Navigation Setup Page
The navigation setup page is used to select the
desired position format, map datum, CDI scale, units of
measure for speed and distance, and a heading reference.
Navigation Setup: Position Formats
The default position format for the GPS 12 is lati-
tude and longitude in degrees and minutes (hdddº
mm.mmm’). You may also select degrees, minutes and
seconds (hdddºmm’ss.s’’); degrees only (hddd.dddddº);
UTM/UPS; MGRS; Maidenhead; User-defined Grid; or
regional British, German, Irish, Indonesian, Indian,
Swedish, Swiss, Taiwan, or West Malayan grids.
To select a position format:
1. Highlight the ‘POSITION FRMT’ field, and press
E
.
2. Select the desired setting, and press
E
.
Navigation Setup: User Grid Position Format
The ‘User Grid’ option lets you create a user-defined
position format by establishing factors such as longitude
of origin, scale, and false Easting or Northing.
To define a user grid:
1. Select ‘User Grid’, and press
E
.
2. Enter values for longitude origin, scale, and false
Easting and Northing, and press
E
.
3. Highlight ‘SAVE?’, and press
E
.
Navigation Setup: Map Datums
The ‘MAP DATUM’ field comes with a ‘WGS 84’
default setting. Although over 100 map datums are
available for use (see Appendix D for map datums), you
should only change the datum if you are using maps or
charts that specify a different datum than WGS 84. If no
datum is specified, you may select each datum applica-
ble to your region until you find the datum that pro-
vides the best positioning at a known point.
To select a map datum:
1. Highlight the ‘MAP DATUM’ field, and press
E
.
2. Select the desired setting, and press
E
.
Warning: Selecting the wrong map datum can result
in substantial position errors. When in doubt, use the
default WGS 84 datum for best overall performance.
Navigation
Setup
REFERENCE
44
The position format may
be set to display your
choice of many formats.
Note: degree and minutes
is the default setting.
The default map datum
covers world-wide naviga-
tion. However, if you are
using a paper map or
chart which uses a differ-
ent map datum that WGS
84, then you may wish to
switch to that datum to
make your GPS 12 posi-
tion readout correspond to
the chart.
GPS12B 1/13/99 4:28 PM Page 44
