Magellan Trailblazer XL Reference Manual page 58

Specifically, a location is so many
degrees north or south of the
equator (up to the poles, which are
90°N and 90°S; the equator is 0°
latitude), and so many degrees
east or west of the Prime Merid-
ian, which is 0° longitude. (The
Prime Meridian passes through
Greenwich, England.) Parts of a
degree are minutes; there are 60
minutes (written as 60') to a de-
gree. Minutes can also be divided
into smaller units. Fractions of a
minute can be expressed as deci-
mals or as seconds. (There are 60
seconds to one minute, written as 60"). So a Lat/Lon position coordinate can be ex-
pressed in two ways, which your Magellan GPS receiver displays as 25°47.50 or
25°47'30.
UTM Coordinate System
Another commonly used coordinate system is UTM (Universal Transverse Mercator),
which is generally found on land-based maps and quad sheets that are produced by
government map providers. On land, you may find that UTM coordinates are easier to
use than Lat/Lon.
UTM coordinates are easy to use, but since the model it is based on is somewhat
abstract, this section is a very simplified introduction to UTM.
Instead of projecting an imaginary grid of intersecting lines onto the globe, UTM projects
sections of the globe onto a flat surface. Each of these sections is called a "zone."
There are 60 zones to cover the entire earth between 84°N and 80°S (polar areas are
not described by UTM). Each zone is 6° wide as projected from the earth's center.
A UTM location is described by three elements; the zone it is in, the easting, and the
northing. Eastings and northings measure how far into a zone a position is in meters.
Eastings are an east/west measurement, and correspond roughly to longitude. Northings
are a north/south measurement, and correspond to latitude.
This chart shows the location of Magellan Systems described in both Lat/Lon and UTM
coordinates.
DEG/MIN
34°06.58N
117°49.56W
GPS Navigation
LAT/LON
DEG/MIN/SEC
34°06'35"N
117°49'34"W
UTM
11 4 23 818 E
37 74 624 N
49