Bearings
Introduction
Introduction
A bearing is the angle of a direction measured in a clockwise direction from the North. The bearing is typically given as a 3-digit number from 000° to 359° to an accuracy of typically 1 decimal place.
A bearing is the angle of a direction measured in a clockwise direction from the North. The bearing is typically given as a 3-digit number from 000° to 359° to an accuracy of typically 1 decimal place.
In the applet on the right, you can move the Blue Point B around and see how the location of Point B from Point A is given using a distance and a direction (in the form of a bearing).
In the applet on the right, you can move the Blue Point B around and see how the location of Point B from Point A is given using a distance and a direction (in the form of a bearing).
Cardinal Directions
Cardinal Directions
The 4 cardinal directions are:
The 4 cardinal directions are:
- North (N) at 000° bearing;
- East (E) at 090° bearing;
- South (S) at 180° bearing; and
- West (W) at 270° bearing.
In addition, 4 ordinal directions are defined as the angle bisectors of adjacent cardinal directions. They are:
In addition, 4 ordinal directions are defined as the angle bisectors of adjacent cardinal directions. They are:
- North-East (NE) at 045° bearing;
- South-East (SE) at 135° bearing;
- South-West (SW) at 225° bearing; and
- North-West (NW) at 315° bearing;
Video Summary
Video Summary
This youtube video is a summary of the concepts of bearings as well as angle of elevation and depression.
This youtube video is a summary of the concepts of bearings as well as angle of elevation and depression.
Why do you think that bearings are given with 3 digits historically?
Why do you think that bearings are given with 3 digits historically?
The purpose for 3 digits is clarity of communication.
The purpose for 3 digits is clarity of communication.
When written, a number like 20° could be mistaken as 200°.
When written, a number like 20° could be mistaken as 200°.
Over the radio, if a commander was to call for an artillery strike at a certain bearing: "Target enemy at two-one-four degree bearing" but due to bad reception, the artillery might hear: "Target enemy at two-zzzkt-four degree bearing". This could result in deadly friendly fire if there was no protocol to listen for 3 digits and to echo back the 3 digits back to the commander.
Over the radio, if a commander was to call for an artillery strike at a certain bearing: "Target enemy at two-one-four degree bearing" but due to bad reception, the artillery might hear: "Target enemy at two-zzzkt-four degree bearing". This could result in deadly friendly fire if there was no protocol to listen for 3 digits and to echo back the 3 digits back to the commander.
Explore!
Explore!
Use the applet below to explore and uncover the relationship between the bearing of B from A and the bearing of A from B.
Use the applet below to explore and uncover the relationship between the bearing of B from A and the bearing of A from B.
How is the bearing of A from B related to the bearing of B from A?
How is the bearing of A from B related to the bearing of B from A?
The two angles have a difference of 180°.
The two angles have a difference of 180°.
| (Bearing of A from B) – (Bearing of B from A) | = 180°
| (Bearing of A from B) – (Bearing of B from A) | = 180°