Geodetic::Coordinate::MGRS - Military Grid Reference System¶

Overview¶

MGRS (Military Grid Reference System) is a geocoordinate standard used by NATO militaries for locating points on Earth. It is based on the UTM coordinate system, augmented with a lettering scheme for grid zone designators and 100km square identifiers.

Constructor¶

From a complete MGRS string¶

MGRS.new(mgrs_string: "18SUJ2337006519")

From individual components¶

MGRS.new(
  grid_zone:  "18S",
  square_id:  "UJ",
  easting:    23370,
  northing:   06519,
  precision:  5
)

String Representation¶

Method	Description
`from_string`	Parses an MGRS string into its components
`to_s`	Returns the compact MGRS string representation

Example¶

mgrs = Geodetic::Coordinate::MGRS.new(mgrs_string: "18SUJ2337006519")
mgrs.to_s  # => "18SUJ2337006519"

Precision Levels¶

MGRS supports five levels of precision, controlling the number of digits in the easting and northing components:

Precision	Digits (per axis)	Resolution
1	1	10 km
2	2	1 km
3	3	100 m
4	4	10 m
5	5	1 m

Components¶

Component	Description	Example
`grid_zone`	UTM zone number + latitude band letter	`18S`
`square_id`	100km square identification (two-letter code)	`UJ`
`easting`	Easting within the 100km square	`23370`
`northing`	Northing within the 100km square	`06519`
`precision`	Number of digits per coordinate (1-5)	`5`

Conversions¶

MGRS converts to other coordinate systems via UTM and LLA:

MGRS -> UTM — Decomposes the grid zone and square ID back to UTM easting/northing.
MGRS -> LLA — Converts through UTM to latitude/longitude.

Example¶

mgrs = Geodetic::Coordinate::MGRS.new(mgrs_string: "18SUJ2337006519")

mgrs.grid_zone  # => "18S"
mgrs.square_id  # => "UJ"
mgrs.easting    # => 23370
mgrs.northing   # => 06519
mgrs.precision  # => 5
mgrs.to_s       # => "18SUJ2337006519"