<div style="font-family: arial; font-size: 14px;"><div style="font-family: arial; font-size: 14px;">Hello,<br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">I recently messaged about matching projection/transformations between GDAL/OSR and ESRI (gdal-dev Digest, <span style="box-sizing: inherit; quotes: "“" "”" "‘" "’";">Vol 213, Issue 35).  </span><br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">I had two follow-up questions regarding transforming from a geographic CRS to a projected CRS.  When transforming from EPSG:6318 to a projected CRS EPSG:32015, the point values I receive are different than in ESRI.  My first question is, when I am setting the osr.SetAxisMappingStrategy(osr.OAMS_TRADITIONAL_GIS_ORDER) parameter for EPSG:6318, why would the transformation points be different?<br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">My second question is regarding the compound transformation that ESRI applies.  In this example ArcPy uses the "WGS_1984_(ITRF00)_To_NAD_1983_2011 + NAD_1927_To_WGS_1984_3" transformation to project between EPSG:6318 and EPSG:32015.  Is there a way to replicate such a transformation using the python GDAL/OSR libraries?<br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">ESRI code:<br></div></div><pre style="background-color:#282c34;color:#abb2bf;font-family:'JetBrains Mono',monospace;font-size:9.8pt;">arc_fromsr = arcpy.<span style="color:#61afef;">SpatialReference</span><span style="color:#d19a66;">(6318)<br></span>arc_tosr = arcpy.<span style="color:#61afef;">SpatialReference</span><span style="color:#d19a66;">(32015)<br></span>arcpoint = arcpy.<span style="color:#61afef;">PointGeometry</span><span style="color:#d19a66;">(</span>arcpy.<span style="color:#61afef;">Point</span><span style="color:#d19a66;">(</span>*<span style="color:#d19a66;">test_coords)</span>, arc_fromsr<span style="color:#d19a66;">)
</span>transformers = arcpy.<span style="color:#61afef;">ListTransformations</span><span style="color:#d19a66;">(</span>arc_fromsr, arc_tosr<span style="color:#d19a66;">)
# transformers[0] is WGS_1984_(ITRF00)_To_NAD_1983_2011 + NAD_1927_To_WGS_1984_3<br></span>new_arcpoint = arcpoint.<span style="color:#61afef;">projectAs</span><span style="color:#d19a66;">(</span>arc_tosr, transformers<span style="color:#d19a66;">[0])</span></pre><div style="font-family: arial; font-size: 14px;"><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">GDAL\OSR code:<br></div></div><pre style="background-color:#282c34;color:#abb2bf;font-family:'JetBrains Mono',monospace;font-size:9.8pt;">to_nad = osr.<span style="color:#61afef;">SpatialReference</span><span style="color:#d19a66;">()<br></span>to_nad.<span style="color:#61afef;">ImportFromEPSG</span><span style="color:#d19a66;">(6318)<br></span>to_nad.<span style="color:#61afef;">SetAxisMappingStrategy</span><span style="color:#d19a66;">(</span>osr.OAMS_TRADITIONAL_GIS_ORDER<span style="color:#d19a66;">)</span><span style="color:#d19a66;"><br></span>final = osr.<span style="color:#61afef;">SpatialReference</span><span style="color:#d19a66;">()<br></span>final.<span style="color:#61afef;">ImportFromEPSG</span><span style="color:#d19a66;">(32015)</span><span style="color:#d19a66;"><br></span>outpoint = ogr.<span style="color:#61afef;">Geometry</span><span style="color:#d19a66;">(</span>ogr.wkbPoint<span style="color:#d19a66;">)<br></span>outpoint.<span style="color:#61afef;">AddPoint_2D</span><span style="color:#d19a66;">(</span>*<span style="color:#d19a66;">test_coords)<br></span>outpoint.<span style="color:#61afef;">AssignSpatialReference</span><span style="color:#d19a66;">(</span>to_nad<span style="color:#d19a66;">)<br></span>outpoint.<span style="color:#61afef;">TransformTo</span><span style="color:#d19a66;">(</span>final<span style="color:#d19a66;">)</span></pre><div style="font-family: arial; font-size: 14px;"><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;"><b>Input test coordinate: -73.964183, 40.785075</b><b><br></b></div><div style="font-family: arial; font-size: 14px;"><b>GDAL\OSR transformation output: 602119.3891505665, 286201.7616068426</b><b><br></b></div><div style="font-family: arial; font-size: 14px;"><b>ESRI\ArcPy transformation output: 602115.6116177095, 286190.512887311</b><br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">Any help is again, greatly appreciated.<br></div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;">Sincerely,<br></div><div style="font-family: arial; font-size: 14px;">Adam Gutonski</div><div style="font-family: arial; font-size: 14px;"><br></div><div style="font-family: arial; font-size: 14px;" class="protonmail_signature_block"><div class="protonmail_signature_block-user protonmail_signature_block-empty"></div><div class="protonmail_signature_block-proton">Sent with <a rel="noopener noreferrer" href="https://protonmail.com/" target="_blank">ProtonMail</a> Secure Email.</div></div><div><br></div></div><div style="font-family: arial; font-size: 14px;"><br></div>