Garmin 695 Manuale Utente

Pagina di 280
Garmin GPSMAP 695/696 Owner’s Manual
190-00919-00 Rev. G
Appendix H
247
Overview
GPS Navigation
Flight Planning
Hazar
d A
voidance
Additional F
eatur
es
Appendices
Index
MAP DATUM AND LOCATION FORMATS
MAP DATUMS
A datum is a mathematical model of the Earth that approximates the shape of the 
Earth and enables calculations to be carried out in a consistent and accurate manner. 
The datum is physically represented by a framework of ground monuments (such as 
trig. stations) whose locations have been accurately measured and calculated on this 
reference surface.  Lines of latitude and longitude on a chart are referenced to a specific 
map datum.  Every chart has a map datum reference and the GPSMAP 695/696 can be 
set to match most of those commonly used.
LOCATION FORMATS
Your current location can be viewed on the GPS in the form of coordinates.  Since 
different charts use different location formats, Garmin GPS units allow you to choose 
the correct coordinate system for the type of chart you are using.  The most common 
format is latitude and longitude, which is used by all Garmin units.  You can change the 
location format to use with other coordinate systems.  Several other grids, including a 
user-definable grid (for the advanced user), are available.