Garmin 531 Manuale Utente

Viewing Information 

The location of this symbol indicates the closest point of 

approach to a dangerous target, and the numbers near the 

symbol indicate the time to the closest point of approach 

to that target. 
Dangerous target is lost. A red 

X indicates that the AIS 

transmission from the vessel is lost, and the chartplotter 

displays a message banner asking whether the vessel 

should continue to be tracked. If you discontinue vessel 

tracking, the lost dangerous target symbol disappears from 

the chart or the 3D chart view. 

When course over ground and heading information are provided by 

an activated AIS target, the heading of the target appears on a chart 

as a solid line attached to the AIS target symbol. A heading line does 

not appear on a 3D chart view.
The projected course of an activated AIS target appears as a dashed 

line on a chart or a 3D chart view. The length of the projected course 

If an activated AIS target is not transmitting speed information, or 

if the vessel is not moving, a projected course line does not appear. 

Changes in the speed, the course over ground, or the rate-of-turn 

information transmitted by the vessel can impact the calculation of 

the projected course line.

When course over ground, heading, and rate-of-turn information 

are provided by an activated AIS target, the projected course of the 

target is calculated based on the course over ground and the rate-of-

turn information. The direction in which the target is turning, which 

is also based on the rate-of-turn information, is indicated by the 

direction of the barb at the end of the heading line. The length of the 

barb does not change.