EPSG:6278

DATUM["OSGB_1970_SN",
    SPHEROID["Airy 1830",6377563.396,299.3249646,
        AUTHORITY["EPSG","7001"]],
    AUTHORITY["EPSG","6278"]]

DATUM["OSGB 1970 (SN)",
    ELLIPSOID["Airy 1830",6377563.396,299.3249646,
        LENGTHUNIT["metre",1]],
    ID["EPSG",6278]]

DATUM["D_OSGB_1970_SN",
    SPHEROID["Airy_1830",6377563.396,299.3249646]]

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "GeodeticReferenceFrame",
    "name": "OSGB 1970 (SN)",
    "ellipsoid": {
        "name": "Airy 1830",
        "semi_major_axis": 6377563.396,
        "inverse_flattening": 299.3249646
    },
    "scope": "Geodesy.",
    "area": "United Kingdom (UK) - Great Britain - England and Wales onshore, Scotland onshore and Western Isles nearshore including Sea of the Hebrides and The Minch; Isle of Man onshore.",
    "bbox": {
        "south_latitude": 49.79,
        "west_longitude": -8.82,
        "north_latitude": 60.94,
        "east_longitude": 1.92
    },
    "id": {
        "authority": "EPSG",
        "code": 6278
    }
}