The compass - even today, continues to be an invaluable tool on board for determining a predetermined direction as a navigational course, bearing direction, or cardinal direction. The oldest version of a compass, the rear sight, targets the North Star on clear nights to provide direction.
The classic compass is the magnetic compass, which allows the user to determine magnetic north by using the earth's magnetic field. Despite the existence of positioning systems like GPS or GLONASS, the magnetic compass is still often used. Navigation systems can usefully complement navigation based on the use of a star map and compass, but they do not act as a total replacement. Besides the dependence of electronics on board, course angle determination with a compass is easier and more precise than with a navigational device, provided that this device does not include an electronic magnetic compass.