Encyclopedia
Quasigeoid
Quasi-geoid: geometric locus of points obtained by laying out normal heights along the force lines of the normal gravitational field from points on the physical surface of the Earth; heights of the quasi-geoid are measured from the surface of the ellipsoid
Source: "GEOGRAPHIC INFORMATION SYSTEMS. COORDINATE BASE. GENERAL REQUIREMENTS. GOST R 52572-2006"
(approved by Order of Rosstandart dated September 28, 2006 No. 215-st)