Garmin GPS 150 - Manual (Page 70)

The GPS 150 contains over 100 map datums for you to use when navigating with
the GPS 150. By default, your GPS 150 calculates positions using the WGS-84 map
datum. If you are using charts based on another datum, you must set the GPS 150 to
use that datum if you are using the coordinates provided on that chart. Using the
WGS-84 datum on the GPS 150 while using a different datum for maps or other navi-
gation devices could result in significant differences in position information.
If you are using maps for reference only, the GPS 150 will provide correct
navigation guidance to the waypoints contained in the database regardless of the
datum selected.
To change the map datum to one listed in Appendix E:
1. Press
S
and rotate
O
until the Map Datum page is displayed.
2. Press
C
to highlight the current map datum.
3. Rotate
K
to change the datum.
4. Press
C
to complete.
To create a user datum:
1. Press
S
and rotate
O
until the Map Datum page is displayed.
2. Press
C
and rotate
O
to highlight ‘Define user datum?’. Press
E
.
3. Enter the 5 parameters of the map datum using
K
and
O
. Press
E
to accept a field.
The sign of each value (+/-) should follow the convention: WGS84-local geodetic system.
4. Rotate
O
to highlight ‘ok?’ and press
E
.
5. To activate the user datum, select ‘USER’ on the map datum page as described above.
60
REFERENCE
Map Datums
Section
5
User Datum page
Map Datum page
Map Datum page with ‘User’ selected.
150man rev E 7/24/98 3:10 PM Page 60