What is magnetic variation?

Magnetic variation, also known as magnetic declination, refers to the difference between magnetic north—the direction a magnetic compass points—and true north, which is the direction along the Earth's surface towards the geographic North Pole. This variation is influenced by the Earth's magnetic field and can change based on your geographic location.

Understanding magnetic variation is crucial for navigation and map reading, as it allows navigators to correct compass readings to align them with true north. This is especially important in aviation and marine navigation, where accurate directional information is critical for safe travel.

The other options do not accurately define magnetic variation. The angle of descent for magnetic compasses pertains to how a compass needle pivots, not the difference between norths. Variation in altitude affecting magnetic readings is not a recognized factor. Lastly, the adjustment required for GPS accuracy is related to satellite positioning and calculations rather than the magnetic differences discussed in the context of navigational headings.