directionbearing

A direction bearing is a navigational term that describes the angle of a line of position relative to a reference direction. This reference direction is most commonly the north-south line, though other references such as east-west or a ship's heading can also be used. Bearings are typically measured in degrees, with 0 degrees representing north, 90 degrees representing east, 180 degrees representing south, and 270 degrees representing west.

There are two common conventions for expressing direction bearings. True bearing uses the geographic North Pole as the reference point. Magnetic bearing uses the Earth's magnetic north pole as the reference, which can differ from true north. Compass bearing is the direction indicated by a magnetic compass, which is subject to magnetic variation and deviation. Relative bearing is measured from the heading of the vessel or aircraft, with 0 degrees directly ahead, 90 degrees to starboard (right), 180 degrees directly astern (behind), and 270 degrees to port (left).

Understanding and accurately determining direction bearings is fundamental to navigation, whether by land, sea, or air. It allows individuals to plot courses, identify the location of objects, and maintain awareness of their position and the direction of travel. Instruments such as compasses, sextants, and GPS devices are used to measure and calculate bearings.