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High-Tech Channel Hitachi High-Tech GLOBAL

Length equivalent to one minute of latitude

Symbol: nm / Base data: International nautical mile.
1 nautical mile = 1852 m

Conveniently devised for navigation

This unit measures the length of the sea surface. It was determined by a length equal to one minute of latitude. Navigation was based on astronomical observations in olden times, so this unit came in rather useful. This unit was also used for the “200 nautical mile exclusive economic zone” that is often mentioned in territorial disputes.