MGRS

MGRS stands for Military Grid Reference System. It is a geocoordinate system used by NATO militaries and allied organizations to express location in a compact, unambiguous form. It is built on the same underlying projections as the Universal Transverse Mercator (UTM) coordinate system and the Universal Polar Stereographic (UPS) system for polar areas. MGRS coordinates associate a location with a zone, a 100,000-meter square, and a pair of easting and northing values within that square, enabling precise reporting without decimal coordinates.

In practice, an MGRS string consists of the zone number (01–60), a latitude band letter (C–X, excluding I and O), a two-letter 100km square designator, and an even-length sequence of digits giving the easting and northing within that square. More digits means finer precision; common forms provide roughly sub-kilometer to meter-level accuracy depending on digits. For example, an illustrative form might look like "33S QF 1234 5678" (with digits shortened or extended as needed). Note this is illustrative; actual valid 100km-square letters depend on the zone.

MGRS is widely used for military map reading, navigation, and field operations because it is compact and can be transmitted quickly, especially via voice radio without mishearing long coordinates. It is also supported in most GIS software and mapping devices, which can convert between MGRS, latitude/longitude, and UTM.