Geodesy, cadastre, engineering survey, topographic mapping.
PD/83 is the realization of DHDN in Thuringen. It is the resultant of applying a transformation derived at 13 points on the border between East and West Germany to Pulkovo 1942/83 points in Thuringen.
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "GeodeticReferenceFrame", "name": "Potsdam Datum/83", "ellipsoid": { "name": "Bessel 1841", "semi_major_axis": 6377397.155, "inverse_flattening": 299.1528128 }, "scope": "Geodesy, cadastre, engineering survey, topographic mapping.", "area": "Germany - Thuringen.", "bbox": { "south_latitude": 50.2, "west_longitude": 9.92, "north_latitude": 51.64, "east_longitude": 12.56 }, "id": { "authority": "EPSG", "code": 6746 } }