EPSG:4267

NAD27

Selected transformation

Grid Files: conus.las conus.los

Remarks: For use with legacy data - see CT code 9104 for alternative for new areas. Note that steps 1 and 2 are documented in the geog2D domain, steps 3 and 4 in the geocentric domain. Steps 3 and 4 may be implemented in one operation using CT code 8970.

Information source: IOGP

Revision date: 2019-06-13

Attributes

Unit: degree (supplier to define representation)

Geodetic CRS: NAD27

Datum: North American Datum 1927

Ellipsoid: Clarke 1866

Prime meridian: Greenwich

Data source: EPSG

Revision date: 2022-12-12

Scope: Geodesy.

Remarks: Note: this CRS includes longitudes which are POSITIVE EAST. Replaced by NAD27(76) (code 4608) in Ontario, CGQ77 (code 4609) in Quebec, Mexican Datum of 1993 (code 4483) in Mexico, NAD83 (code 4269) in Canada (excl. Ontario & Quebec) & USA.

Area of use: North and central America: Antigua and Barbuda - onshore. Bahamas - onshore plus offshore over internal continental shelf only. Belize - onshore. British Virgin Islands - onshore. Canada onshore - Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward Island, Quebec, Saskatchewan and Yukon - plus offshore east coast. Cuba - onshore and offshore. El Salvador - onshore. Guatemala - onshore. Honduras - onshore. Panama - onshore. Puerto Rico - onshore. Mexico - onshore plus offshore east coast. Nicaragua - onshore. United States (USA) onshore and offshore - Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming - plus offshore . US Virgin Islands - onshore.

Coordinate system: Ellipsoidal 2D CS. Axes: latitude, longitude. Orientations: north, east. UoM: degree

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Definition: OGC Well Known Text 2 (2019)

BOUNDCRS[
    SOURCECRS[
        BOUNDCRS[
            SOURCECRS[
                BOUNDCRS[
                    SOURCECRS[
                        BOUNDCRS[
                            SOURCECRS[
                                GEOGCRS["NAD27",
                                    DATUM["North American Datum 1927",
                                        ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
                                            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",4267]]],
                            TARGETCRS[
                                GEOGCRS["NAD83",
                                    DATUM["North American Datum 1983",
                                        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]],
                                    ID["EPSG",4269]]],
                            ABRIDGEDTRANSFORMATION["NAD27 to NAD83 (1)",
                                METHOD["NADCON",
                                    ID["EPSG",9613]],
                                PARAMETERFILE["Latitude difference file","conus.las"],
                                PARAMETERFILE["Longitude difference file","conus.los"],
                                ID["EPSG",1241]]]],
                    TARGETCRS[
                        GEOGCRS["NAD83(2011)",
                            DATUM["NAD83 (National Spatial Reference System 2011)",
                                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]],
                            ID["EPSG",6318]]],
                    ABRIDGEDTRANSFORMATION["NAD83 to NAD83(2011) (1)",
                        METHOD["Geocentric translations (geog2D domain)",
                            ID["EPSG",9603]],
                        PARAMETER["X-axis translation",0,
                            ID["EPSG",8605]],
                        PARAMETER["Y-axis translation",0,
                            ID["EPSG",8606]],
                        PARAMETER["Z-axis translation",0,
                            ID["EPSG",8607]],
                        ID["EPSG",8971]]]],
            TARGETCRS[
                GEODCRS["ITRF2008",
                    DYNAMIC[
                        FRAMEEPOCH[2005]],
                    DATUM["International Terrestrial Reference Frame 2008",
                        ELLIPSOID["GRS 1980",6378137,298.257222101,
                            LENGTHUNIT["metre",1]]],
                    PRIMEM["Greenwich",0,
                        ANGLEUNIT["degree",0.0174532925199433]],
                    CS[Cartesian,3],
                        AXIS["(X)",geocentricX,
                            ORDER[1],
                            LENGTHUNIT["metre",1]],
                        AXIS["(Y)",geocentricY,
                            ORDER[2],
                            LENGTHUNIT["metre",1]],
                        AXIS["(Z)",geocentricZ,
                            ORDER[3],
                            LENGTHUNIT["metre",1]],
                    ID["EPSG",5332]]],
            ABRIDGEDTRANSFORMATION["Inverse of ITRF2008 to NAD83(2011) (1)",
                METHOD["Inverse of Time-dependent Coordinate Frame rotation (geocen)",
                    ID["INVERSE(EPSG)",1056]],
                PARAMETER["X-axis translation",0.99343,
                    ID["EPSG",8605]],
                PARAMETER["Y-axis translation",-1.90331,
                    ID["EPSG",8606]],
                PARAMETER["Z-axis translation",-0.52655,
                    ID["EPSG",8607]],
                PARAMETER["X-axis rotation",0.02591467,
                    ID["EPSG",8608]],
                PARAMETER["Y-axis rotation",0.00942645,
                    ID["EPSG",8609]],
                PARAMETER["Z-axis rotation",0.01159935,
                    ID["EPSG",8610]],
                PARAMETER["Scale difference",1.71504,
                    ID["EPSG",8611]],
                PARAMETER["Rate of change of X-axis translation",2.50341244864579E-11,
                    ID["EPSG",1040]],
                PARAMETER["Rate of change of Y-axis translation",-1.90132591036389E-11,
                    ID["EPSG",1041]],
                PARAMETER["Rate of change of Z-axis translation",-4.24629453314602E-11,
                    ID["EPSG",1042]],
                PARAMETER["Rate of change of X-axis rotation",2.11268997406601E-12,
                    ID["EPSG",1043]],
                PARAMETER["Rate of change of Y-axis rotation",-2.40023382924337E-11,
                    ID["EPSG",1044]],
                PARAMETER["Rate of change of Z-axis rotation",-1.62658431631631E-12,
                    ID["EPSG",1045]],
                PARAMETER["Rate of change of Scale difference",-0.10201,
                    ID["EPSG",1046]],
                PARAMETER["Parameter reference epoch",1997,
                    ID["EPSG",1047]],
                ID["INVERSE(EPSG)",7807]]]],
    TARGETCRS[
        GEODCRS["ITRF2014",
            DYNAMIC[
                FRAMEEPOCH[2010]],
            DATUM["International Terrestrial Reference Frame 2014",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[Cartesian,3],
                AXIS["(X)",geocentricX,
                    ORDER[1],
                    LENGTHUNIT["metre",1]],
                AXIS["(Y)",geocentricY,
                    ORDER[2],
                    LENGTHUNIT["metre",1]],
                AXIS["(Z)",geocentricZ,
                    ORDER[3],
                    LENGTHUNIT["metre",1]],
            USAGE[
                SCOPE["Geodesy."],
                AREA["World."],
                BBOX[-90,-180,90,180]],
            ID["EPSG",7789]]],
    ABRIDGEDTRANSFORMATION["ITRF2008 to ITRF2014 (1)",
        METHOD["Time-dependent Position Vector tfm (geocentric)",
            ID["EPSG",1053]],
        PARAMETER["X-axis translation",-0.0016,
            ID["EPSG",8605]],
        PARAMETER["Y-axis translation",-0.0019,
            ID["EPSG",8606]],
        PARAMETER["Z-axis translation",-0.0024,
            ID["EPSG",8607]],
        PARAMETER["X-axis rotation",0,
            ID["EPSG",8608]],
        PARAMETER["Y-axis rotation",0,
            ID["EPSG",8609]],
        PARAMETER["Z-axis rotation",0,
            ID["EPSG",8610]],
        PARAMETER["Scale difference",0.02,
            ID["EPSG",8611]],
        PARAMETER["Rate of change of X-axis translation",0,
            ID["EPSG",1040]],
        PARAMETER["Rate of change of Y-axis translation",0,
            ID["EPSG",1041]],
        PARAMETER["Rate of change of Z-axis translation",3.16887651727315E-12,
            ID["EPSG",1042]],
        PARAMETER["Rate of change of X-axis rotation",0,
            ID["EPSG",1043]],
        PARAMETER["Rate of change of Y-axis rotation",0,
            ID["EPSG",1044]],
        PARAMETER["Rate of change of Z-axis rotation",0,
            ID["EPSG",1045]],
        PARAMETER["Rate of change of Scale difference",-0.03,
            ID["EPSG",1046]],
        PARAMETER["Parameter reference epoch",2010,
            ID["EPSG",1047]],
        USAGE[
            SCOPE["Geodesy."],
            AREA["World."],
            BBOX[-90,-180,90,180]],
        ID["EPSG",7790],
        REMARK["Scale difference in ppb and scale difference rate in ppb/yr where 1/billion = 1E-9 or nm/m. Estimated using 127 stations at 125 sites."]]]

Definition: PROJ.4

+proj=longlat +datum=NAD27 +no_defs +type=crs

Definition: JavaScript (Proj4js)

proj4.defs("EPSG:4267","+proj=longlat +datum=NAD27 +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": "BoundCRS",
            "source_crs": {
                "type": "BoundCRS",
                "source_crs": {
                    "type": "GeographicCRS",
                    "name": "NAD27",
                    "datum": {
                        "type": "GeodeticReferenceFrame",
                        "name": "North American Datum 1927",
                        "ellipsoid": {
                            "name": "Clarke 1866",
                            "semi_major_axis": 6378206.4,
                            "semi_minor_axis": 6356583.8
                        }
                    },
                    "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": 4267
                    }
                },
                "target_crs": {
                    "type": "GeographicCRS",
                    "name": "NAD83",
                    "datum": {
                        "type": "GeodeticReferenceFrame",
                        "name": "North American Datum 1983",
                        "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": 4269
                    }
                },
                "transformation": {
                    "name": "NAD27 to NAD83 (1)",
                    "method": {
                        "name": "NADCON",
                        "id": {
                            "authority": "EPSG",
                            "code": 9613
                        }
                    },
                    "parameters": [
                        {
                            "name": "Latitude difference file",
                            "value": "conus.las",
                            "id": {
                                "authority": "EPSG",
                                "code": 8657
                            }
                        },
                        {
                            "name": "Longitude difference file",
                            "value": "conus.los",
                            "id": {
                                "authority": "EPSG",
                                "code": 8658
                            }
                        }
                    ],
                    "id": {
                        "authority": "EPSG",
                        "code": 1241
                    }
                }
            },
            "target_crs": {
                "type": "GeographicCRS",
                "name": "NAD83(2011)",
                "datum": {
                    "type": "GeodeticReferenceFrame",
                    "name": "NAD83 (National Spatial Reference System 2011)",
                    "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": 6318
                }
            },
            "transformation": {
                "name": "NAD83 to NAD83(2011) (1)",
                "source_crs": {
                    "type": "GeographicCRS",
                    "name": "NAD83",
                    "datum": {
                        "type": "GeodeticReferenceFrame",
                        "name": "North American Datum 1983",
                        "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": 4269
                    }
                },
                "method": {
                    "name": "Geocentric translations (geog2D domain)",
                    "id": {
                        "authority": "EPSG",
                        "code": 9603
                    }
                },
                "parameters": [
                    {
                        "name": "X-axis translation",
                        "value": 0,
                        "unit": "metre",
                        "id": {
                            "authority": "EPSG",
                            "code": 8605
                        }
                    },
                    {
                        "name": "Y-axis translation",
                        "value": 0,
                        "unit": "metre",
                        "id": {
                            "authority": "EPSG",
                            "code": 8606
                        }
                    },
                    {
                        "name": "Z-axis translation",
                        "value": 0,
                        "unit": "metre",
                        "id": {
                            "authority": "EPSG",
                            "code": 8607
                        }
                    }
                ],
                "id": {
                    "authority": "EPSG",
                    "code": 8971
                }
            }
        },
        "target_crs": {
            "type": "GeodeticCRS",
            "name": "ITRF2008",
            "datum": {
                "type": "DynamicGeodeticReferenceFrame",
                "name": "International Terrestrial Reference Frame 2008",
                "frame_reference_epoch": 2005,
                "ellipsoid": {
                    "name": "GRS 1980",
                    "semi_major_axis": 6378137,
                    "inverse_flattening": 298.257222101
                }
            },
            "coordinate_system": {
                "subtype": "Cartesian",
                "axis": [
                    {
                        "name": "Geocentric X",
                        "abbreviation": "X",
                        "direction": "geocentricX",
                        "unit": "metre"
                    },
                    {
                        "name": "Geocentric Y",
                        "abbreviation": "Y",
                        "direction": "geocentricY",
                        "unit": "metre"
                    },
                    {
                        "name": "Geocentric Z",
                        "abbreviation": "Z",
                        "direction": "geocentricZ",
                        "unit": "metre"
                    }
                ]
            },
            "id": {
                "authority": "EPSG",
                "code": 5332
            }
        },
        "transformation": {
            "name": "Inverse of ITRF2008 to NAD83(2011) (1)",
            "source_crs": {
                "type": "GeodeticCRS",
                "name": "NAD83(2011)",
                "datum": {
                    "type": "GeodeticReferenceFrame",
                    "name": "NAD83 (National Spatial Reference System 2011)",
                    "ellipsoid": {
                        "name": "GRS 1980",
                        "semi_major_axis": 6378137,
                        "inverse_flattening": 298.257222101
                    }
                },
                "coordinate_system": {
                    "subtype": "Cartesian",
                    "axis": [
                        {
                            "name": "Geocentric X",
                            "abbreviation": "X",
                            "direction": "geocentricX",
                            "unit": "metre"
                        },
                        {
                            "name": "Geocentric Y",
                            "abbreviation": "Y",
                            "direction": "geocentricY",
                            "unit": "metre"
                        },
                        {
                            "name": "Geocentric Z",
                            "abbreviation": "Z",
                            "direction": "geocentricZ",
                            "unit": "metre"
                        }
                    ]
                },
                "id": {
                    "authority": "EPSG",
                    "code": 6317
                }
            },
            "method": {
                "name": "Inverse of Time-dependent Coordinate Frame rotation (geocen)",
                "id": {
                    "authority": "INVERSE(EPSG)",
                    "code": 1056
                }
            },
            "parameters": [
                {
                    "name": "X-axis translation",
                    "value": 0.99343,
                    "unit": "metre",
                    "id": {
                        "authority": "EPSG",
                        "code": 8605
                    }
                },
                {
                    "name": "Y-axis translation",
                    "value": -1.90331,
                    "unit": "metre",
                    "id": {
                        "authority": "EPSG",
                        "code": 8606
                    }
                },
                {
                    "name": "Z-axis translation",
                    "value": -0.52655,
                    "unit": "metre",
                    "id": {
                        "authority": "EPSG",
                        "code": 8607
                    }
                },
                {
                    "name": "X-axis rotation",
                    "value": 25.91467,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-second",
                        "conversion_factor": 4.84813681109536e-09
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8608
                    }
                },
                {
                    "name": "Y-axis rotation",
                    "value": 9.42645,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-second",
                        "conversion_factor": 4.84813681109536e-09
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8609
                    }
                },
                {
                    "name": "Z-axis rotation",
                    "value": 11.59935,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-second",
                        "conversion_factor": 4.84813681109536e-09
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8610
                    }
                },
                {
                    "name": "Scale difference",
                    "value": 1.71504,
                    "unit": {
                        "type": "ScaleUnit",
                        "name": "parts per billion",
                        "conversion_factor": 1e-09
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8611
                    }
                },
                {
                    "name": "Rate of change of X-axis translation",
                    "value": 0.00079,
                    "unit": {
                        "type": "LinearUnit",
                        "name": "metres per year",
                        "conversion_factor": 3.16887651727315e-08
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1040
                    }
                },
                {
                    "name": "Rate of change of Y-axis translation",
                    "value": -0.0006,
                    "unit": {
                        "type": "LinearUnit",
                        "name": "metres per year",
                        "conversion_factor": 3.16887651727315e-08
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1041
                    }
                },
                {
                    "name": "Rate of change of Z-axis translation",
                    "value": -0.00134,
                    "unit": {
                        "type": "LinearUnit",
                        "name": "metres per year",
                        "conversion_factor": 3.16887651727315e-08
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1042
                    }
                },
                {
                    "name": "Rate of change of X-axis rotation",
                    "value": 0.06667,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-seconds per year",
                        "conversion_factor": 1.53631468932076e-16
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1043
                    }
                },
                {
                    "name": "Rate of change of Y-axis rotation",
                    "value": -0.75744,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-seconds per year",
                        "conversion_factor": 1.53631468932076e-16
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1044
                    }
                },
                {
                    "name": "Rate of change of Z-axis rotation",
                    "value": -0.05133,
                    "unit": {
                        "type": "AngularUnit",
                        "name": "milliarc-seconds per year",
                        "conversion_factor": 1.53631468932076e-16
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1045
                    }
                },
                {
                    "name": "Rate of change of Scale difference",
                    "value": -0.10201,
                    "unit": {
                        "type": "ScaleUnit",
                        "name": "parts per billion per year",
                        "conversion_factor": 3.16887651727315e-17
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1046
                    }
                },
                {
                    "name": "Parameter reference epoch",
                    "value": 1997,
                    "unit": {
                        "type": "TimeUnit",
                        "name": "year",
                        "conversion_factor": 31556925.445
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 1047
                    }
                }
            ],
            "id": {
                "authority": "INVERSE(EPSG)",
                "code": 7807
            }
        }
    },
    "target_crs": {
        "type": "GeodeticCRS",
        "name": "ITRF2014",
        "datum": {
            "type": "DynamicGeodeticReferenceFrame",
            "name": "International Terrestrial Reference Frame 2014",
            "frame_reference_epoch": 2010,
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "coordinate_system": {
            "subtype": "Cartesian",
            "axis": [
                {
                    "name": "Geocentric X",
                    "abbreviation": "X",
                    "direction": "geocentricX",
                    "unit": "metre"
                },
                {
                    "name": "Geocentric Y",
                    "abbreviation": "Y",
                    "direction": "geocentricY",
                    "unit": "metre"
                },
                {
                    "name": "Geocentric Z",
                    "abbreviation": "Z",
                    "direction": "geocentricZ",
                    "unit": "metre"
                }
            ]
        },
        "id": {
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                        "name": "Geocentric X",
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                        "direction": "geocentricX",
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                    {
                        "name": "Geocentric Y",
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                "name": "Rate of change of X-axis translation",
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                "name": "Rate of change of Y-axis translation",
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            {
                "name": "Rate of change of Z-axis translation",
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            {
                "name": "Rate of change of X-axis rotation",
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            {
                "name": "Rate of change of Y-axis rotation",
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            {
                "name": "Rate of change of Z-axis rotation",
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                "name": "Rate of change of Scale difference",
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                "name": "Parameter reference epoch",
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}

Definition: MapServer - MAPfile

PROJECTION
	"proj=longlat"
	"datum=NAD27"
	"no_defs"
	"type=crs"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	<Layer srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	</Layer>
</Map>