EPSG:4609

NAD27(CGQ77)

Transform Get position on a map

Available transformations
to EPSG:8237
EPSG:8237 - NAD83(CSRS)v2

  • Canada - Quebec. , accuracy 1.5 m, code 9240 (default) [grid]

Selected transformation

Method: NTv2

Grid Files: CGQ77-98.gsb

Remarks: Also found with file name CQ77SCRS.GSB. Uses NT method which expects longitudes positive west; EPSG GeogCRSs NAD27(CGQ77) (code 4609) and NAD83(CSRS) (code 4617) have longitudes positive east.

Information source: Geodetic Service of Quebec. Contact alain.bernard@mrn.gouv.qc.ca

Revision date: 2023-07-17

Attributes

Unit: degree (supplier to define representation)

Geodetic CRS: NAD27(CGQ77)

Datum: North American Datum 1927 (CGQ77)

Ellipsoid: Clarke 1866

Prime meridian: Greenwich

Data source: EPSG

Revision date: 2019-09-17

Scope: Geodesy.

Remarks: Note: this CRS includes longitudes which are POSITIVE EAST.

Area of use: Canada - Quebec.

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

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Center coordinates
-68.48 53.8

WGS84 bounds:
-79.85 44.99
-57.1 62.62

Canada - Quebec.
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Definition: OGC Well Known Text 2 (2019)

BOUNDCRS[
    SOURCECRS[
        GEOGCRS["NAD27(CGQ77)",
            DATUM["North American Datum 1927 (CGQ77)",
                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]],
            USAGE[
                SCOPE["Geodesy."],
                AREA["Canada - Quebec."],
                BBOX[44.99,-79.85,62.62,-57.1]],
            ID["EPSG",4609]]],
    TARGETCRS[
        GEOGCRS["NAD83(CSRS)v2",
            DATUM["North American Datum of 1983 (CSRS) version 2",
                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["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",8237]]],
    ABRIDGEDTRANSFORMATION["NAD27(CGQ77) to NAD83(CSRS)v2 (1)",
        METHOD["NTv2",
            ID["EPSG",9615]],
        PARAMETERFILE["Latitude and longitude difference file","CGQ77-98.gsb"],
        USAGE[
            SCOPE["Transformation of coordinates at 1m to 2m level of accuracy."],
            AREA["Canada - Quebec."],
            BBOX[44.99,-79.85,62.62,-57.1]],
        ID["EPSG",9240],
        REMARK["Also found with file name CQ77SCRS.GSB. Uses NT method which expects longitudes positive west; EPSG GeogCRSs NAD27(CGQ77) (code 4609) and NAD83(CSRS) (code 4617) have longitudes positive east."]]]

Definition: PROJ.4

+proj=longlat +ellps=clrk66 +no_defs +type=crs

Definition: JavaScript (Proj4js) 

proj4.defs("EPSG:4609","+proj=longlat +ellps=clrk66 +no_defs +type=crs");

Definition: JSON

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "BoundCRS",
    "source_crs": {
        "type": "GeographicCRS",
        "name": "NAD27(CGQ77)",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum 1927 (CGQ77)",
            "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": 4609
        }
    },
    "target_crs": {
        "type": "GeographicCRS",
        "name": "NAD83(CSRS)v2",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum of 1983 (CSRS) version 2",
            "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": 8237
        }
    },
    "transformation": {
        "name": "NAD27(CGQ77) to NAD83(CSRS)v2 (1)",
        "method": {
            "name": "NTv2",
            "id": {
                "authority": "EPSG",
                "code": 9615
            }
        },
        "parameters": [
            {
                "name": "Latitude and longitude difference file",
                "value": "CGQ77-98.gsb",
                "id": {
                    "authority": "EPSG",
                    "code": 8656
                }
            }
        ],
        "id": {
            "authority": "EPSG",
            "code": 9240
        }
    }
}

Definition: MapServer - MAPfile

PROJECTION
	"proj=longlat"
	"ellps=clrk66"
	"no_defs"
	"type=crs"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=longlat +ellps=clrk66 +no_defs +type=crs">
	<Layer srs="+proj=longlat +ellps=clrk66 +no_defs +type=crs">
	</Layer>
</Map>