U.S. National Grid Conversion


The national grid will improve public safety, commerce, and aid the casual GPS user with an easy to use
geoaddress system for identifying and determining location with the help of a USNG gridded map and/or a USNG
enabled GPS system. Although the USNG can provide for what ever level of precision desired, users may prefer to
use the UTM format for applications requiring precision greater than 1 meter.

Grid Zone Designation. The U.S. geographic area is divided into 6-degree longitudinal zones designated by a
number and 8-degree latitudinal bands designated by a letter. Each area is given a unique alpha-numeric Grid Zone
Designator (GZD) (i.e. 18S).

100,000-meter Square Identification. Each GZD 6x8 degree area is covered by a specific scheme of 100,000-meter
squares where each square is identified by two unique letters. (i.e. 18SUJ - Identifies a specific 100,000-meter
square in the specified GZD).

Grid Coordinates A point position within the 100,000-meter square shall be given by the UTM grid coordinates in
terms of its Easting (E) and Northing (N). An equal number of digits shall be used for E and N where the number
of digits depends on the precision desired in position referencing. In this convention, the reading shall be from
left with Easting first and then Northing. 

        Examples:



        18SUJ20 - Locates a point with a precision of 10 km



        18SUJ2306 - Locates a point with a precision of 1 km 



        18SUJ234064 - Locates a point with a precision of 100 meters



        18SUJ23480647 - Locates a point with a precision of 10 meters 



        18SUJ2348306479 - Locates a point with a precision of 1 meter 



        The number of digits in Easting and Northing can be varied, depending on specific requirements or

        application.