Magnetic variation, also known as magnetic declination, represents the angle between true north (geographic north) and magnetic north (the direction a magnetic compass points). It is expressed in degrees east or west, depending on whether magnetic north is east or west of true north. There isn’t a single formula for magnetic variation, as it varies based on location and changes over time due to the Earth’s shifting magnetic field.
In general, magnetic variation is calculated as follows:
- Magnetic Variation is the angular difference between magnetic north and true north, measured in degrees east (E) or west (W).
- Magnetic North is the direction to which a magnetic compass points at the location of interest.
- True North is the geographic or true north direction.