Bearing (navigation)

[1][3] In nautical navigation the absolute bearing is the clockwise angle between north and an object observed from the vessel.

The difference between a magnetic bearing and a compass bearing is the deviation caused to the compass by ferrous metals and local magnetic fields generated by any variety of vehicle or shipboard sources (steel vehicle bodies/frames or vessel hulls, ignition systems, etc.

Since World War II, relative bearings of such diverse point sources have been and are calibrated carefully to one another.

The United States Navy operates a special range off Puerto Rico and another on the west coast to perform such systems integration.

The measurement of relative bearings of fixed landmarks and other navigational aids is useful for the navigator because this information can be used on the nautical chart together with simple geometrical techniques to aid in determining the vessel's position, speed, course, etc.

The measurement of relative bearings of other vessels and objects in movement is useful to the navigator in avoiding the danger of collision.

For example: A bearing can be taken to a fixed or moving object in order to target it with gunfire or missiles.

A standard Brunton compass , used commonly by geologists and surveyors to obtain a bearing in the field
Azimuths and bearings.
A compass rose, showing absolute bearings in degrees .
The bearing between Cape Town and Melbourne along the geodesic (the shortest route) changes from 141° to 42°. Azimuthal orthographic projection and Miller cylindrical projection .
A and B are near the North Pole and facing each other. Though A is facing east, B is not facing west. If B were to face west, her direction (dashed arrow) would be tangential to her latitude circle (dashed circle). Only on the equator is it true that if A faces east and B faces west that they can face each other.
Latitude circles near the North Pole are shown in red. For A and B to face each other, A has to look East but B not to the West. If B were to look West, she would see a bear eyeing her as his next meal. For A and C to face each other, both would have to face North.