: Doug,

: I think you are one place off. If I remember correctly UTM (Universal
: Transverse Mercator) and MGRS (Military Grid Reference System) are very
: similar. MGRS divides the globe into 10km grids. People refer to 6,8, and
: 10 digit MGRS which define 100m, 10m, and 1m squares respectively. In
: other words, 10 digits gives you 5 each for 'northing' and 'easting'. I
: think 0,0 would be the south west corner of a grid. This one I forget
: sometimes. Anyway, my GPS (Garmin 12) provides MGRS in 10 digits as an
: option. When I was testing the other night my estimated position error
: (EPE) was displayed as 17'. I switched to MGRS and the last position
: varied by no more than 4 (4 meters) for several minutes. This agrees
: fairly well with a 17' EPE.

: Tim

Correction, MGRS is based on 100km grids. (duh, 5 digits would give you up to 99,999 meters, or the south west corner of the north east most 1 meter square on a 100km grid). A little more digging, the common reference between UTM and MGRS seems to end with the UTM zone number and letter. For example 16 S (My zone here in Atlanta).