Magellan iCGRS User Manual page 77

People hiking or walking would normally see the heading and COG being the same with
the SporTrak Color pointing directly ahead. However, with the receiver held at a slight
angle, left or right, you can see that the heading displayed will differ from the displayed
COG.
The key point to remember is while you are moving, COG is the true indication of your
direction of travel. COG is displayed only while you are moving at a computed speed of
0.5 miles or faster.
Bearing
Bearing is simply the direction you need to travel to arrive at
your destination.
Using the same diagram as before, a destination to a fishing
spot has been added. The bearing displayed then indicates
the direction that you would need to travel to arrive at the
fishing spot.
Bearing will be displayed only when you have a GOTO or
other route active.
Putting it All Together
With bearing and COG computed, the SporTrak Color can now provide you with the
precise information you need to arrive at your destination in the shortest time. In the
above example the SporTrak Color would compute that you need to turn 65 to get to
your fishing spot. (Remember, since COG is your true heading, the angle you need to
turn is the difference between COG and bearing, not heading and bearing.)
As soon as you make this turn, the force of the current on your boat would change. This
would also change how much difference there is between your heading and COG. The
SporTrak Color continually updates this information giving you the exact turn informa-
tion you will need to arrive at your destination.
Always remember:
• Heading is the direction that the SporTrak Color is pointing and is displayed all
the time.
• Course Over Ground (COG) is the direction that you are travelling over the
ground. COG is displayed only while you are moving.
• Bearing is the direction to the destination of a GOTO or leg of a route. Bearing is
displayed only when a GOTO or route is active.
SporTrak Color GPS Mapping Receiver
Appendix
Heading
COG
0
Bearing
15
310
69