Compass

 

Editorial review

A compass is a navigational instrument made up of a magnetized needle that aligns with the earth's magnetic field. It thus indicates magnetic North, to be distinguished from the geographic North Pole. The difference between the two directions at a given location is called the Earth's magnetic declination. Depending on the precision required, this difference is accommodated or a compensation chart is used. Observed from France in 2018, the two directions are more or less identical but can present up to more than 20 degrees of difference in certain places of the globe.