{"$schema":"https://proj.org/schemas/v0.7/projjson.schema.json","type":"EngineeringDatum","name":"Heathrow Airport Grid","scope":"Engineering survey, topographic mapping.","area":"UK - Heathrow airport and surrounding area.","bbox":{"south_latitude":51.42,"west_longitude":-0.56,"north_latitude":51.52,"east_longitude":-0.37},"id":{"authority":"EPSG","code":1452}}