User manual - JG Technologies

D12214-1
D12215-1
D12216-1
12.11 Using radar to measure distances,
ranges, and bearings
When you are using the radar application, you can measure
distances, ranges and bearings in a variety of ways.
These options are detailed in the table below:
Functions
Range Rings
Distances
Between Points
Yes
(approximate
distance)
Range From
Your Vessel
Yes
(approximate
range)
Cursor No Yes Yes
Variable Range
Markers /
Electronic
Bearing Lines
(VRM/EBL)
Bearings
No
No Yes Yes
A Variable Range Marker (VRM) is a circle centred on your vessel’s
position and fixed with respect to the heading mode. When this
circle is adjusted to align with a target, its range from your vessel
is measured and displayed on the Radar context menu when you
select the VRM with the cursor.
Electronic Bearing Lines (EBL)
An Electronic Bearing Line (EBL) is a line drawn from your vessel
to the edge of the window. When this line is rotated to align with a
target, its bearing relative to your vessel’s heading is measured and
displayed on the Radar context menu when you select the VRM
with the cursor.
The VRM/EBL are combined to measure both the range and the
bearing of the specified target.
1 2 3
4
0.624nm
56°S
Floating
VRM/EBL
Yes No Yes
VRM/EBL
Measuring using the range rings
Use the range rings to gauge the approximate distances between
points. Range rings are concentric circles displayed on the screen
and centred from your vessel at pre-set distances. The number and
spacing of the rings changes as you range in and out.
Examples:
D8403-2
Item
Description
1 VRM
2 Target
Range — 1/4 nm
Range Rings — 760ft
apart
Range — 3/4 nm
Range Rings — 1/4 nm
apart
Range — 1 1/2 nm
Range Rings — 1/4 nm
apart
3 EBL
4 Range and bearing
Measuring using the cursor
To measure the bearing and range from your vessel to a specified
target, move the cursor to the appropriate position on the screen
and press Ok, the radar context menu will be displayed which shall
provide:
• Latitude
• Longitude
• Range
• Bearing
1 2
Measuring using floating VRM/EBL
You can use the VRM/EBL float function to measure the range and
bearing between any two points on the radar screen. This function
allows you to move the VRM/EBL centre away from your vessel’s
position and onto a target. You can then change the radius of the
VRM to determine the distance between two points and change the
angle of the EBL, relative to its new origin, to obtain the bearing.
1
0.471nm
55°P
2 3
VRM/EBL
D12218-1
Item
Description
1. Cursor
D12217-1
2. Bearing and range from your vessel to
the cursor position
Item
Description
1 Range and bearing
2 Target 1
3 Target 2
You can also display the cursor position in the databar, from the
homescreen select: Customize > Databar Set-up > Edit Databar,
now select the data box where you want the cursor position to be
displayed. Select Navigation > Cursor Position.
Measuring using VRM/EBL
Variable Range Markers (VRM)
138 e7 / e7D / e95 / e97 / e125 / e127 / c95 / c97 / c125 / c127