equator of an ellipsoid of revolution
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… …
2Figure of the Earth — An oblate spheroid Geodesy …
3Meridian arc — In geodesy, a meridian arc measurement is a highly accurate determination of the distance between two points with the same longitude. Two or more such determinations at different locations then specify the shape of the reference ellipsoid which… …
4Geodesy — (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… …
5History of geodesy — See also the main article on Geodesy. Humanity has always been interested in the Earth. During very early times this interest was limited, naturally, to the immediate vicinity of home and residency, and the fact that we live on a near spherical… …
6Latitude — This article is about the geographical reference system. For other uses, see Latitude (disambiguation). Map of Earth Longitude (λ) Lines of longitude appear vertical with varying curvature in this projection, but are actually halves of great… …
7Longitude — For Dava Sobel s book about John Harrison, see Longitude (book). For the adaptation of Sobel s book, see Longitude (TV series). Map of Earth Longitude (λ) Lines of longitude appear vertical with varying curvature in this projection, but are… …
8Clairaut's theorem — For the interpretation of this theorem in terms of symmetry of second derivatives of a mapping , see Symmetry of second derivatives. Figure 1: An ellipsoid …
9Spherical Earth — Medieval artistic representation of a spherical Earth with compartments representing earth, air, and water (c. 1400). The concept of a spherical Earth dates back to ancient Greek philosophy from around the 6th century BC …
10gravitation — gravitational, adj. gravitationally, adv. /grav i tay sheuhn/, n. 1. Physics. a. the force of attraction between any two masses. Cf. law of gravitation. b. an act or process caused by this force. 2. a sinking or falling …
