SINCE the year 1701, when Halley published his famous chart showing curves of equal magnetic variation for the Atlantic and Indian Oceans, the construction of similar charts, amended and enlarged ...

THE activity of the United States Coast and Geodetic Survey Department in carrying out a magnetic survey of the States and outlying territories has long been a subject of interest to magneticians ...

There is all sorts of science involved but, for the less scientific among us, it is simple. The maps we use on the ... details and receive the current magnetic variation for your desired location.