noun
: the process of determining the magnetic elements at various points on the earth's surface including local variations (as for making isomagnetic charts or as a means of prospecting for ore)
noun
: the process of determining the magnetic elements at various points on the earth's surface including local variations (as for making isomagnetic charts or as a means of prospecting for ore)
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012