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A relative location is described as a displacement from another site—for example, "3 miles northwest of Seattle". A locality is likely to have a well-defined name but a boundary which is less well defined and which varies by context. London, for instance, has a legal boundary, but this is unlikely to completely match with general usage. An area within a town, such as Covent Garden in London, also almost always has some ambiguity as to its extent. Absolute location - An absolute location is designated using a specific pairing of latitude and longitude in a Cartesian coordinate grid—for example, a Spherical coordinate system or an ellipsoid-based system such as the World Geodetic System—or similar methods. An example would be the longitude and latitude of a place. For instance, the position of Lake Maracaibo in Venezuela can be expressed approximately in the WGS84 coordinate system as the location 9.80°N (latitude), 71.56°W (longitude). It is, however, important to remember that this is just one way to describe its position; a small number of the alternative ways can be seen in this link: 9.80°N 71.56°W. Absolute location, however, is a term which has little real meaning, since any location must be expressed relative to something else. For example, longitude is the number of degrees east or west of the Prime Meridian, a line which has arbitrarily been chosen to pass through Greenwich, London. Similarly, latitude is the number of degrees north or south of the Equator. Because latitude and longitude are expressed relative to these lines, a position expressed in latitude and longitude is actually a relative location.[1] |
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