The map is displayed by GISsurfer which is a general purpose map based on the Apple map. For a description of all the features of GISsurfer that support MGRS coordinates (search, geolocation, etc) USNG stands for U.S. National Grid. MGRS and USNG are the same except MGRS is often written without spaces. If you know MGRS then you already know USNG. The purpose of this field manual is to provide a standardized source document for Armywide reference on map reading and land navigation. This…