Topographic mapping.
SAD69 uses GRS67 ellipsoid with 1/f to exactly 2 decimal places. Precision of ellipsoid entry increased from 2 to 5 dp with change id 97.252. Error introduced if not using the truncated precision is 0 to 31mm.
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "GeodeticReferenceFrame", "name": "South American Datum 1969", "ellipsoid": { "name": "GRS 1967", "semi_major_axis": 6378160, "inverse_flattening": 298.247167427 }, "scope": "Topographic mapping.", "area": "Brazil - onshore and offshore. In rest of South America - onshore north of approximately 45°S and Tierra del Fuego.", "bbox": { "south_latitude": -55.96, "west_longitude": -91.72, "north_latitude": 12.52, "east_longitude": -25.28 }, "id": { "authority": "EPSG", "code": 6291 } }