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The military grid reference system (MGRS)〔(DMA Technical Manual 8358.1, Chapter 3. ) Datums, Ellipsoids, Grids, and Grid Reference Systems〕 is the geocoordinate standard used by NATO militaries for locating points on the earth. The MGRS is derived from the Universal Transverse Mercator (UTM) grid system and the universal polar stereographic (UPS) grid system, but uses a different labeling convention. The MGRS is used for the entire earth. An example of an ''MGRS coordinate'', or ''grid reference'', would be (4QFJ12345678 ), which consists of three parts: * 4Q (grid zone designator, GZD) * FJ (the 100,000-meter square identifier) * 12345678 (numerical location; easting is 1234 and northing is 5678, in this case specifying a location with 10 m resolution) An MGRS grid reference is a point reference system. When the term 'grid square' is used, it can refer to a square with a side length of , 1 km, , 10 m or 1 m, depending on the precision of the coordinates provided. (In some cases, squares adjacent to a Grid Zone Junction (GZJ) are clipped, so polygon is a better descriptor of these areas.) The number of digits in the numerical location must be even: 0, 2, 4, 6, 8 or 10, depending on the desired precision. When changing precision levels, it is important to truncate rather than round the easting and northing values to ensure the more precise polygon will remain within the boundaries of the less precise polygon. Related to this is the primacy of the southwest corner of the polygon being the labeling point for an entire polygon. In instances where the polygon is not a square and has been clipped by a grid zone junction, the polygon keeps the label of the southwest corner as if it had not been clipped. * 4Q .....................GZD only, precision level 6° × 8° (in most cases) * 4QFJ ...................GZD and 100 km Grid Square ID, precision level 100 km * 4QFJ 1 6 ...............precision level 10 km * 4QFJ 12 67 .............precision level 1 km * 4QFJ 123 678 ...........precision level 100 m * 4QFJ 1234 6789 .........precision level 10 m * 4QFJ 12345 67890 .......precision level 1 m ==Grid zone designation== The first part of an MGRS coordinate is the ''grid-zone designation''. The 6° wide UTM zones, numbered 1–60, are intersected by latitude bands that are normally 8° high, lettered C–X (omitting I and O). The northmost latitude band, X, is 12° high. The intersection of a UTM zone and a latitude band is (normally) a 6° × 8° polygon called a ''grid zone'', whose ''designation'' in MGRS is formed by the zone number (one or two digits – the number for zones 1 to 9 is just a single digit, according to the example in DMA TM 8358.1, Section 3-2,〔 Figure 7), followed by the latitude band letter (uppercase). This same notation is used in both UTM and MGRS, i.e. the UTM grid reference system; the article on Universal Transverse Mercator shows many maps of these grid zones, including the irregularities for Svalbard and southwest Norway. As Figure 1 illustrates, Honolulu is in grid zone 4Q. 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「military grid reference system」の詳細全文を読む スポンサード リンク
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