Garmin GPS 165 TSO - Manual (Page 103)

The GPS 155 contains over 100 map datums for you to use when navigating. By
default, your unit calculates positions using the WGS-84 map datum. If you are using
charts based on another datum, you must set the GPS 155 to use the same datum.
Using a map datum that does not match the sectionals you are using can result in sig-
nificant differences in position information. If you are using maps for reference only,
the GPS 155 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 use O to display the ‘Map datum’ page.
2. Press C .
3. Use
O
to highlight the current map datum.
4. Use K to change the datum.
5. Press C to complete.
To create a user datum:
1. Press
S
and use
O
to display the ‘Map datum’ page.
2. Press C .
3. Use
O
to highlight ‘Define user datum?’. Press
E
.
4. Enter the 5 parameters of the map datum using K and O . Press E to accept a field.
The signs of each value (+/-) should follow the convention: WGS84-local geodetic system.
5. Use O to highlight ‘ok?’ and press E .
6. To activate the user datum, select ‘USER’ on the map datum page as described above.
93
UNIT SETTINGS
Using Map Datums
Defining user map datum.
Map Datum Page.
155man (GOOD) 7/24/98 1:57 PM Page 93