Polar Definitions for Land Surveyors
polar area—A stereographic grid extending to 79°30′ N from the South Pole and to 79°30′ S from the North Pole, thus providing a 30′ overlap on the Universal Transverse Mercator grid.
polar axis—The primary axis of direction in a system of polar or spherical coordinates.
polar bearing—In a system of polar or spherical coordinates, the angle formed by the intersection of the reference meridional plane and the meridional plane containing the point.
polar distance-1 The astronomical coordinate (0° to 180°) measured from the pole of a planet or a star to a point along an hour circle; usually limited in actual use to mean codeclination. 2 The complement of the declination (co-declination) or 90° minus the declination. Polar distance forms one side of the astronomical triangle.
polar map projection—See map projection, polar
polar motion—1 The irregularly varying motion of the Earth’s pole of rotation with respect to the Earth’s crust. 2 The movement of the Earth’s instantaneous axis or rotation with respect to the axis of the figure of the Earth; wobble, wander.
polar symmetry—Symmetry in which parts are equal and interchangeable in all directions in planes perpendicular to a central axis but not in both directions from these planes.
Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.
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