Before revision: The SK-42 reference system also known as the Krasovsky ellipsoid, is a coordinate system established in the Soviet Union in 1942 as Systema koordinat (), and provides parameters which are linked to the geocentric Cartesian coordinate system PZ-90.
After revision: 1940The SK-42 reference system also known as the Krasovsky ellipsoid, is a coordinate system established in the Soviet Union in 1942 as Systema koordinat (), and provides parameters which are linked to the geocentric Cartesian coordinate system PZ-90.