Military Grid Reference System

The Military Grid Reference System (MGRS) is the geographic standard used by NATO militaries for locating any point on the earth with a 2 to 10 character geocode. A two digit code implies a precision of 10 km and a ten digit code corresponds to a 1 m precision with intermediate steps of 1 km, 100 m, and 10 m. It is always displayed in an even number of characters preceded by an alpha-numeric code describing the larger Earth area to which it belongs.

For instance, 38 S MC12345678 would be read as:

Section: 38

Sub Section: S

Map Section: MC

Map Point: 12345678

The map point is broken down further into to equally sized parts of 1, 2, 3, 4 or 5 digits. In this example it would be 1234 and 5678.

As with other mapping standards, one reads the map point from West to East first (Easting), then from South to North (Northing). So 1234 would be the longitudinal equivalent and 5678 would be the latitudinal equivalent.

The Military Grid Reference System is based on the Universal Transverse Mercator mapping system between latitudes 80°S and 84°N; in the polar regions it is based on the Universal Polar Stereographic projection.

Reference

• Datums, Ellipsoids, Grids, and Grid Reference Systems, DMA Technical Manual 8358.1, U.S. National Geospatial-Intelligence Agency.
• U.S. Army Field Manual 3-25.26 on Global Security

External links

• A list of coordinate systems - by Prof. Peter H. Dana at the Univ. of Colorado
• GEOTRANS Geographic Translator software and source code from the US National Geospatial-Intelligence Agency

See also

There are other geographic naming systems of this alphanumeric kind:

• An alternative system called the Global Area Reference System has been proposed by the National Geospatial-Intelligence Agency for use across the Department of Defense.

• The Georef system has been used for air navigation, but is rarely seen today.

• The Maidenhead Locator System is used by amateur radio operators.

• A modification of the Military Grid Reference System is used by the Atlas Florae Europaeae for mapping the distribution of vascular plants in Europe.