Astro DOS 71 / SHLG71

St Helena, Ascension and Tristan da Cunha , accuracy 1.0 m, code 7894 (default) [3]
St Helena, Ascension and Tristan da Cunha , accuracy 44.0 m, code 15798 [3]

Selected transformation

Method: Geocentric translations (geog2D domain)

Remarks: Parameter values from Astro DOS 71 to SHGD2015 (1) (tfm code 7893). Assumes SHGD2015 and WGS 84 can be considered the same to within the accuracy of the transformation.

Information source: St. Helena Government, Environment and Natural Resources Directorate (ENRD).

Revision date: 2020-03-14

Attributes

Unit: metre

Geodetic CRS: Astro DOS 71

Datum: Astro DOS 71

Ellipsoid: International 1924

Prime meridian: Greenwich

Data source: EPSG

Information source: St. Helena Government, Environment and Natural Resources Directorate (ENRD).

Revision date: 2016-11-25

Scope: Topographic mapping.

Remarks: Replaced by SHMG2015 (CRS code 7887) from 2015.

Area of use: St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore.

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

Covered area powered by MapTiler

Center coordinates
299126.75 2000712.2

Projected bounds:
285201.69 1987981.8
313051.39 2013437.88

WGS84 bounds:
-5.85 -16.08
-5.59 -15.85

St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore.

Definition: OGC Well Known Text

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PROJCS["Astro DOS 71 / SHLG71",
    GEOGCS["Astro DOS 71",
        DATUM["Astro_DOS_71",
            SPHEROID["International 1924",6378388,297],
            TOWGS84[-323.65,551.39,-491.22,0,0,0,0]],
        PRIMEM["Greenwich",0,
            AUTHORITY["EPSG","8901"]],
        UNIT["degree",0.0174532925199433,
            AUTHORITY["EPSG","9122"]],
        AUTHORITY["EPSG","4710"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",-15.9666666666667],
    PARAMETER["central_meridian",-5.71666666666667],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",300000],
    PARAMETER["false_northing",2000000],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    AXIS["Easting",EAST],
    AXIS["Northing",NORTH],
    AUTHORITY["EPSG","7877"]]

Definition: OGC Well Known Text 2 (2019)

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PROJCRS["Astro DOS 71 / SHLG71",
    BASEGEOGCRS["Astro DOS 71",
        DATUM["Astro DOS 71",
            ELLIPSOID["International 1924",6378388,297,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4710]],
    CONVERSION["St. Helena Local Grid 1971",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",-15.9666666666667,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",-5.71666666666667,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",1,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",300000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",2000000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Topographic mapping."],
        AREA["St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore."],
        BBOX[-16.08,-5.85,-15.85,-5.59]],
    ID["EPSG",7877]]

Definition: ESRI Well Known Text

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PROJCS["Astro_DOS_71_4_SHLG71",
    GEOGCS["GCS_DOS_71_4",
        DATUM["D_DOS_71_4",
            SPHEROID["International_1924",6378388.0,297.0]],
        PRIMEM["Greenwich",0.0],
        UNIT["Degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["False_Easting",300000.0],
    PARAMETER["False_Northing",2000000.0],
    PARAMETER["Central_Meridian",-5.71666666666667],
    PARAMETER["Scale_Factor",1.0],
    PARAMETER["Latitude_Of_Origin",-15.9666666666667],
    UNIT["Meter",1.0]]

Definition: PROJ.4

+proj=tmerc +lat_0=-15.9666666666667 +lon_0=-5.71666666666667 +k=1 +x_0=300000 +y_0=2000000 +ellps=intl +towgs84=-323.65,551.39,-491.22,0,0,0,0 +units=m +no_defs +type=crs

Definition: JavaScript (Proj4js)

proj4.defs("EPSG:7877","+proj=tmerc +lat_0=-15.9666666666667 +lon_0=-5.71666666666667 +k=1 +x_0=300000 +y_0=2000000 +ellps=intl +towgs84=-323.65,551.39,-491.22,0,0,0,0 +units=m +no_defs +type=crs");

Definition: JSON

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{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "ProjectedCRS",
    "name": "Astro DOS 71 / SHLG71",
    "base_crs": {
        "name": "Astro DOS 71",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "Astro DOS 71",
            "ellipsoid": {
                "name": "International 1924",
                "semi_major_axis": 6378388,
                "inverse_flattening": 297
            }
        },
        "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": 4710
        }
    },
    "conversion": {
        "name": "St. Helena Local Grid 1971",
        "method": {
            "name": "Transverse Mercator",
            "id": {
                "authority": "EPSG",
                "code": 9807
            }
        },
        "parameters": [
            {
                "name": "Latitude of natural origin",
                "value": -15.9666666666667,
                "unit": "degree",
                "id": {
                    "authority": "EPSG",
                    "code": 8801
                }
            },
            {
                "name": "Longitude of natural origin",
                "value": -5.71666666666667,
                "unit": "degree",
                "id": {
                    "authority": "EPSG",
                    "code": 8802
                }
            },
            {
                "name": "Scale factor at natural origin",
                "value": 1,
                "unit": "unity",
                "id": {
                    "authority": "EPSG",
                    "code": 8805
                }
            },
            {
                "name": "False easting",
                "value": 300000,
                "unit": "metre",
                "id": {
                    "authority": "EPSG",
                    "code": 8806
                }
            },
            {
                "name": "False northing",
                "value": 2000000,
                "unit": "metre",
                "id": {
                    "authority": "EPSG",
                    "code": 8807
                }
            }
        ]
    },
    "coordinate_system": {
        "subtype": "Cartesian",
        "axis": [
            {
                "name": "Easting",
                "abbreviation": "E",
                "direction": "east",
                "unit": "metre"
            },
            {
                "name": "Northing",
                "abbreviation": "N",
                "direction": "north",
                "unit": "metre"
            }
        ]
    },
    "scope": "Topographic mapping.",
    "area": "St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore.",
    "bbox": {
        "south_latitude": -16.08,
        "west_longitude": -5.85,
        "north_latitude": -15.85,
        "east_longitude": -5.59
    },
    "id": {
        "authority": "EPSG",
        "code": 7877
    }
}

Definition: GeoServer

7877=PROJCS["Astro DOS 71 / SHLG71",GEOGCS["Astro DOS 71",DATUM["Astro_DOS_71",SPHEROID["International 1924",6378388,297],TOWGS84[-323.65,551.39,-491.22,0,0,0,0]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4710"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",-15.9666666666667],PARAMETER["central_meridian",-5.71666666666667],PARAMETER["scale_factor",1],PARAMETER["false_easting",300000],PARAMETER["false_northing",2000000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","7877"]]

Definition: MapServer - MAPfile

PROJECTION
	"proj=tmerc"
	"lat_0=-15.9666666666667"
	"lon_0=-5.71666666666667"
	"k=1"
	"x_0=300000"
	"y_0=2000000"
	"ellps=intl"
	"towgs84=-323.65,551.39,-491.22,0,0,0,0"
	"units=m"
	"no_defs"
	"type=crs"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=tmerc +lat_0=-15.9666666666667 +lon_0=-5.71666666666667 +k=1 +x_0=300000 +y_0=2000000 +ellps=intl +towgs84=-323.65,551.39,-491.22,0,0,0,0 +units=m +no_defs +type=crs">
	<Layer srs="+proj=tmerc +lat_0=-15.9666666666667 +lon_0=-5.71666666666667 +k=1 +x_0=300000 +y_0=2000000 +ellps=intl +towgs84=-323.65,551.39,-491.22,0,0,0,0 +units=m +no_defs +type=crs">
	</Layer>
</Map>

Definition: SQL (PostGIS)

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 7877, 'EPSG', 7877, '+proj=tmerc +lat_0=-15.9666666666667 +lon_0=-5.71666666666667 +k=1 +x_0=300000 +y_0=2000000 +ellps=intl +towgs84=-323.65,551.39,-491.22,0,0,0,0 +units=m +no_defs +type=crs', 'PROJCS["Astro DOS 71 / SHLG71",GEOGCS["Astro DOS 71",DATUM["Astro_DOS_71",SPHEROID["International 1924",6378388,297],TOWGS84[-323.65,551.39,-491.22,0,0,0,0]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4710"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",-15.9666666666667],PARAMETER["central_meridian",-5.71666666666667],PARAMETER["scale_factor",1],PARAMETER["false_easting",300000],PARAMETER["false_northing",2000000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","7877"]]');

EPSG:7877