There is nothing mysterious about the UTM coordinate system. Its basis is that a meter is 1/10,000,000th of the distance between the Equator and the Poles (assuming that the Earth is a perfect sphere, and we'll not get into geodetic quibbling about the fact that the Earth is actually an oblate spheroid).
If we imagine the Earth as having longitudinal zones (slices, like an orange) of 6� apiece, and then apply the meter distance consistently in both northward and eastward directions within any zone, it becomes easy to specify any location very precisely. We begin counting meters at the Equator and at the western longitude of each zone. Eastern Wisconsin, for example, falls into UTM Zone 16, between 84�W and 90�W longitude.
The only complications in the whole scheme are that "northings" begin at the Equator for the northern hemisphere but at the South Pole for the southern hemisphere, and that (because of longitudinal convergence at latitudes greater than 80�) UTM requires a special grid in the high polar regions. Either circumstance appears unlikely to affect us.
Latitude has bands in 8 degree increments, and labeled with letters (military grid, which is what some of our software uses). All of Wisconsin falls into latitude band "T". Eastern Wisconsin therefore is in the UTM sector of 16T.
The convention for communicating UTM coordinates is a shorthand scheme for truncating eastings and northings to a desirable quadrat resolution. A full (and rather cumbersome) UTM coordinate specification for a location on campus might look like:
16 T 0296190 4930797 (meaning Zone 16 T; 296,190 meters east; and 4,930,797 meters north)
Since most ground search parties confine their efforts to fairly small (sometimes downright tiny) areas, we can abbreviate the UTM coordinates to four-, six-, eight-, or ten-digit specifications by dropping the zone information and the unnecessary digits for millions and hundred thousands of meters. This facilitates faster note-taking and radio communications, but still enables accurate point specification to a desirable area resolution. The area resolutions for the campus location above would be:
| four digit: | 96/30 | (to the nearest 1000 meters, or kilometer) |
| six digit: | 961/307 | (to the nearest 100 meters, or hectometer) |
| eight digit: | 9619/3079 | (to the nearest 10 meters, or decameter) |
| ten digit: | 96190/30797 | (to the nearest 1 meter) |
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