Clarke's foot
EPSG
"Ellipsoidisch Parameter der Erdfigur (1800-1950)" by Georg Strasser.
2008-06-26
Clarke gave a and b and also 1/f=293.465 (to 3 decimal places exactly). In the 19th century b was normally given as the second defining parameter.
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "Ellipsoid", "name": "Clarke 1880", "semi_major_axis": { "value": 20926202, "unit": { "type": "LinearUnit", "name": "Clarke's foot", "conversion_factor": 0.3047972654 } }, "semi_minor_axis": { "value": 20854895, "unit": { "type": "LinearUnit", "name": "Clarke's foot", "conversion_factor": 0.3047972654 } }, "id": { "authority": "EPSG", "code": 7034 } }