In conventional geodetic systems, locations of points on the surface of the Earth may be defined either by means of natural (astronomic) or geometric gepdetic cooprdinates. The natural coordinates, the astronomic latitude (Φ), longitude (λ), and the orthometric (mean sea level) height (H), being gravity dependent, are conventionally referenced, to the geoid and are determined from “natural” observations (astronomic, gravimetric observations and spirit leveling). The geometric coordinates, the geodetic latitude (φ), longitude (λ) and height (h) are referenced to a (generally) rotational ellipsoid of arbitrary size, shape and orientation, and are determined from geometric (length and/or direction) observations.
