addr:LocationUSNG_type

The USNG or US National Grid is an alphanumeric
reference system that overlays the Universal Transverse
Mercator (UTM) numerical coordinate system. A USNG
coordinate consists of three parts, the: 1. Grid Zone
Designation (GZD) for worldwide unique geoaddresses (two
digits plus one letter, developed from the UTM system).
2. 100,000-meter Square Identification for regional
areas (two letters). 3. Grid Coordinates for local areas
(always an even number of digits between 2 and 10
depending upon precision necesary to uniquely identify
the location). Look to
www.fgdc.gov/standards/status/usng.html for a normative
definition.