<div dir="ltr"><div>Hello all,</div><div><br></div><div>I tried asking this question on SO but failed to get an answer, so here it is again:</div><div><br></div>I am trying to recreate the [EPSG example of georeferencing I=J+90 local bin grid](<a href="https://epsg.org/transformation_6918/EPSG-example-of-georeferencing-I-J-90-local-bin-grid.html">https://epsg.org/transformation_6918/EPSG-example-of-georeferencing-I-J-90-local-bin-grid.html</a>) using the `P6 I=J+90 seismic bin grid coordinate operation` (EPSG code `9666`) but the resulting CRS can't be used to transform coordinates.  <br>`xform = Transformer.from_crs('EPSG:25832', my_crs)` fails with `ProjError: Input is not a transformation.`  <br><br>Here is the `wkt` string I'm using to create the crs with `my_crs = crs.CRS.from_wkt(wkt)`.  <br><br>    DERIVEDPROJCRS["seismic survey bin grid",<br>        BASEPROJCRS["WGS 84 / UTM zone 31N",<br>            BASEGEOGCRS["WGS 84",<br>                ENSEMBLE["World Geodetic System 1984 ensemble",<br>                    MEMBER["World Geodetic System 1984 (Transit)"],<br>                    MEMBER["World Geodetic System 1984 (G730)"],<br>                    MEMBER["World Geodetic System 1984 (G873)"],<br>                    MEMBER["World Geodetic System 1984 (G1150)"],<br>                    MEMBER["World Geodetic System 1984 (G1674)"],<br>                    MEMBER["World Geodetic System 1984 (G1762)"],<br>                    MEMBER["World Geodetic System 1984 (G2139)"],<br>                    ELLIPSOID["WGS 84",6378137,298.257223563,<br>                        LENGTHUNIT["metre",1]],<br>                    ENSEMBLEACCURACY[2.0]],<br>                PRIMEM["Greenwich",0,<br>                    ANGLEUNIT["degree",0.0174532925199433]]],<br>            CONVERSION["UTM zone 31N",<br>                METHOD["Transverse Mercator",<br>                    ID["EPSG",9807]],<br>                PARAMETER["Latitude of natural origin",0,<br>                    ANGLEUNIT["degree",0.0174532925199433],<br>                    ID["EPSG",8801]],<br>                PARAMETER["Longitude of natural origin",3,<br>                    ANGLEUNIT["degree",0.0174532925199433],<br>                    ID["EPSG",8802]],<br>                PARAMETER["Scale factor at natural origin",0.9996,<br>                    SCALEUNIT["unity",1],<br>                    ID["EPSG",8805]],<br>                PARAMETER["False easting",500000,<br>                    LENGTHUNIT["metre",1],<br>                    ID["EPSG",8806]],<br>                PARAMETER["False northing",0,<br>                    LENGTHUNIT["metre",1],<br>                    ID["EPSG",8807]]]],<br>        DERIVINGCONVERSION["seismic survey bin grid",<br>            METHOD["P6 I=J+90 seismic bin grid coordinate operation",<br>                ID["EPSG",9666]],<br>            PARAMETER["Bin grid origin I",1,<br>                SCALEUNIT["Bin",1],<br>                ID["EPSG",8733]],<br>            PARAMETER["Bin grid origin J",1,<br>                SCALEUNIT["Bin",1],<br>                ID["EPSG",8734]],<br>            PARAMETER["Bin grid origin Easting",456781,<br>                LENGTHUNIT["metre",1],<br>                ID["EPSG",8735]],<br>            PARAMETER["Bin grid origin Northing",5836723,<br>                LENGTHUNIT["metre",1],<br>                ID["EPSG",8736]],<br>            PARAMETER["Scale factor of bin grid",0.99984,<br>                SCALEUNIT["Unity",1],<br>                ID["EPSG",8737]],<br>            PARAMETER["Bin width on I-axis",25,<br>                LENGTHUNIT["metre",1],<br>                ID["EPSG",8738]],<br>            PARAMETER["Bin width on J-axis",12.5,<br>                LENGTHUNIT["metre",1],<br>                ID["EPSG",8739]],<br>            PARAMETER["Map grid bearing of bin grid J-axis",20,<br>                ANGLEUNIT["degree",0.0174532925199433],<br>                ID["EPSG",8740]],<br>            PARAMETER["Bin node increment on I-axis",1,<br>                SCALEUNIT["Bin",1],<br>                ID["EPSG",8741]],<br>            PARAMETER["Bin node increment on J-axis",1,<br>                SCALEUNIT["Bin",1],<br>                ID["EPSG",8742]]],<br>        CS[ordinal,2],<br>            AXIS["inline (I)",eastSouthEast,<br>                ORDER[1],<br>                SCALEUNIT["Bin",1]],<br>            AXIS["crossline (J)",northNorthEast,<br>                ORDER[2],<br>                SCALEUNIT["Bin",1]],<br>        USAGE[<br>            SCOPE["Navigation and medium accuracy spatial referencing."],<br>            AREA["Between 0°E and 6°E, northern hemisphere between equator and 84°N, onshore and offshore. Algeria. Andorra. Belgium. Benin. Burkina Faso. Denmark - North Sea. France. Germany - North Sea. Ghana. Luxembourg. Mali. Netherlands. Niger. Nigeria. Norway. Spain. Togo. United Kingdom (UK) - North Sea."],<br>            BBOX[0,0,84,6]]]<br><br>What's wrong ?<br><div><br></div><div>Many thanks,</div><div>YeO</div></div>