EPSG:4421

NAD83 / BLM 1N (ftUS)

Available transformations
to EPSG:8246
EPSG:8246 - NAD83(CSRS)v4

Selected transformation

Name: NAD83 to NAD83(CSRS)v4 (9)

Method: NTv2

Grid Files: BC_93_05.GSB

Remarks: Derived through NAD83(CSRS)v4.

Information source: GeoBC, Government of British Columbia, via ISO Geodetic Register.

Revision date: 2026-02-10

Attributes

Unit: US survey foot

Geodetic CRS: NAD83

Datum: North American Datum 1983

Ellipsoid: GRS 1980

Prime meridian: Greenwich

Data source: EPSG

Information source: OGP

Revision date: 2011-06-30

Scope: No official usage.

Area of use: United States (USA) - between 180°W and 174°W - Alaska and offshore continental shelf (OCS).

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

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Center coordinates
11801728.87 23924513.45

Projected bounds:
8457308.8 20339649.11
15615068.89 27371134.6

WGS84 bounds:
-138.07 48.99
-114.33 60.01

Canada - British Columbia - mainland between 138°05'W and 114°20'W and Graham Island.
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Definition: OGC Well Known Text 2 (2019)

BOUNDCRS[
    SOURCECRS[
        PROJCRS["NAD83 / BLM 1N (ftUS)",
            BASEGEOGCRS["NAD83",
                DATUM["North American Datum 1983",
                    ELLIPSOID["GRS 1980",6378137,298.257222101,
                        LENGTHUNIT["metre",1]]],
                PRIMEM["Greenwich",0,
                    ANGLEUNIT["degree",0.0174532925199433]],
                ID["EPSG",4269]],
            CONVERSION["BLM zone 1N (US survey foot)",
                METHOD["Transverse Mercator",
                    ID["EPSG",9807]],
                PARAMETER["Latitude of natural origin",0,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8801]],
                PARAMETER["Longitude of natural origin",-177,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8802]],
                PARAMETER["Scale factor at natural origin",0.9996,
                    SCALEUNIT["unity",1],
                    ID["EPSG",8805]],
                PARAMETER["False easting",1640416.67,
                    LENGTHUNIT["US survey foot",0.304800609601219],
                    ID["EPSG",8806]],
                PARAMETER["False northing",0,
                    LENGTHUNIT["US survey foot",0.304800609601219],
                    ID["EPSG",8807]]],
            CS[Cartesian,2],
                AXIS["easting (X)",east,
                    ORDER[1],
                    LENGTHUNIT["US survey foot",0.304800609601219]],
                AXIS["northing (Y)",north,
                    ORDER[2],
                    LENGTHUNIT["US survey foot",0.304800609601219]],
            USAGE[
                SCOPE["No official usage."],
                AREA["United States (USA) - between 180°W and 174°W - Alaska and offshore continental shelf (OCS)."],
                BBOX[47.88,-180,63.21,-173.99]],
            ID["EPSG",4421]]],
    TARGETCRS[
        GEOGCRS["NAD83(CSRS)v4",
            DATUM["North American Datum of 1983 (CSRS) version 4",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]],
                ANCHOREPOCH[2002]],
            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["Canada - onshore and offshore - Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Northwest Territories; Nova Scotia; Nunavut; Ontario; Prince Edward Island; Quebec; Saskatchewan; Yukon."],
                BBOX[38.21,-141.01,86.46,-40.73]],
            ID["EPSG",8246],
            REMARK["Adopted by the Canadian federal government from 2002-01-01 and by the provincial governments of Alberta and British Columbia. Replaces NAD83(CSRS)v3. Replaced by NAD83(CSRS)v5 (CRS code 8249). Longitudes are POSITIVE EAST."]]],
    ABRIDGEDTRANSFORMATION["NAD83 to NAD83(CSRS)v4 (9)",
        METHOD["NTv2",
            ID["EPSG",9615]],
        PARAMETERFILE["Latitude and longitude difference file","BC_93_05.GSB"],
        USAGE[
            SCOPE["Geodesy."],
            AREA["Canada - British Columbia - mainland between 138°05'W and 114°20'W and Graham Island."],
            BBOX[48.99,-138.07,60.01,-114.33]],
        ID["EPSG",9119],
        REMARK["Derived through NAD83(CSRS)v4."]]]

Definition: PROJ.4

+proj=tmerc +lat_0=0 +lon_0=-177 +k=0.9996 +x_0=500000.001016002 +y_0=0 +datum=NAD83 +units=us-ft +no_defs +type=crs

Definition: JavaScript (Proj4js) 

proj4.defs("EPSG:4421","+proj=tmerc +lat_0=0 +lon_0=-177 +k=0.9996 +x_0=500000.001016002 +y_0=0 +datum=NAD83 +units=us-ft +no_defs +type=crs");

Definition: JSON

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "BoundCRS",
    "source_crs": {
        "type": "ProjectedCRS",
        "name": "NAD83 / BLM 1N (ftUS)",
        "base_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
            },
            "remarks": "Longitude is POSITIVE EAST. The adjustment included connections to Greenland and Mexico but the system was not adopted there. For applications with an accuracy of better than 1m replaced by NAD83(HARN) in the US and PRVI and by NAD83(CSRS) in Canada."
        },
        "conversion": {
            "name": "BLM zone 1N (US survey foot)",
            "method": {
                "name": "Transverse Mercator",
                "id": {
                    "authority": "EPSG",
                    "code": 9807
                }
            },
            "parameters": [
                {
                    "name": "Latitude of natural origin",
                    "value": 0,
                    "unit": "degree",
                    "id": {
                        "authority": "EPSG",
                        "code": 8801
                    }
                },
                {
                    "name": "Longitude of natural origin",
                    "value": -177,
                    "unit": "degree",
                    "id": {
                        "authority": "EPSG",
                        "code": 8802
                    }
                },
                {
                    "name": "Scale factor at natural origin",
                    "value": 0.9996,
                    "unit": "unity",
                    "id": {
                        "authority": "EPSG",
                        "code": 8805
                    }
                },
                {
                    "name": "False easting",
                    "value": 1640416.67,
                    "unit": {
                        "type": "LinearUnit",
                        "name": "US survey foot",
                        "conversion_factor": 0.304800609601219
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8806
                    }
                },
                {
                    "name": "False northing",
                    "value": 0,
                    "unit": {
                        "type": "LinearUnit",
                        "name": "US survey foot",
                        "conversion_factor": 0.304800609601219
                    },
                    "id": {
                        "authority": "EPSG",
                        "code": 8807
                    }
                }
            ]
        },
        "coordinate_system": {
            "subtype": "Cartesian",
            "axis": [
                {
                    "name": "Easting",
                    "abbreviation": "X",
                    "direction": "east",
                    "unit": {
                        "type": "LinearUnit",
                        "name": "US survey foot",
                        "conversion_factor": 0.304800609601219
                    }
                },
                {
                    "name": "Northing",
                    "abbreviation": "Y",
                    "direction": "north",
                    "unit": {
                        "type": "LinearUnit",
                        "name": "US survey foot",
                        "conversion_factor": 0.304800609601219
                    }
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4421
        }
    },
    "target_crs": {
        "type": "GeographicCRS",
        "name": "NAD83(CSRS)v4",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum of 1983 (CSRS) version 4",
            "anchor_epoch": 2002,
            "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": 8246
        },
        "remarks": "Adopted by the Canadian federal government from 2002-01-01 and by the provincial governments of Alberta and British Columbia. Replaces NAD83(CSRS)v3. Replaced by NAD83(CSRS)v5 (CRS code 8249). Longitudes are POSITIVE EAST."
    },
    "transformation": {
        "name": "NAD83 to NAD83(CSRS)v4 (9)",
        "method": {
            "name": "NTv2",
            "id": {
                "authority": "EPSG",
                "code": 9615
            }
        },
        "parameters": [
            {
                "name": "Latitude and longitude difference file",
                "value": "BC_93_05.GSB",
                "id": {
                    "authority": "EPSG",
                    "code": 8656
                }
            }
        ],
        "id": {
            "authority": "EPSG",
            "code": 9119
        }
    }
}

Definition: MapServer - MAPfile

PROJECTION
	"proj=tmerc"
	"lat_0=0"
	"lon_0=-177"
	"k=0.9996"
	"x_0=500000.001016002"
	"y_0=0"
	"datum=NAD83"
	"units=us-ft"
	"no_defs"
	"type=crs"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=tmerc +lat_0=0 +lon_0=-177 +k=0.9996 +x_0=500000.001016002 +y_0=0 +datum=NAD83 +units=us-ft +no_defs +type=crs">
	<Layer srs="+proj=tmerc +lat_0=0 +lon_0=-177 +k=0.9996 +x_0=500000.001016002 +y_0=0 +datum=NAD83 +units=us-ft +no_defs +type=crs">
	</Layer>
</Map>