Raymarine A Series A50 User's Reference Manual page 50

Range rings
Range rings are a series of concentric circles a set distance apart.
They are used to help assess the distance between objects on the
chart.
To switch range rings on or off
1. Press the PRESENTATION softkey.
2. Press CHART LAYERS AND DATA softkey.
3. Press CHART LAYERS.
4. Use the TRACKPAD to select the RANGE RINGS layer and turn
them on or off as required.
5. Press OK to save your settings.
50
Ruler
The chart application includes a ruler which accurately measures
the distance and bearing between two points.
To use the ruler
1. Position the cursor at the start-point of the measured distance.
2. Press the PRESENTATION softkey.
3. Press CHART LAYERS AND DATA softkey.
4. Press the RULER softkey.
5. Move the cursor to the end-point of the measured distance.
6. Press OK.
To move the ruler
1. To move the start-point, press ADJUST A.
2. To move the end-point, press ADJUST B.
To clear the ruler
1. Press CLEAR RULER.
B
A
o
008 T
0.46nm
A-Series display - User reference manual