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Owner's Manual
horizontal direction of one terrestrial point from another referring to the
North (True or Magnetic). It is often used to indicate the direction to follow
to reach the destination.
Chain (Loran-C GRI)
The Loran chains are groups of transmitting stations that use timed radio
pulse transmissions. In each of these chains there is a master station and
two or more slave or secondary stations. Stations belonging to a same
chain transmit pulses in timing groups: a different time base identifies each
chain. The time base of each chain is the Group Repetition Interval or GRI.
This GRI identifies the chain in unique mode. For example the GRI = 4990
identifies the chain of Central Pacific zone.
COG = Course Over Ground
Direction of the path over ground actually followed by a vessel.
Course Line (Time Line)
The Course Line is a graphical indication of the direction in which the
Vessel is heading. The Course Line origin is the vessel’s position so the
time line movement is synchronized with the vessels Icon. Course Line
"course" is given by the value of COG (Course Over Ground) and its length
is proportional to the SOG (Speed Over Ground).
CTS = Course To Steer
The optimum direction the boat should be steered in order to efficiently
make headway back to the courseline while also proceeding toward the
destination Waypoint.
Cultural Features
Any man-made topographic feature as built-up area, buildings, roads.
Datum
The Latitude and Longitude lines printed on any map are based on certain
models of the shape of the earth: these models are called Datum or
Coordinate Systems. There are many different Datum in use, each one
gives different Lat/Lon positions for an identical point on the surface of the
earth (see also Map Datum and Fix Datum).
Dead Reckoning
It is the procedure to determine the current position of a vessel by applying
to the last known position the way that has been made (since the last
known position was received). This procedure is normally based on the last
received GPS position, Speed and Course or to the last received GPS
position, Log Speed and Heading.
Default
Indicates the original factory setting for any menu selection. The default
values are set after a Master Reset (RAM Clear).
Terms