Isogonic map

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Historical isogonal map from 1860

An isogon map is a map that shows the location of a magnetic compass ( declination ) using isolines ( isogons , lines of the same location). The deviations vary from place to place in the world. Isopores are occasionally also entered in these maps , i. H. Isolines with the same annual change in magnetic declination.

Isogonal maps are geophysical maps.

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