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Name: OSGB36 to WGS 84 (9)
Method: NTv2
Grid Files: OSTN15_NTv2_OSGBtoETRS.gsb
Remarks: Parameter values taken from OSGB36 to ETRS89 (2) (tfm code 7709) assuming that ETRS89 is coincident with WGS 84 within the accuracy of the tfm. Replaces OSGB36 to WGS 84 (7) (tfm code 5339).
Information source: EPSG
Revision date: 2021-08-19
Unit: metre
Geodetic CRS: OSGB36
Datum: Ordnance Survey of Great Britain 1936
Ellipsoid: Airy 1830
Prime meridian: Greenwich
Data source: EPSG
Information source: Ordnance Survey of Great Britain on behalf of ESRI (UK).
Revision date: 2026-03-05
Scope: GIS.
Remarks: Heathrow Airport GIS Grid 2026 approximates Heathrow Airport Grid (HAG) (CRS code 11378) to an accuracy of better than 12mm within airport area and 89 mm across full area of use (2D RMS 0.007 and 0.039 m respectively derived through comparison of coordinates at 100m spacing throughout the airport area). Created for use in GIS applications that do not support the true HAG definition through engineering CRS (code 11378) and similarity transformation to British National Grid (code 11388). Accuracy of approximation deteriorates beyond airport extent - do not use this CRS beyond that area.
Area of use: UK - Heathrow airport and surrounding area.
Coordinate system: Cartesian 2D CS. Axes: easting, northing (E,N). Orientations: east, north. UoM: m.
&stroke=red&width=2&path=49.75,-9.01|61.01,-9.01|61.01,2.01|49.75,2.01|49.75,-9.01)
Center coordinates
-183404.94 445426.84
Projected bounds:
-572161.43 -185809.87
147733.6 977320.71
WGS84 bounds:
-9.01 49.75
2.01 61.01
Definition: OGC Well Known Text
PROJCS["OSGB36 / Heathrow Airport GIS Grid 2026", GEOGCS["OSGB36", DATUM["Ordnance_Survey_of_Great_Britain_1936", SPHEROID["Airy 1830",6377563.396,299.3249646], EXTENSION["PROJ4_GRIDS","uk_os_OSTN15_NTv2_OSGBtoETRS.tif"]], PRIMEM["Greenwich",0, AUTHORITY["EPSG","8901"]], UNIT["degree",0.0174532925199433, AUTHORITY["EPSG","9122"]], AUTHORITY["EPSG","4277"]], PROJECTION["Local Orthographic"], PARAMETER["latitude_of_center",51.4701102238889], PARAMETER["longitude_of_center",-0.451656585555556], PARAMETER["azimuth",359.700932272222], PARAMETER["scale_factor",1.000002816], PARAMETER["false_easting",7334.818], PARAMETER["false_northing",5637.421], UNIT["metre",1, AUTHORITY["EPSG","9001"]], AXIS["Easting",EAST], AXIS["Northing",NORTH], AUTHORITY["EPSG","11390"]]
Definition: OGC Well Known Text 2 (2019)
BOUNDCRS[ SOURCECRS[ PROJCRS["OSGB36 / Heathrow Airport GIS Grid 2026", BASEGEOGCRS["OSGB36", DATUM["Ordnance Survey of Great Britain 1936", ELLIPSOID["Airy 1830",6377563.396,299.3249646, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4277]], CONVERSION["Heathrow Airport GIS Grid 2026", METHOD["Local Orthographic", ID["EPSG",1130]], PARAMETER["Latitude of projection centre",51.4701102238889, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8811]], PARAMETER["Longitude of projection centre",-0.451656585555556, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8812]], PARAMETER["Azimuth at projection centre",359.700932272222, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8813]], PARAMETER["Scale factor at projection centre",1.000002816, SCALEUNIT["unity",1], ID["EPSG",8815]], PARAMETER["Easting at projection centre",7334.818, LENGTHUNIT["metre",1], ID["EPSG",8816]], PARAMETER["Northing at projection centre",5637.421, LENGTHUNIT["metre",1], ID["EPSG",8817]]], CS[Cartesian,2], AXIS["(E)",east, ORDER[1], LENGTHUNIT["metre",1]], AXIS["(N)",north, ORDER[2], LENGTHUNIT["metre",1]], USAGE[ SCOPE["GIS."], AREA["UK - Heathrow airport and surrounding area."], BBOX[51.42,-0.56,51.52,-0.37]], ID["EPSG",11390]]], TARGETCRS[ GEOGCRS["WGS 84", ENSEMBLE["World Geodetic System 1984 ensemble", MEMBER["World Geodetic System 1984 (Transit)"], MEMBER["World Geodetic System 1984 (G730)"], MEMBER["World Geodetic System 1984 (G873)"], MEMBER["World Geodetic System 1984 (G1150)"], MEMBER["World Geodetic System 1984 (G1674)"], MEMBER["World Geodetic System 1984 (G1762)"], MEMBER["World Geodetic System 1984 (G2139)"], MEMBER["World Geodetic System 1984 (G2296)"], ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1]], ENSEMBLEACCURACY[2.0]], 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]], USAGE[ SCOPE["Horizontal component of 3D system."], AREA["World."], BBOX[-90,-180,90,180]], ID["EPSG",4326]]], ABRIDGEDTRANSFORMATION["OSGB36 to WGS 84 (9)", METHOD["NTv2", ID["EPSG",9615]], PARAMETERFILE["Latitude and longitude difference file","OSTN15_NTv2_OSGBtoETRS.gsb"], USAGE[ SCOPE["(null/copy) Approximation for medium and low accuracy applications assuming equality between plate-fixed static and earth-fixed dynamic CRSs, ignoring static/dynamic CRS differences."], AREA["United Kingdom (UK) - offshore to boundary of UKCS within 49°45'N to 61°N and 9°W to 2°E; onshore Great Britain (England, Wales and Scotland). Isle of Man onshore."], BBOX[49.75,-9.01,61.01,2.01]], ID["EPSG",7710], REMARK["Parameter values taken from OSGB36 to ETRS89 (2) (tfm code 7709) assuming that ETRS89 is coincident with WGS 84 within the accuracy of the tfm. Replaces OSGB36 to WGS 84 (7) (tfm code 5339)."]]]
Definition: ESRI Well Known Text
PROJCS["OSGB36_Heathrow_Airport_GIS_Grid_2026", GEOGCS["GCS_OSGB_1936", DATUM["D_OSGB_1936", SPHEROID["Airy_1830",6377563.396,299.3249646], EXTENSION["PROJ4_GRIDS","uk_os_OSTN15_NTv2_OSGBtoETRS.tif"]], PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]], PROJECTION["Local"], PARAMETER["False_Easting",7334.818], PARAMETER["False_Northing",5637.421], PARAMETER["Scale_Factor",1.000002816], PARAMETER["Azimuth",-0.299067727777981], PARAMETER["Longitude_Of_Center",-0.451656585555556], PARAMETER["Latitude_Of_Center",51.4701102238889], UNIT["Meter",1.0]]
Definition: JavaScript (Proj4js)
proj4.defs("EPSG:11390","+proj=ortho +lat_0=51.4701102238889 +lon_0=-0.451656585555556 +alpha=359.700932272222 +k=1.000002816 +x_0=7334.818 +y_0=5637.421 +ellps=airy +nadgrids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif +units=m +no_defs +type=crs");
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "BoundCRS", "source_crs": { "type": "ProjectedCRS", "name": "OSGB36 / Heathrow Airport GIS Grid 2026", "base_crs": { "type": "GeographicCRS", "name": "OSGB36", "datum": { "type": "GeodeticReferenceFrame", "name": "Ordnance Survey of Great Britain 1936", "ellipsoid": { "name": "Airy 1830", "semi_major_axis": 6377563.396, "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": 4277 } }, "conversion": { "name": "Heathrow Airport GIS Grid 2026", "method": { "name": "Local Orthographic", "id": { "authority": "EPSG", "code": 1130 } }, "parameters": [ { "name": "Latitude of projection centre", "value": 51.4701102238889, "unit": "degree", "id": { "authority": "EPSG", "code": 8811 } }, { "name": "Longitude of projection centre", "value": -0.451656585555556, "unit": "degree", "id": { "authority": "EPSG", "code": 8812 } }, { "name": "Azimuth at projection centre", "value": 359.700932272222, "unit": "degree", "id": { "authority": "EPSG", "code": 8813 } }, { "name": "Scale factor at projection centre", "value": 1.000002816, "unit": "unity", "id": { "authority": "EPSG", "code": 8815 } }, { "name": "Easting at projection centre", "value": 7334.818, "unit": "metre", "id": { "authority": "EPSG", "code": 8816 } }, { "name": "Northing at projection centre", "value": 5637.421, "unit": "metre", "id": { "authority": "EPSG", "code": 8817 } } ] }, "coordinate_system": { "subtype": "Cartesian", "axis": [ { "name": "Easting", "abbreviation": "E", "direction": "east", "unit": "metre" }, { "name": "Northing", "abbreviation": "N", "direction": "north", "unit": "metre" } ] }, "id": { "authority": "EPSG", "code": 11390 } }, "target_crs": { "type": "GeographicCRS", "name": "WGS 84", "datum_ensemble": { "name": "World Geodetic System 1984 ensemble", "members": [ { "name": "World Geodetic System 1984 (Transit)", "id": { "authority": "EPSG", "code": 1166 } }, { "name": "World Geodetic System 1984 (G730)", "id": { "authority": "EPSG", "code": 1152 } }, { "name": "World Geodetic System 1984 (G873)", "id": { "authority": "EPSG", "code": 1153 } }, { "name": "World Geodetic System 1984 (G1150)", "id": { "authority": "EPSG", "code": 1154 } }, { "name": "World Geodetic System 1984 (G1674)", "id": { "authority": "EPSG", "code": 1155 } }, { "name": "World Geodetic System 1984 (G1762)", "id": { "authority": "EPSG", "code": 1156 } }, { "name": "World Geodetic System 1984 (G2139)", "id": { "authority": "EPSG", "code": 1309 } }, { "name": "World Geodetic System 1984 (G2296)", "id": { "authority": "EPSG", "code": 1383 } } ], "ellipsoid": { "name": "WGS 84", "semi_major_axis": 6378137, "inverse_flattening": 298.257223563 }, "accuracy": "2.0", "id": { "authority": "EPSG", "code": 6326 } }, "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": 4326 } }, "transformation": { "name": "OSGB36 to WGS 84 (9)", "method": { "name": "NTv2", "id": { "authority": "EPSG", "code": 9615 } }, "parameters": [ { "name": "Latitude and longitude difference file", "value": "OSTN15_NTv2_OSGBtoETRS.gsb", "id": { "authority": "EPSG", "code": 8656 } } ], "id": { "authority": "EPSG", "code": 7710 } } }
Definition: GeoServer
11390=PROJCS["OSGB36 / Heathrow Airport GIS Grid 2026",GEOGCS["OSGB36",DATUM["Ordnance_Survey_of_Great_Britain_1936",SPHEROID["Airy 1830",6377563.396,299.3249646],EXTENSION["PROJ4_GRIDS","uk_os_OSTN15_NTv2_OSGBtoETRS.tif"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4277"]],PROJECTION["Local Orthographic"],PARAMETER["latitude_of_center",51.4701102238889],PARAMETER["longitude_of_center",-0.451656585555556],PARAMETER["azimuth",359.700932272222],PARAMETER["scale_factor",1.000002816],PARAMETER["false_easting",7334.818],PARAMETER["false_northing",5637.421],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","11390"]]
Definition: MapServer - MAPfile
PROJECTION "proj=ortho" "lat_0=51.4701102238889" "lon_0=-0.451656585555556" "alpha=359.700932272222" "k=1.000002816" "x_0=7334.818" "y_0=5637.421" "ellps=airy" "nadgrids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif" "units=m" "no_defs" "type=crs" END
Definition: Mapnik
<?xml version="1.0" encoding="utf-8"?> <Map srs="+proj=ortho +lat_0=51.4701102238889 +lon_0=-0.451656585555556 +alpha=359.700932272222 +k=1.000002816 +x_0=7334.818 +y_0=5637.421 +ellps=airy +nadgrids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif +units=m +no_defs +type=crs"> <Layer srs="+proj=ortho +lat_0=51.4701102238889 +lon_0=-0.451656585555556 +alpha=359.700932272222 +k=1.000002816 +x_0=7334.818 +y_0=5637.421 +ellps=airy +nadgrids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif +units=m +no_defs +type=crs"> </Layer> </Map>
Definition: SQL (PostGIS)
INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 11390, 'EPSG', 11390, '+proj=ortho +lat_0=51.4701102238889 +lon_0=-0.451656585555556 +alpha=359.700932272222 +k=1.000002816 +x_0=7334.818 +y_0=5637.421 +ellps=airy +nadgrids=uk_os_OSTN15_NTv2_OSGBtoETRS.tif +units=m +no_defs +type=crs', 'PROJCS["OSGB36 / Heathrow Airport GIS Grid 2026",GEOGCS["OSGB36",DATUM["Ordnance_Survey_of_Great_Britain_1936",SPHEROID["Airy 1830",6377563.396,299.3249646],EXTENSION["PROJ4_GRIDS","uk_os_OSTN15_NTv2_OSGBtoETRS.tif"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4277"]],PROJECTION["Local Orthographic"],PARAMETER["latitude_of_center",51.4701102238889],PARAMETER["longitude_of_center",-0.451656585555556],PARAMETER["azimuth",359.700932272222],PARAMETER["scale_factor",1.000002816],PARAMETER["false_easting",7334.818],PARAMETER["false_northing",5637.421],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","11390"]]');
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