsoNormal"> TOWGS84[0,0,0,0,0,0,0],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","6140"]],<o:p></o:p></p>
<p class="MsoNormal"> PRIMEM["Greenwich",0,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","8901"]],<o:p></o:p></p>
<p class="MsoNormal"> UNIT["degree",0.0174532925199433,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9122"]],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","4617"]],<o:p></o:p></p>
<p class="MsoNormal"> VERT_CS["Ellipsoid (Meters)",<o:p></o:p></p>
<p class="MsoNormal"> VERT_DATUM["Ellipsoid",2002],<o:p></o:p></p>
<p class="MsoNormal"> UNIT["metre",1,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9001"]],<o:p></o:p></p>
<p class="MsoNormal"> AXIS["ellipsoidal height",UP]]]<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">COMPD_CS["NAD83(CSRS) + CGVD28 height - HT2_0",<o:p></o:p></p>
<p class="MsoNormal"> GEOGCS["NAD83(CSRS)",<o:p></o:p></p>
<p class="MsoNormal"> DATUM["NAD83_Canadian_Spatial_Reference_System",<o:p></o:p></p>
<p class="MsoNormal"> SPHEROID["GRS 1980",6378137,298.257222101,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","7019"]],<o:p></o:p></p>
<p class="MsoNormal"> TOWGS84[0,0,0,0,0,0,0],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","6140"]],<o:p></o:p></p>
<p class="MsoNormal"> PRIMEM["Greenwich",0,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","8901"]],<o:p></o:p></p>
<p class="MsoNormal"> UNIT["degree",0.0174532925199433,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9122"]],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","4617"]],<o:p></o:p></p>
<p class="MsoNormal"> VERT_CS["CGVD28 height - HT2_0",<o:p></o:p></p>
<p class="MsoNormal"> VERT_DATUM["Canadian Geodetic Vertical Datum of 1928",2005,<o:p></o:p></p>
<p class="MsoNormal"> EXTENSION["PROJ4_GRIDS","HT2_0.gtx"],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","5114"]],<o:p></o:p></p>
<p class="MsoNormal"> UNIT["metre",1,<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","9001"]],<o:p></o:p></p>
<p class="MsoNormal"> AXIS["Gravity-related height",UP],<o:p></o:p></p>
<p class="MsoNormal"> AUTHORITY["EPSG","5713"]]]<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></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]]]]]'<o:p></o:p></p>
<pre><o:p> </o:p></pre>
<pre><span style="font-family:"Calibri",sans-serif">Thanks in advance for any assistance!<br>Best regards,<o:p></o:p></span></pre>
<pre><span style="font-family:"Calibri",sans-serif">Steve<o:p></o:p></span></pre>
<pre><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></pre>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:13.5pt;font-family:"Tahoma",sans-serif">Steve Riddell<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif">Software Engineering</span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="color:#525252">GeoCue Group, Inc.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:10.0pt">520 6th Street | Madison, AL 35756 USA</span><b><span style="color:#525252"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt">Phone:</span></b><span style="font-size:10.0pt"> 256.461.8289 |
<b>Fax:</b> 256.461.8249 <o:p></o:p></span></p>
<p class="MsoNormal"><i><span style="color:#0070C0">LIDAR/Drone Mapping Software & Services
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<p class="MsoNormal"><span style="font-size:10.0pt"> </span><a href="http://www.geocue.com/"><span style="font-size:10.0pt;color:#0070C0">www.geocue.com</span></a><span style="font-size:10.0pt;color:#0070C0">
<a href="https://support.geocue.com/">support.geocue.com</a> </span><span style="font-size:10.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></pre>
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