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The Universal Transverse Mercator (UTM) conformal projection uses a 2-dimensional Cartesian coordinate system to give locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, i.e. it is used to identify locations on the Earth independently of vertical position. However, it differs from that method in several respects. The UTM system is not a single map projection. The system instead divides the Earth into sixty zones, each being a six-degree band of longitude, and uses a secant transverse Mercator projection in each zone. ==History== The Universal Transverse Mercator coordinate system was developed by the United States Army Corps of Engineers in the 1940s.〔http://www.history.noaa.gov/stories_tales/geod1.html〕 The system was based on an ellipsoidal model of Earth. For areas within the contiguous United States the Clarke Ellipsoid of 1866〔Equatorial radius 6,378,206.4 meters, polar radius 6,356,583.8 meters〕 was used. For the remaining areas of Earth, including Hawaii, the International Ellipsoid〔Equatorial radius 6,378,388 meters, reciprocal of the flattening 297 exactly〕 was used. The WGS84 ellipsoid is now generally used to model the Earth in the UTM coordinate system, which means current UTM northing at a given point can be 200+ meters different from the old. For different geographic regions, other datum systems (e.g.: ED50, NAD83) can be used. Prior to the development of the Universal Transverse Mercator coordinate system, several European nations demonstrated the utility of grid-based conformal maps by mapping their territory during the interwar period. Calculating the distance between two points on these maps could be performed more easily in the field (using the Pythagorean theorem) than was possible using the trigonometric formulas required under the graticule-based system of latitude and longitude. In the post-war years, these concepts were extended into the Universal Transverse Mercator / Universal Polar Stereographic (UTM/UPS) coordinate system, which is a global (or universal) system of grid-based maps. The transverse Mercator projection is a variant of the Mercator projection, which was originally developed by the Flemish geographer and cartographer Gerardus Mercator, in 1570. This projection is conformal, so it preserves angles and approximates shape but distorts distance and area. UTM involves non-linear anisotropic scaling in both easting and northing to ensure the projected map of the ellipsoid is conformal. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Universal Transverse Mercator coordinate system」の詳細全文を読む スポンサード リンク
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