Map Datums; Units Of Measure - Garmin 128 Owner's Manual

REFERENCE
Datums, CDI
Settings, &
Measurement
The default map datum
will cover worldwide nav-
igation. However, if you
are using a paper map or
chart which uses a differ-
ent map datum than WGS
84, then you may wish to
switch to that datum.
The user datum feature
allows you to define the
earth model used to calcu-
late position coordinates.
WARNING: Incorrect
entries may result in sub-
stantial position errors.
48
User Grid Option
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
longitude origin, scale, false Easting and Northing,
F
then press

Map Datums

The 'datum' field is located just below the 'position'
field and comes with a WGS 84 default setting.
Although 106 total 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.
To select a map datum:
1. Highlight the 'datum' field, and press
2. Select the desired setting, and press
To define a user datum:
1. Highlight the 'datum' field, and press
2. Scroll through the map datum options until 'User'
appears, and press
3. Enter values for 'DX', 'DY', 'DZ', 'DA', and 'DF' using the
rocker keypad, and press
4. Highlight 'SAVE?', and press
will reappear.
CDI Scale Settings
The course deviation indicator (CDI) field lets you
select the +/- range of the CDI bar scale on the Highway
Page. Three scales are available: +/- 0.25 (default), 1.25,
and 5.0 miles or kilometers. Note: This CDI value rep-
resents the full deflection of scale to either side.
To enter a CDI scale setting:
1. Highlight the 'cdi scale' field, and press
2. Select the desired setting, and press

Units of Measure

The GPS 126/128 lets you select statute (default),
nautical, or metric units of measure for all 'speed' and
'distance' fields.
F
. Enter values for
. Highlight 'SAVE?', and press
F
F
F
F
.
F
.
F
. The setup menu
F
F
.
.
.
.
F
.
.