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Geodetic CRS: TM75
Datum: Geodetic Datum of 1965
Ellipsoid: Airy Modified 1849
Prime meridian: Greenwich
Data source: EPSG
Information source: ESRI Ireland.
Revision date: 2023-01-17
Scope: Emulation of polynomial.
Remarks: Approximate alternative to official OS polynomial method (tfm code 1041). May be taken as approximate transformation TM75 to WGS 84 - see code 6947.
Method: NTv2
Area of use: Ireland - onshore. United Kingdom (UK) - Northern Ireland (Ulster) - onshore.
Description: (0,)
Definition: OGC Well Known Text 2 (2019)
COORDINATEOPERATION["TM75 to ETRS89 (3)", VERSION["OSI-Ire NT approximation"], SOURCECRS[ GEOGCRS["TM75", DATUM["Geodetic Datum of 1965", ELLIPSOID["Airy Modified 1849",6377340.189,299.3249646, 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",4300]]], TARGETCRS[ GEOGCRS["ETRS89", ENSEMBLE["European Terrestrial Reference System 1989 ensemble", MEMBER["European Terrestrial Reference Frame 1989"], MEMBER["European Terrestrial Reference Frame 1990"], MEMBER["European Terrestrial Reference Frame 1991"], MEMBER["European Terrestrial Reference Frame 1992"], MEMBER["European Terrestrial Reference Frame 1993"], MEMBER["European Terrestrial Reference Frame 1994"], MEMBER["European Terrestrial Reference Frame 1996"], MEMBER["European Terrestrial Reference Frame 1997"], MEMBER["European Terrestrial Reference Frame 2000"], MEMBER["European Terrestrial Reference Frame 2005"], MEMBER["European Terrestrial Reference Frame 2014"], MEMBER["European Terrestrial Reference Frame 2020"], MEMBER["ETRS89-DNK"], MEMBER["Estonia 1997"], MEMBER["Albanian Geodetic Reference Frame 2010"], MEMBER["ETRS89-ALB [CORS]"], MEMBER["ETRS89-AUT [2002]"], MEMBER["Belgian Reference Frame 2002"], MEMBER["Belgian Reference Frame 2011"], MEMBER["BH_ETRS89"], MEMBER["Bulgaria Geodetic System 2005"], MEMBER["Croatian Terrestrial Reference System 1996"], MEMBER["AGRS2010 (ETRF2000)"], MEMBER["CROPOS"], MEMBER["ETRF2000 Poland"], MEMBER["ETRS89/DREF91 Realization 2016"], MEMBER["ETRS89/DREF91 Realization 2025"], MEMBER["ETRS89-CZE [2007]"], MEMBER["ETRS89-ESP [REGENTE]"], MEMBER["ETRS89-ESP [ERGNSS]"], MEMBER["ETRS89-FRO [2008]"], MEMBER["ETRS89-GRC [HTRS07]"], MEMBER["ETRS89-HUN [ETRF2000]"], MEMBER["ETRS89-IRE [ETRF2000]"], MEMBER["ETRS89-MKD [EUREF-MAK2010]"], MEMBER["ETRS89-NOR [EUREF89]"], MEMBER["ETRS89-PRT [1995]"], MEMBER["ETRS89-ROU [ETRF2000]"], MEMBER["ETRS89-SVK [SKTRF09]"], MEMBER["ETRS89-SVK [SKTRF2022]"], MEMBER["EUREF-FIN"], MEMBER["Istituto Geografico Militaire 1995"], MEMBER["Kosovo Reference System 2001"], MEMBER["Latvian geodetic coordinate system 1992"], MEMBER["Latvian coordinate system 2020"], MEMBER["Lithuania 1994 (ETRS89)"], MEMBER["MOLDREF99"], MEMBER["OSNet v2009"], MEMBER["Reseau Geodesique Francais 1993 v1"], MEMBER["Reseau Geodesique Francais 1993 v2"], MEMBER["Reseau Geodesique Francais 1993 v2b"], MEMBER["Rete Dinamica Nazionale 2008"], MEMBER["Serbian Reference Network 1998"], MEMBER["Serbian Spatial Reference System 2000"], MEMBER["Slovenia Geodetic Datum 1996"], MEMBER["SWEREF 99"], MEMBER["Swiss Terrestrial Reference Frame 1995"], ELLIPSOID["GRS 1980",6378137,298.257222101, LENGTHUNIT["metre",1]], ENSEMBLEACCURACY[0.1]], 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",4258]]], METHOD["NTv2", ID["EPSG",9615]], PARAMETERFILE["Latitude and longitude difference file","tm75_etrs89.gsb"], OPERATIONACCURACY[0.41], USAGE[ SCOPE["Emulation of polynomial."], AREA["Ireland - onshore. United Kingdom (UK) - Northern Ireland (Ulster) - onshore."], BBOX[51.39,-10.56,55.43,-5.34]], ID["EPSG",6946], REMARK["Approximate alternative to official OS polynomial method (tfm code 1041). May be taken as approximate transformation TM75 to WGS 84 - see code 6947."]]
Definition: JavaScript (Proj4js)
proj4.defs("EPSG:6946","+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=tm75_etrs89.gsb +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1");
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "Transformation", "name": "TM75 to ETRS89 (3)", "source_crs": { "type": "GeographicCRS", "name": "TM75", "datum": { "type": "GeodeticReferenceFrame", "name": "Geodetic Datum of 1965", "ellipsoid": { "name": "Airy Modified 1849", "semi_major_axis": 6377340.189, "inverse_flattening": 299.3249646 } }, "coordinate_system": { "subtype": "ellipsoidal", "axis": [ { "name": "Geodetic latitude", "abbreviation": "Lat", "direction": "north", "unit": "degree" }, { "name": "Geodetic longitude", "abbreviation": "Lon", "direction": "east", "unit": "degree" } ] }, "id": { "authority": "EPSG", "code": 4300 }, "remarks": "Uses Geodetic Datum of 1965 which should not be confused with the 1965 adjustment (TM65, datum code 6299 and CRS code 4299). Replaces OSNI52 (CRS code 4188) and TM65 (CRS code 4299). Replaced by IRENET95 (CRS code 4173)." }, "target_crs": { "type": "GeographicCRS", "name": "ETRS89", "datum_ensemble": { "name": "European Terrestrial Reference System 1989 ensemble", "members": [ { "name": "European Terrestrial Reference Frame 1989", "id": { "authority": "EPSG", "code": 1178 } }, { "name": "European Terrestrial Reference Frame 1990", "id": { "authority": "EPSG", "code": 1179 } }, { "name": "European Terrestrial Reference Frame 1991", "id": { "authority": "EPSG", "code": 1180 } }, { "name": "European Terrestrial Reference Frame 1992", "id": { "authority": "EPSG", "code": 1181 } }, { "name": "European Terrestrial Reference Frame 1993", "id": { "authority": "EPSG", "code": 1182 } }, { "name": "European Terrestrial Reference Frame 1994", "id": { "authority": "EPSG", "code": 1183 } }, { "name": "European Terrestrial Reference Frame 1996", "id": { "authority": "EPSG", "code": 1184 } }, { "name": "European Terrestrial Reference Frame 1997", "id": { "authority": "EPSG", "code": 1185 } }, { "name": "European Terrestrial Reference Frame 2000", "id": { "authority": "EPSG", "code": 1186 } }, { "name": "European Terrestrial Reference Frame 2005", "id": { "authority": "EPSG", "code": 1204 } }, { "name": "European Terrestrial Reference Frame 2014", "id": { "authority": "EPSG", "code": 1206 } }, { "name": "European Terrestrial Reference Frame 2020", "id": { "authority": "EPSG", "code": 1382 } }, { "name": "ETRS89-DNK", "id": { "authority": "EPSG", "code": 1412 } }, { "name": "Estonia 1997", "id": { "authority": "EPSG", "code": 6180 } }, { "name": "Albanian Geodetic Reference Frame 2010", "id": { "authority": "EPSG", "code": 1429 } }, { "name": "ETRS89-ALB [CORS]", "id": { "authority": "EPSG", "code": 1430 } }, { "name": "ETRS89-AUT [2002]", "id": { "authority": "EPSG", "code": 1431 } }, { "name": "Belgian Reference Frame 2002", "id": { "authority": "EPSG", "code": 1432 } }, { "name": "Belgian Reference Frame 2011", "id": { "authority": "EPSG", "code": 1447 } }, { "name": "BH_ETRS89", "id": { "authority": "EPSG", "code": 1358 } }, { "name": "Bulgaria Geodetic System 2005", "id": { "authority": "EPSG", "code": 1167 } }, { "name": "Croatian Terrestrial Reference System 1996", "id": { "authority": "EPSG", "code": 6761 } }, { "name": "AGRS2010 (ETRF2000)", "id": { "authority": "EPSG", "code": 1427 } }, { "name": "CROPOS", "id": { "authority": "EPSG", "code": 1445 } }, { "name": "ETRF2000 Poland", "id": { "authority": "EPSG", "code": 1305 } }, { "name": "ETRS89/DREF91 Realization 2016", "id": { "authority": "EPSG", "code": 1353 } }, { "name": "ETRS89/DREF91 Realization 2025", "id": { "authority": "EPSG", "code": 1446 } }, { "name": "ETRS89-CZE [2007]", "id": { "authority": "EPSG", "code": 1433 } }, { "name": "ETRS89-ESP [REGENTE]", "id": { "authority": "EPSG", "code": 1441 } }, { "name": "ETRS89-ESP [ERGNSS]", "id": { "authority": "EPSG", "code": 1442 } }, { "name": "ETRS89-FRO [2008]", "id": { "authority": "EPSG", "code": 1436 } }, { "name": "ETRS89-GRC [HTRS07]", "id": { "authority": "EPSG", "code": 1437 } }, { "name": "ETRS89-HUN [ETRF2000]", "id": { "authority": "EPSG", "code": 1444 } }, { "name": "ETRS89-IRE [ETRF2000]", "id": { "authority": "EPSG", "code": 6173 } }, { "name": "ETRS89-MKD [EUREF-MAK2010]", "id": { "authority": "EPSG", "code": 1438 } }, { "name": "ETRS89-NOR [EUREF89]", "id": { "authority": "EPSG", "code": 1407 } }, { "name": "ETRS89-PRT [1995]", "id": { "authority": "EPSG", "code": 1439 } }, { "name": "ETRS89-ROU [ETRF2000]", "id": { "authority": "EPSG", "code": 1440 } }, { "name": "ETRS89-SVK [SKTRF09]", "id": { "authority": "EPSG", "code": 1434 } }, { "name": "ETRS89-SVK [SKTRF2022]", "id": { "authority": "EPSG", "code": 1435 } }, { "name": "EUREF-FIN", "id": { "authority": "EPSG", "code": 1391 } }, { "name": "Istituto Geografico Militaire 1995", "id": { "authority": "EPSG", "code": 6670 } }, { "name": "Kosovo Reference System 2001", "id": { "authority": "EPSG", "code": 1251 } }, { "name": "Latvian geodetic coordinate system 1992", "id": { "authority": "EPSG", "code": 6661 } }, { "name": "Latvian coordinate system 2020", "id": { "authority": "EPSG", "code": 1356 } }, { "name": "Lithuania 1994 (ETRS89)", "id": { "authority": "EPSG", "code": 6126 } }, { "name": "MOLDREF99", "id": { "authority": "EPSG", "code": 1032 } }, { "name": "OSNet v2009", "id": { "authority": "EPSG", "code": 1425 } }, { "name": "Reseau Geodesique Francais 1993 v1", "id": { "authority": "EPSG", "code": 6171 } }, { "name": "Reseau Geodesique Francais 1993 v2", "id": { "authority": "EPSG", "code": 1312 } }, { "name": "Reseau Geodesique Francais 1993 v2b", "id": { "authority": "EPSG", "code": 1313 } }, { "name": "Rete Dinamica Nazionale 2008", "id": { "authority": "EPSG", "code": 1132 } }, { "name": "Serbian Reference Network 1998", "id": { "authority": "EPSG", "code": 1034 } }, { "name": "Serbian Spatial Reference System 2000", "id": { "authority": "EPSG", "code": 1214 } }, { "name": "Slovenia Geodetic Datum 1996", "id": { "authority": "EPSG", "code": 6765 } }, { "name": "SWEREF 99", "id": { "authority": "EPSG", "code": 6619 } }, { "name": "Swiss Terrestrial Reference Frame 1995", "id": { "authority": "EPSG", "code": 1449 } } ], "ellipsoid": { "name": "GRS 1980", "semi_major_axis": 6378137, "inverse_flattening": 298.257222101 }, "accuracy": "0.1", "id": { "authority": "EPSG", "code": 6258 } }, "coordinate_system": { "subtype": "ellipsoidal", "axis": [ { "name": "Geodetic latitude", "abbreviation": "Lat", "direction": "north", "unit": "degree" }, { "name": "Geodetic longitude", "abbreviation": "Lon", "direction": "east", "unit": "degree" } ] }, "id": { "authority": "EPSG", "code": 4258 }, "remarks": "Has been realized through ETRF89, ETRF90, ETRF91, ETRF92, ETRF93, ETRF94, ETRF96, ETRF97, ETRF2000, ETRF2005 and ETRF2014. This 'ensemble' covers any or all of these realizations without distinction." }, "method": { "name": "NTv2", "id": { "authority": "EPSG", "code": 9615 } }, "parameters": [ { "name": "Latitude and longitude difference file", "value": "tm75_etrs89.gsb", "id": { "authority": "EPSG", "code": 8656 } } ], "accuracy": "0.41", "scope": "Emulation of polynomial.", "area": "Ireland - onshore. United Kingdom (UK) - Northern Ireland (Ulster) - onshore.", "bbox": { "south_latitude": 51.39, "west_longitude": -10.56, "north_latitude": 55.43, "east_longitude": -5.34 }, "id": { "authority": "EPSG", "code": 6946 }, "remarks": "Approximate alternative to official OS polynomial method (tfm code 1041). May be taken as approximate transformation TM75 to WGS 84 - see code 6947." }
Definition: MapServer - MAPfile
PROJECTION "proj=pipeline" "step" "proj=axisswap" "order=2,1" "step" "proj=unitconvert" "xy_in=deg" "xy_out=rad" "step" "proj=hgridshift" "grids=tm75_etrs89.gsb" "step" "proj=unitconvert" "xy_in=rad" "xy_out=deg" "step" "proj=axisswap" "order=2,1" END
Definition: Mapnik
<?xml version="1.0" encoding="utf-8"?> <Map srs="+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=tm75_etrs89.gsb +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1"> <Layer srs="+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=tm75_etrs89.gsb +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1"> </Layer> </Map>
Definition: SQL (PostGIS)
INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 6946, 'EPSG', 6946, '+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=tm75_etrs89.gsb +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1', 'None');
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