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Universal Transverse Mercator Military Grid - 14070_187
Figure 9-15. 100,000-meter-square Indentification for the military grid reference system

Engineering Aid 1 - Advanced Structural engineering guide book
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Starting at the 180th meridian and progressing eastward  by  the  compass,  the  earth’s  surface  is  divided into   a   succession   of   north-south   zones,   each extending  for  6  degrees  of  longitude.  These  zones  are numbered from 1 through 60. Between latitude 80°S and 84°N, each zone is divided into a succession of east-west  rows,  each  containing  8  degrees  of  latitude, with the exception of the northernmost row, which contains 12 degrees of latitude. Rows are designated by the letters C through X, with the letters  I and O omitted.   The   lettering   system   begins   at   the southernmost row and proceeds north. For a particular zone-row area, the designation consists of first, the zone number and next, the row letter, such as 16S, which means row S in zone 16. The polar regions (that is, the areas above 84°N and below 80°S) have only two zones in each area. These  lie  on  either  side  of  the  0-degrees  and  180- degrees  meridian.  In  the  North  Polar  region,  the  half of the region that contains the west longitudes is zone Y; that containing the east longitudes is zone Z. No numbers  are  used  with  these  designations.  Similarly, in the South Polar region, the half containing the west longitudes  is  zone  A;  that  containing  the  east longitudes,  zone  B. In the UTM Military Grid System, a particular point on the earth is further identified by the  100,000- meter square in which it happens to lie. Each of the 6-degree  longitude  by  8-degree  latitude  zone-row areas   in   the   system   is   subdivided   into   squares measuring 100,000 meters on each side. Each north- south column of 100,000-meter squares is identified by  letter  as  follows.  Beginning  at  the  180th  meridian and  proceeding  eastward,  you  will  find  six  columns  of full squares in each 6-degree zone. Besides the full columns, usually partial columns also run along the zone meridians. The partial columns and full columns in the first three zones are lettered from  A through Z, again with the letters  I and O omitted. In the next time zones, the lettering systems begins over again. Observe, for example, figure 9-14, view B. This figure shows the zone-row areas in 1N, 2N, and 3N, and 1P, 2P, and 3P. The zone meridians shown are 180°W,  174°W,  168°W,  and  162°W;  the  zone-row parallels shown are the equator (0° latitude), 8°N, and 16°N. The first 100,000-meter-square column to the east  of  180  degrees  is  the  partial  column  A.  Next comes six full columns: B, C, D, E, F, and G. Then comes  partial  column  H,  to  the  west  of  the  zone meridian  174°W.  The  first  column  to  the  east  of  zone meridian 174°W is partial column J; then comes the full-size columns K, L, M, N, P, and Q, followed by partial column R. To the east of zone meridian 168°W, the first column is partial column S; then comes the six full columns T, U, V, W, X, and Y, and the partial column Z to the west of zone meridian 162°W. The  east-west  rows  of  100,000-meter  squares  are designated by the letters  A through V, again with  I and O omitted. For columns in the odd-numbered zones, the first row of squares north of the equator has the letter   designation   A;  for  columns  in  the  even- numbered zones, the first row of squares north of the equator has the letter designation  F. Rows  above  and below this row are designated alphabetically. The first row  south  of  the  equator  in  the  odd-numbered  zones, for example, has the letter designation V, while the first row south of the equator in the even-numbered zones has the letter designation  E. The   complete   designation   for   a   particular 100,000-meter square consists of the number-letter, zone-row  designation  plus  the  two-letter,  100,000- meter-square   designation.   For   example,   the designation  1NBA  means  the  first  full  square  east  of the  180th  meridian  and  north  of  the  equator  (square BA) in zone-row 1N, as shown in figure 9-14, view B. If you know the latitude and longitude of a certain point on the earth, you can determine the designation of the 100,000-meter square in which the point lies. Take Fort Knox, Kentucky, for example, which lies approximately  at  latitude                                longitude                You will find this latitude and longitude in figure 9-15. The point lies in column 16, row S, and 100,000-meter  square  ES;  therefore,  the  100,000- meter-square  designation  for  Fort  Knox,  Kentucky,  is 16SES. The   location   of   a   particular   point   within   a 100,000-meter  square  is  given  by  naming  the  grid coordinates  of  the  100-meter  square  (or,  for  more precise  location,  of  the  10-meter  square)  in  which  the point lies. Within each zone the point of origin for measuring   these   coordinates   is   the   point   of intersection between the zone central meridian and the equator. A false easting of 500,000 meters, instead of a value of O meters, is assigned to the  central meridian to avoid the use of west or negative east-west coordinates.   For   points   in   the   earth’s   Southern Hemisphere, the equator is assigned a false  northing of  10,000,000  meters  to  avoid  the  use  of  south  or negative north-south coordinates, and northing values decrease from the equator toward the South Pole. For points in the Northern Hemisphere, the equator has a coordinate  value  of  0  meters,  and  northing  values increase toward the North Pole. This procedure results in very large coordinate values  when  the  coordinates  are  referenced  to  the 9-14







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