Changes

The term '''compass''' can refer to a navigational tool which points in a fixed direction, allowing travelers to find their way by inferring other directions and paths through the process of ''orienteering''.  When used alone the term usually refers to a magnetic compass. The plural ''compasses'' can also refer to a device used for drawing circles.

The term '''compass''' can refer to a navigational tool which points in a fixed direction, allowing travelers to find their way by inferring other directions and paths through the process of ''orienteering''.  When used alone the term usually refers to a magnetic compass. The plural ''compasses'' can also refer to a device used for drawing circles.

Magnetic compasses rely upon [[magnet]]ized pieces of metal, typically floating in liquid to ensure low [[friction]]. These  align themselves with the Earth's magnetic field lines which point at the Earth's magnetic north pole. Magnetic field lines vary from true north (pointing to the geographic north pole) and thus must be adjusted according to information usually found on a map or chart. Maps and charts have a compass rose printed with the deviation from true north noted for the area of coverage of the map. Deviation often occurs due to large mineral deposits which occur in the area of interest.

Magnetic compasses rely upon [[magnet]]ized pieces of metal, typically floating in liquid to ensure low [[friction]]. These  align themselves with the Earth's magnetic field lines which point at the Earth's magnetic north pole. Magnetic field lines vary from true north (pointing to the geographic north pole) and thus must be adjusted according to information usually found on a map or chart. Maps and charts have a [[compass rose]] printed with the deviation from true north noted for the area of coverage of the map. Deviation often occurs due to large mineral deposits which occur in the area of interest.

Deviation from true north can also occur due to the presence of nearby large metal objects, such as ships at sea. At sea, this additional magnetic deviation is tracked, logged, and factored in to reading a magnetic compass in order to determine true north. In an aircraft the aircraft's movement can affect a compass, causing it to give inaccurate readings during turns and other maneuvers.

Deviation from true north can also occur due to the presence of nearby large metal objects, such as ships at sea. At sea, this additional magnetic deviation is tracked, logged, and factored in to reading a magnetic compass in order to determine true north. In an aircraft the aircraft's movement can affect a compass, causing it to give inaccurate readings during turns and other maneuvers.