Topographic mapping.
Replaced by Philippine Reference system of 1992 (datum code 6683).
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "GeodeticReferenceFrame", "name": "Luzon 1911", "ellipsoid": { "name": "Clarke 1866", "semi_major_axis": 6378206.4, "semi_minor_axis": 6356583.8 }, "scope": "Topographic mapping.", "area": "Philippines - onshore.", "bbox": { "south_latitude": 4.99, "west_longitude": 116.89, "north_latitude": 19.45, "east_longitude": 126.65 }, "id": { "authority": "EPSG", "code": 6253 } }