World Geographic Reference System: Difference between revisions

Revision as of 00:32, 21 June 2008

Revision as of 00:15, 24 May 2009

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{{for|the bibliographic database about the geosciences|GeoRef}}

[[imageImage:georef-global.jpg|thumb|384px|right|The GEOREF Grid]]

'''Georef''' ('''World Geographic Reference System''') is a grid-based method of specifying locations on the surface of the [[Earth]]. Georef is essentially based on the geographic system of [[latitude]] and [[longitude]], but using a simpler and more flexible [[notation]]. Georef was used primarily for air navigation, particularly in military or inter-service applications, but it is rarely seen today. However, Georef can be used with any map or chart that has latitude and longitude printed on it.

== Operation ==

[[Georef]] is based on the standard system of [[latitude]] and [[longitude]], but uses a simpler and more concise notation. Georef divides the earth's surface into successively smaller quadrangles, with a notation system used to identify each quadrangle within its parent. Unlike latitude / longitude, Georef runs in one direction horizontally, east from the 180° [[meridian (geography)|meridian]]; and one direction vertically, north from the [[South Pole]]. Georef can easily be adapted to give co-ordinates with varying degrees of precision, using a 2-12 character [[geocode]].

Georef co-ordinates are defined by successive divisions of the Earth's surface, as follows:

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=== Example ===

[[imageImage:georef-local.jpg|thumb|256px|right|The GJ local grid]]

For example, on a GEOREF chart, [[Naval Air Station Patuxent River]] is located (to the nearest minute) at position GJPJ3716. <!-- Figure needed! In figure 12-10, the blacked-out square (PJ) within the enlarged 15° square (GJ) indicates the 1° area that contains Patuxent. -->