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Purpose of the Blue Arrow on the Course Deviation Indicator

The Course Deviation Indicator (CDI) provides a graphic indication of drift (right or left) and displays the distance off course.

The blue arrow on the CDI page is called the To/From indicator. It is an indication as to where your destination is in relationship to you; either ahead or behind. If your destination is in front of you it will point forward. If your destination is behind you it will point backwards. This can cause the arrow to flip 180 degrees.

Using the CDI can help you stay on course and avoid drifting away from your destination.

Using the Course Deviation Indicator

NOTE: To enable the course pointer from the compass page, see your device's owner's manual

Once the CDI is enabled, you need to use the Go command to navigate an item. While navigating, you will see different lines on the Map and Compass pages to help you stay on course (see below for examples). 

When using the Course Pointer, and the device drifts away from the line of travel to the destination (course line), the Course Deviation Indicator (CDI) provides graphic indication of drift (right or left) and displays the distance off course.

When a device has deviated from its course, the center of the arrow will separate from the pointer, moving right or left. The arrow always points to the determined course. It is important to understand that once a destination is activated and a course line is generated, the course never changes, regardless of the device's current location. The portion separated from the pointer (the bar) indicates the distance the device is from the actual course line.

If the bar is aligned in the center, the device is on the desired course. If the bar deviates right or left, the device is off course.


Map Page

Thinner Pink Course Deviation Line and Thicker Pink Navigation Line Shown on the Map Page 


Compass Page

To aid in navigation, there are dots in the center of the compass on either side of the course arrow (see example 4 below); each dot represents a distance (0.25mi by default but can be adjusted). If the CDI scale is set to 0.25mi and the device is 0.50mi off course, then the bar will be deflected 2 dots. Use the Zoom buttons to adjust the CDI scale setting.

Course Deviation Line on Compass 

The course pointer Blue Number 1 in a Blue Circle indicates your relationship to the course line leading to the destination. The course deviation indicator (CDI) Blue Number 2 in a Blue Circle provides the indication of drift (right or left) from the course. The scale Blue Number 3 in a Blue Circle refers to the distance between dots Blue Number 4 in a Blue Circle on the course deviation indicator, which tell you how far off course you are.