Geodesy, cadastre, engineering survey, topographic mapping.
NAD27 (CGQ77) used in Quebec for all maps at scale 1/20 000 and larger; generally for maps issued by the Quebec cartography office whose reference system is CGQ77.
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "GeodeticReferenceFrame", "name": "North American Datum 1927 (CGQ77)", "ellipsoid": { "name": "Clarke 1866", "semi_major_axis": 6378206.4, "semi_minor_axis": 6356583.8 }, "scope": "Geodesy, cadastre, engineering survey, topographic mapping.", "area": "Canada - Quebec.", "bbox": { "south_latitude": 44.99, "west_longitude": -79.85, "north_latitude": 62.62, "east_longitude": -57.1 }, "id": { "authority": "EPSG", "code": 6609 } }