"magnetic variation." YourDictionary, n.d. Web. 12 October 2018. <http://www.yourdictionary.com/magnetic-variation>.
magnetic variation. (n.d.). Retrieved October 12th, 2018, from http://www.yourdictionary.com/magnetic-variation
(plural magnetic variations)
(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.
(cartography) In cartography, the annual change in direction of the horizontal component of the Earth's magnetic field.
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