Geodetic::Coordinate::USNG - US National Grid¶

Overview¶

USNG (US National Grid) is a coordinate system based on MGRS, adopted for use by US emergency services and civilian agencies. It provides a consistent, interoperable grid reference system across the United States.

Constructor¶

From a complete USNG string¶

USNG.new(usng_string: "18T WL 12345 67890")

From individual components¶

USNG.new(
  grid_zone:  "18T",
  square_id:  "WL",
  easting:    12345,
  northing:   67890,
  precision:  5
)

Format Differences from MGRS¶

USNG uses a spaced format for readability, whereas MGRS uses a compact (unspaced) format:

System	Format
USNG	`18T WL 12345 67890`
MGRS	`18TWL1234567890`

String Representation¶

Method	Description
`from_string`	Parses a USNG string into its components
`to_s`	Returns the USNG string representation
`to_full_format`	Returns the full spaced USNG format
`to_abbreviated_format`	Returns an abbreviated representation

Validation¶

Method	Description
`valid?`	Checks that the zone designator falls within valid US zones

Conversions¶

USNG converts through MGRS internally. All coordinate conversions follow the chain:

USNG <-> MGRS <-> UTM <-> LLA

Example¶

usng = Geodetic::Coordinate::USNG.new(usng_string: "18T WL 12345 67890")

usng.grid_zone  # => "18T"
usng.square_id  # => "WL"
usng.easting    # => 12345
usng.northing   # => 67890
usng.precision  # => 5

usng.to_s                  # => "18T WL 12345 67890"
usng.to_full_format        # => Full spaced format
usng.to_abbreviated_format # => Abbreviated format
usng.valid?                # => true (if within valid US zones)