geoidal undulation
1geoid — geoidal, adj. /jee oyd/, n. 1. an imaginary surface that coincides with mean sea level in the ocean and its extension through the continents. 2. the geometric figure formed by this surface, an ellipsoid flattened at the poles. [1880 85; < Gk… …
2Vertical deflection — The vertical deflection (deflection of the plumb line, astro geodetic deflection) at a point on the earth is a measure of how far the direction of the local gravity field has been shifted by local anomalies such as nearby mountains. (Here gravity …
3Geodesy — (pronEng|dʒiːˈɒdɪsi [OED] ), also called geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three dimensional time varying… …
