Military Grid Reference System (MGRS)

The Military Grid Reference System (MGRS) is a two-dimensional grid that uniquely identifies a square meter anywhere on the earth. The MGRS attempts to represent the entire surface of the Earth on a worldwide grid. The grid is based on the UTM (between 80°S and 84°N latitudes) and UPS (Universal Polar Stereographic) systems.

Currently, the Geographic Calculator only supports MGRS points in the UTM-based latitude range (between 80°S and 84°N ).

MGRS coordinates are comprised of 7 parts, 3 of which correspond to the UTM/UPS zone that contains the coordinate. In addition to the Datum (which is not explicitly expressed in the MGRS coordinate), the UTM/UPS zone and latitude band (described below) are part of the MGRS point.

UTM

MGRS Coordinates

The MGRS coordinate consists of seven parameters:

  1. Datum (as applied to MGRS)

    Equivalent to corresponding UTM/UPS datum, and thus is not expressed explicitly in the coordinate.

  2. Zone Number

    Equivalent to corresponding UTM/UPS zone number.

    Example:
    19TDJ3858897366

    19” is equivalent to the corresponding UTM zone.

  3. Band Letter

    Equivalent to UTM/UPS latitude band letter.

    Example:
    19TDJ3858897366

    T” is the corresponding UTM latitude band letter.

  4. MGRS Column Letter

    This is the first of 2 letters used to define the 100 kilometer square within the UTM/UPS block. The columns A-Z (excluding "I" and "O"), like UTM, start at 180° and increase toward the East. Every 3 columns, the pattern repeats.

    Example:
    19TDJ3858897366

    D” is the MGRS column letter

  5. MGRS Row Letters

    This is the second of 2 letters used to define the 100 kilometer square within the UTM/UPS block. Row letters increase to the North. The letters cycle backwards through the alphabet in the southern hemisphere (J, H, G, ... going south).Zone 1, A-H; Rows

  6. MGRS Easting

    MGRS Easting value consists of 5 digits. Represents the number of meters east of the origin (i.e. southwest corner) of the 100 kilometer square in which it is contained.

    Example:
    19TDJ
    3858897366

    38588is the MGRS Easting value

  7. MGRS Northing

    MGRS Northing value consists of 5-digits. Represents the number of meters north of the origin (i.e. southwest corner) of the 100 kilometer square in which it is contained.

    Example:
    19TDJ3858897366

    97366” is the MGRS Easting value

 

Example MGRS Coordinate Conversion

44° 13’ 36.96” N, 069° 46’ 08.11” W (Geodetic/WGS84) is equivalent to 19TDJ3858897366MGRS(WGS84).

UTM Zone 19

Latitude Band T

MGRS column D

MGRS row J

MGRS Easting 38588

MGRS Northing 97366

Note the DATUM is not explicitly stated in the MGRS coordinate.

Conversions between geodetic and MGRS are ellipsoid dependent.

References:

Parker, W. and Bartholomew, R., Issues in Automating the Military Grid Reference System, IN: The Fifth International Geodetic Symposium on Satellite Positioning, Vol. II, 903-913.

Parker, W.S., and Bartholomew, R.G., 1988, Mapping, Charting, and Geodesy in the DoD Standard GPS Receivers, IEEE Plans Record, 145-152.

NOTE: This coordinate system is not supported for vector data conversions