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abstraction > mathematical concept > geometrical object > point > coordinate

coordinate
subject			fact

coordinate	has component coordinate component
	has definition Quantities that provide references for locations in space and time.
	is a kind of point
point	has dimensions 0

Kinds of coordinate :

• co-moving coordinate (3 facts) - A set of coordinates which do not change in an expanding (or otherwise moving) medium. i.e. the coordinates of a distant galaxy do not change just because of the expansion of space., Coordinates fixed with respect to the overall Hubble flow of the universe, so that they do not change as the universe expands.
• ecliptic coordinate (1 kind, 6 facts) - A system of coordinates based on the plane defined by Earth's orbit around the Sun, which is inclined to the celestial equator.
• equatorial coordinate (6 kinds, 27 facts)
• galactic coordinate (5 kinds, 36 facts) - A system of coordinates based on the mean plane of the Galaxy, which is inclined about 63° to the celestial equator. Galactic latitude (b) is measured from the galactic equator north (+) or south (-); galactic longitude (l) is measured eastward along the galactic plane from the galactic center. In 1958, because of increased precision in determining the location of the galactic center, a new system of galactic coordinates was adopted, with the origin at the galactic center in Sagittarius at α(1950) = 17^h42^m.4, δ(1950) = - 28°55'. The new system is designated by a superior roman numeral II (i.e., b^II, l^II) and the old system by a superior roman numeral I: l^II ≈ l^I + 32^°.31. Galactic coordinates are independent of precession.
• geocentric coordinate (3 kinds, 22 facts) - The longitude and latitude of a point on the Earth relative to the geoid. These coordinates are influenced by local gravity anomalies., The latitude and longitude of a point on the Earth's surface relative to the center of the Earth; also celestial coordinates given with respect to the center of the Earth.
• geodetic coordinate (2 facts) - The latitude and longitude of a point on the Earth's surface determined from the geodetic vertical (normal to the specified spheroid). (See zenith; latitude, terrestrial; longitude, terrestrial.)
• local coordinate (4 kinds, 27 facts)
• planetocentric coordinate (2 facts) - Coordinates for general use, where the z-axis is the mean axis of rotation; the x-axis is the intersection of the planetary equator (normal to the z-axis through the center of mass) and an arbitrary prime meridian; and the y-axis completes a right-hand coordinate system. Longitude (see longitude, celestial) of a point is measured positive to the prime meridian as defined by rotational elements. Latitude (see latitude, celestial) of a point is the angle between the planetary equator and a line to the center of mass. The radius is measured from the center of mass to the surface point.
• planetographic coordinate (2 facts) - Coordinates for cartographic purposes dependent on an equipotential surface as a reference surface. Longitude (see longitude, celestial) of a point is measured in the direction opposite to the rotation (positive to the west for direct rotation) from the cartographic position of the prime meridian defined by a clearly observable surface feature. Latitude (see latitude, celestial) of a point is the angle between the planetary equator (normal to the z-axis and through the center of mass) and normal to the reference surface at the point. The height of a point is specified as the distance above a point with the same longitude and latitude on the reference surface.
• rotating coordinate (8 kinds, 27 facts)
• selenocentric coordinate (3 facts) - With reference to the center of the Moon.
• topocentric coordinate (2 facts) - With reference to, or pertaining to, a point on the surface of the Earth, usually with reference to a coordinate system.