![]() ![]() Among projections, UTM (Universal Transverse Mercator) seems to be used most often. Therefore, Mapwel converts all input data like shape files or calibration point coordinates to WGS84 angular coordinates, which are used in its internal data structures. UTM zones are numbered consecutively beginning with Zone 1, which includes the westernmost point of Alaska, and progress eastward to Zone 19, which includes Maine. Map files compatible with Garmin GPS units use WGS84 too. Most UTM users and GPS (Global Positioning System) units use the full value of the UTM coordinates. The UTM (Universal Transverse Mercator) coordinate system divides the world into sixty north-south zones, each 6 degrees of longitude wide. The military implementation of UTM (Military Grid Reference System or MGRS) drops the small digits and indicates the 100,000 meter square by a two letter identifier. The millions and hundreds of thousands of meters are shown with small numbers and are sometimes dropped when giving UTM coordinate positions. Note that the large numbers adjacent to the tick marks around the perimeter of the map represent tens of thousands and thousands of meters. Measurements can be made using a gridded mylar overlay, a paper scale, or a coordinate reader. ![]() This narrows down the coordinate to a 100 meter or 10 meter square. To make UTM measurements, subdivide the 1,000-meter grid squares into tenths or hundredths. Some maps, including all those produced after 2009 ( US Topo maps) include full UTM grid lines. US Topo map showing latitude and longitude of the corner (38°N, -115.8750°W) and brown UTM gridlines (4,206,000 meters northing and 599,000 meters easting)Īlmost all USGS topographic maps produced after 1977 show UTM tick marks on the sides of the map (or a full-line grid) every 1,000 meters.
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