EPSG:27581 DEPRECATED

NTF (Paris) / France I

Selected transformation

Grid Files: gr3df97a.txt

Remarks: See transformation code 7811 for an alternative which uses the NTv2 method as an emulation of the geocentric interpolation in the second step.

Information source: IOGP

Revision date: 2021-09-08

Attributes

Unit: metre

Geodetic CRS: NTF (Paris)

Datum: Nouvelle Triangulation Francaise (Paris)

Ellipsoid: Clarke 1880 (IGN)

Prime meridian: Paris

Data source: EPSG

Revision date: 1996-04-12

Scope: Engineering survey, topographic mapping.

Remarks: Introduced 1972. Supersedes NTF / Nord France (code 27591).

Area of use: France mainland onshore north of 53.5 grads North (48°09'N).

Coordinate system: Cartesian 2D CS. Axes: easting, northing (X,Y). Orientations: east, north. UoM: m.

Center coordinates
inf inf

Projected bounds:
inf inf
inf inf

WGS84 bounds:
-4.87 41.31
9.63 51.14

France - onshore - mainland and Corsica.
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Definition: OGC Well Known Text 2 (2019)

BOUNDCRS[
    SOURCECRS[
        BOUNDCRS[
            SOURCECRS[
                PROJCRS["NTF (Paris) / France I",
                    BASEGEOGCRS["NTF (Paris)",
                        DATUM["Nouvelle Triangulation Francaise (Paris)",
                            ELLIPSOID["Clarke 1880 (IGN)",6378249.2,293.466021293627,
                                LENGTHUNIT["metre",1]]],
                        PRIMEM["Paris",2.5969213,
                            ANGLEUNIT["grad",0.0157079632679489]],
                        ID["EPSG",4807]],
                    CONVERSION["Lambert zone I",
                        METHOD["Lambert Conic Conformal (1SP)",
                            ID["EPSG",9801]],
                        PARAMETER["Latitude of natural origin",55,
                            ANGLEUNIT["grad",0.0157079632679489],
                            ID["EPSG",8801]],
                        PARAMETER["Longitude of natural origin",0,
                            ANGLEUNIT["grad",0.0157079632679489],
                            ID["EPSG",8802]],
                        PARAMETER["Scale factor at natural origin",0.999877341,
                            SCALEUNIT["unity",1],
                            ID["EPSG",8805]],
                        PARAMETER["False easting",600000,
                            LENGTHUNIT["metre",1],
                            ID["EPSG",8806]],
                        PARAMETER["False northing",1200000,
                            LENGTHUNIT["metre",1],
                            ID["EPSG",8807]]],
                    CS[Cartesian,2],
                        AXIS["easting (X)",east,
                            ORDER[1],
                            LENGTHUNIT["metre",1]],
                        AXIS["northing (Y)",north,
                            ORDER[2],
                            LENGTHUNIT["metre",1]],
                    ID["EPSG",27581]]],
            TARGETCRS[
                GEOGCRS["NTF",
                    DATUM["Nouvelle Triangulation Francaise",
                        ELLIPSOID["Clarke 1880 (IGN)",6378249.2,293.466021293627,
                            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",4275]]],
            ABRIDGEDTRANSFORMATION["NTF (Paris) to NTF (1)",
                METHOD["Longitude rotation",
                    ID["EPSG",9601]],
                PARAMETER["Longitude offset",8414.02501199997,
                    ID["EPSG",8602]],
                ID["EPSG",1763]]]],
    TARGETCRS[
        GEOGCRS["RGF93 v1",
            DATUM["Reseau Geodesique Francais 1993 v1",
                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]],
            USAGE[
                SCOPE["Horizontal component of 3D system."],
                AREA["France - onshore and offshore, mainland and Corsica (France métropolitaine including Corsica)."],
                BBOX[41.15,-9.86,51.56,10.38]],
            ID["EPSG",4171]]],
    ABRIDGEDTRANSFORMATION["NTF to RGF93 v1 (1)",
        METHOD["Geocentric translation by Grid Interpolation (IGN)",
            ID["EPSG",1087]],
        PARAMETERFILE["Geocentric translation file","gr3df97a.txt"],
        USAGE[
            SCOPE["Transformation of coordinates at 1m level of accuracy."],
            AREA["France - onshore - mainland and Corsica."],
            BBOX[41.31,-4.87,51.14,9.63]],
        ID["EPSG",9327],
        REMARK["May be emulated using NTv2 method - see tfm code 15958. Also used to transform between NTF and later realizations of RGF93."]]]

Definition: PROJ.4

+proj=lcc +lat_1=49.5 +lat_0=49.5 +lon_0=0 +k_0=0.999877341 +x_0=600000 +y_0=1200000 +ellps=clrk80ign +pm=paris +units=m +no_defs +type=crs

Definition: JavaScript (Proj4js)

proj4.defs("EPSG:27581","+proj=lcc +lat_1=49.5 +lat_0=49.5 +lon_0=0 +k_0=0.999877341 +x_0=600000 +y_0=1200000 +ellps=clrk80ign +pm=paris +units=m +no_defs +type=crs");

Definition: JSON

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "BoundCRS",
    "source_crs": {
        "type": "BoundCRS",
        "source_crs": {
            "type": "ProjectedCRS",
            "name": "NTF (Paris) / France I",
            "base_crs": {
                "name": "NTF (Paris)",
                "datum": {
                    "type": "GeodeticReferenceFrame",
                    "name": "Nouvelle Triangulation Francaise (Paris)",
                    "ellipsoid": {
                        "name": "Clarke 1880 (IGN)",
                        "semi_major_axis": 6378249.2,
                        "semi_minor_axis": 6356515
                    },
                    "prime_meridian": {
                        "name": "Paris",
                        "longitude": {
                            "value": 2.5969213,
                            "unit": {
                                "type": "AngularUnit",
                                "name": "grad",
                                "conversion_factor": 0.0157079632679489
                            }
                        }
                    }
                },
                "coordinate_system": {
                    "subtype": "ellipsoidal",
                    "axis": [
                        {
                            "name": "Geodetic latitude",
                            "abbreviation": "Lat",
                            "direction": "north",
                            "unit": {
                                "type": "AngularUnit",
                                "name": "grad",
                                "conversion_factor": 0.0157079632679489
                            }
                        },
                        {
                            "name": "Geodetic longitude",
                            "abbreviation": "Lon",
                            "direction": "east",
                            "unit": {
                                "type": "AngularUnit",
                                "name": "grad",
                                "conversion_factor": 0.0157079632679489
                            }
                        }
                    ]
                },
                "id": {
                    "authority": "EPSG",
                    "code": 4807
                }
            },
            "conversion": {
                "name": "Lambert zone I",
                "method": {
                    "name": "Lambert Conic Conformal (1SP)",
                    "id": {
                        "authority": "EPSG",
                        "code": 9801
                    }
                },
                "parameters": [
                    {
                        "name": "Latitude of natural origin",
                        "value": 55,
                        "unit": {
                            "type": "AngularUnit",
                            "name": "grad",
                            "conversion_factor": 0.0157079632679489
                        },
                        "id": {
                            "authority": "EPSG",
                            "code": 8801
                        }
                    },
                    {
                        "name": "Longitude of natural origin",
                        "value": 0,
                        "unit": {
                            "type": "AngularUnit",
                            "name": "grad",
                            "conversion_factor": 0.0157079632679489
                        },
                        "id": {
                            "authority": "EPSG",
                            "code": 8802
                        }
                    },
                    {
                        "name": "Scale factor at natural origin",
                        "value": 0.999877341,
                        "unit": "unity",
                        "id": {
                            "authority": "EPSG",
                            "code": 8805
                        }
                    },
                    {
                        "name": "False easting",
                        "value": 600000,
                        "unit": "metre",
                        "id": {
                            "authority": "EPSG",
                            "code": 8806
                        }
                    },
                    {
                        "name": "False northing",
                        "value": 1200000,
                        "unit": "metre",
                        "id": {
                            "authority": "EPSG",
                            "code": 8807
                        }
                    }
                ]
            },
            "coordinate_system": {
                "subtype": "Cartesian",
                "axis": [
                    {
                        "name": "Easting",
                        "abbreviation": "X",
                        "direction": "east",
                        "unit": "metre"
                    },
                    {
                        "name": "Northing",
                        "abbreviation": "Y",
                        "direction": "north",
                        "unit": "metre"
                    }
                ]
            },
            "id": {
                "authority": "EPSG",
                "code": 27581
            }
        },
        "target_crs": {
            "type": "GeographicCRS",
            "name": "NTF",
            "datum": {
                "type": "GeodeticReferenceFrame",
                "name": "Nouvelle Triangulation Francaise",
                "ellipsoid": {
                    "name": "Clarke 1880 (IGN)",
                    "semi_major_axis": 6378249.2,
                    "semi_minor_axis": 6356515
                }
            },
            "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": 4275
            }
        },
        "transformation": {
            "name": "NTF (Paris) to NTF (1)",
            "source_crs": {
                "type": "GeographicCRS",
                "name": "NTF (Paris) (with Greenwich prime meridian)",
                "datum": {
                    "type": "GeodeticReferenceFrame",
                    "name": "Nouvelle Triangulation Francaise (Paris) (with Greenwich prime meridian)",
                    "ellipsoid": {
                        "name": "Clarke 1880 (IGN)",
                        "semi_major_axis": 6378249.2,
                        "semi_minor_axis": 6356515
                    }
                },
                "coordinate_system": {
                    "subtype": "ellipsoidal",
                    "axis": [
                        {
                            "name": "Geodetic latitude",
                            "abbreviation": "Lat",
                            "direction": "north",
                            "unit": {
                                "type": "AngularUnit",
                                "name": "grad",
                                "conversion_factor": 0.0157079632679489
                            }
                        },
                        {
                            "name": "Geodetic longitude",
                            "abbreviation": "Lon",
                            "direction": "east",
                            "unit": {
                                "type": "AngularUnit",
                                "name": "grad",
                                "conversion_factor": 0.0157079632679489
                            }
                        }
                    ]
                }
            },
            "method": {
                "name": "Longitude rotation",
                "id": {
                    "authority": "EPSG",
                    "code": 9601
                }
            },
            "parameters": [
                {
                    "name": "Longitude offset",
                    "value": 2.5969213,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "grad",
                        "conversion_factor": 0.0157079632679489
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8602
                    }
                }
            ],
            "id": {
                "authority": "EPSG",
                "code": 1763
            }
        }
    },
    "target_crs": {
        "type": "GeographicCRS",
        "name": "RGF93 v1",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "Reseau Geodesique Francais 1993 v1",
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "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": 4171
        }
    },
    "transformation": {
        "name": "NTF to RGF93 v1 (1)",
        "source_crs": {
            "type": "GeographicCRS",
            "name": "NTF",
            "datum": {
                "type": "GeodeticReferenceFrame",
                "name": "Nouvelle Triangulation Francaise",
                "ellipsoid": {
                    "name": "Clarke 1880 (IGN)",
                    "semi_major_axis": 6378249.2,
                    "semi_minor_axis": 6356515
                }
            },
            "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": 4275
            }
        },
        "method": {
            "name": "Geocentric translation by Grid Interpolation (IGN)",
            "id": {
                "authority": "EPSG",
                "code": 1087
            }
        },
        "parameters": [
            {
                "name": "Geocentric translation file",
                "value": "gr3df97a.txt",
                "id": {
                    "authority": "EPSG",
                    "code": 8727
                }
            }
        ],
        "id": {
            "authority": "EPSG",
            "code": 9327
        }
    }
}

Definition: MapServer - MAPfile

PROJECTION
	"proj=lcc"
	"lat_1=49.5"
	"lat_0=49.5"
	"lon_0=0"
	"k_0=0.999877341"
	"x_0=600000"
	"y_0=1200000"
	"ellps=clrk80ign"
	"pm=paris"
	"units=m"
	"no_defs"
	"type=crs"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=lcc +lat_1=49.5 +lat_0=49.5 +lon_0=0 +k_0=0.999877341 +x_0=600000 +y_0=1200000 +ellps=clrk80ign +pm=paris +units=m +no_defs +type=crs">
	<Layer srs="+proj=lcc +lat_1=49.5 +lat_0=49.5 +lon_0=0 +k_0=0.999877341 +x_0=600000 +y_0=1200000 +ellps=clrk80ign +pm=paris +units=m +no_defs +type=crs">
	</Layer>
</Map>