Appendix: Glossary
95
Leg
One portion of a route, consisting of starting and destination
waypoints.
Longitude
Position east or west of the prime meridian, measured in degrees.
Man
Manual
MPH
Miles per hour
National Marine
Electronics Association
(NMEA)
A US standards committee that defines electrical and data
specifications for communications between marine electronics.
NMEA standards provide protocols by which marine instruments
and also most GPS receivers can communicate with each other.
nm
Nautical Mile
NMEA
National Marine Electronics Association
North Up Orientation
Displays the chart orientation with true north upwards. As your
heading changes the boat symbol moves accordingly. This is the
default mode for the chart application.
Paddlewheel Speed
See ‘Boat Speed’
Range
Distance to the specified waypoint.
Route
A sequential series of waypoints entered into the chartplotter that
direct the boat to the desired destination.
RTE
Route
s
seconds
sm
Statute Miles
SOG
Speed Over Ground
Speed Over Ground
(SOG)
The actual speed the boat is moving, as measured by the GPS. This
measurement differs from paddlewheel speed, which does not take
into account current, wind or other sea conditions.
Time To Go (TTG)
Estimated time that will elapse before reaching waypoint, at the
current course and speed.
Time Variable Gain
(TVG)
A DSM gain setting that reduces clutter by varying the gain
throughout the water column This function is useful for reducing the
appearance of ‘noise’.
TTG
Time To Go
TVG
Time Variable Gain
