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The process of assigning a geographical reference to an object or feature. The term is most often applied narrowly to the assignment of latitude and longitude, or coordinates in some similarly general system, to records identified by street address, where it is synonymous with \'address matching\'. Geocoding is a necessary stage in mapping the incidence of disease, the customers of a business (see geodemographics), or calls to an emergency service. In most countries it is sufficient to know the coordinates of the endpoints of each link in the street network; the coordinates of a specific address can be estimated by interpolation. In some countries this is impossible because addresses are not numbered sequentially. Geocoding is more problematic in rural areas, and numerous other difficulties result in comparatively low success rates. Nevertheless, it is an important function of geographic information systems. The implications of widespread use of geocoding for personal privacy and surveillance have been discussed by Goss (1995) and Pickles (1995).
More broadly, geocoding refers to any system for assigning unique references to points on the Earth\'s surface (DeMers, 1997). In this wider sense it includes coordinate systems, which assign multidimensional identifiers to locations; the most important are latitude and longitude, based on angular measurements to the Equator and the Greenwich Meridian, and Universal Transverse Mercator (UTM) coordinates, based on a system of 60 longitude zones, and widely adopted in the military community. It also includes place-names, which identify location on the Earth to an accuracy depending on the size of the area covered by each place-name. The administrative hierarchy of nation, province, county, township, etc. also provides a system of coarse geocoding. The \'cadastre\', or system of land tenure, provides a form of geocoding. In the United States the Public Land Survey System, which is the basis of the cadastre for most of the nation, is the dominant system of geocoding for land management and many primary industries. (MG)
References DeMers, M.N. 1997 Fundamentals of geographic information systems. New York: Wiley. Goss, J.D. 1995: We know where you are and we know where you live. Economic Geography 71(2): 171-98. Pickles, J., ed., 1995: Ground truth: the social implications of geographic information systems. New York: Guilford. |
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