°(military nautical navigation) In navigation, at a given place and time, the horizontal angle between the true north and magnetic north measured east or west according to whether magnetic north lies east or west of true north.
°In cartography, the annual change in direction of the horizontal component of the Earth's magnetic field.
°(military nautical navigation) In navigation, at a given place and time, the horizontal angle between the true north and magnetic north measured east or west according to whether magnetic north lies east or west of true north.
°In cartography, the annual change in direction of the horizontal component of the Earth's magnetic field.