An Etymological Dictionary of Astronomy and Astrophysics
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A type of Earth observing satellite used to measure the location of points on Earth's surface with great accuracy. Their observations help determine the exact size and shape of Earth, act as references for mapping, and track movements of Earth's crust.

→ geodesy; → satellite

Of, relating to, or determined by → geodesy.

→ geodesy; → -ic.

A → coordinate system, composed of → geodetic latitude and → geodetic longitude on the → Earth's surface which is dependent on the figure and size of a particular model for the Earth's surface.

→ geodetic; → coordinate.

Any of the adopted values of → geodetic latitude, → geodetic longitude, or → azimuth at a selected location (an initial station) whose astronomical coordinates have already been determined.

→ geodetic; → datum.

The plane swept out as the generating ellipse of the → reference ellipsoid rotates about its minor axis.

→ geodetic; → equator.

The → acute angle between the → geodetic vertical and the → geodetic equator.

→ geodetic; → latitude.

The angle between the plane of the → geodetic meridian and the plane of of the geodetic meridian through the site of the → Airy transit circle at the Royal Greenwich Observatory.

→ geodetic; → longitude.

The → ellipse through the point in question which passes through the → geodetic poles.

→ geodetic; → meridian.

Any of the small circles on the → reference ellipsoid parallel to the → geodetic equator.

→ geodetic; → parallel.

Any of the interaction points of the axis of revolution of the → reference ellipsoid with its surface.

→ geodetic; → pole.

A → relativistic effect on the precession motion of a gravitational system due to the → curvature of the → space-time. When a body revolves around a primary, the → rotation axis of the orbiting body follows the curvature of spece-time. Over time the space-time warping causes the spin axis to precess. In the case of the Earth-Moon system, this means a small → direct motion of the → equinox along the → ecliptic, amounting to 1''.915 per century. The geodetic precession is given by: ψ_g = (3/2) k² (1 - e_⊕) n_⊕, where k is the → constant of aberration (in radians), e_⊕ the → eccentricity of the Earth and n_⊕ the mean angular orbital motion of the Earth (in arcsec/cy). Also called → Einstein-de Sitter effect and → geodesic precession.

→ geodetic; → precession

The limiting case of → astronomical refraction when the light path is entirely within the Earth's atmosphere.

→ geodetic; → refraction.

The direction defined by the → normal to the → reference ellipsoid at the point in question.

→ geodetic; → vertical.

The intersection of the prolongation of the outward → normal to the → reference ellipsoid at the point in question with the → celestial sphere.

→ geodetic; → zenith.

Of or pertaining to → geography.

→ geography; → -ic.

A → ccordinate system on the surface of the Earth that defines every location by a set of numbers and letters, indicating the → latitude and → longitude.

→ geographic; → coordinate; → system.

A synonym for → geodetic latitude or → astronomical latitude.

→ geographic; → latitude.

→ north pole.

→ geographic; → north; → pole.

→ south pole.

→ geographic; → south; → pole.

The science dealing with the areal differentiation of the Earth's surface, as shown in the character, arrangement, and interrelations over the world of such elements as climate, elevation, soil, vegetation, population, land use, industries, or states, and of the unit areas formed by the complex of these individual elements (Dictionary.com).

→ geo-; → -graphy.