Both, nautical mile and metre are derived from earth’s dimensions: One nautical mile is an arc second at the equator, i.e. its circumference is 360·60 NM. One metre originally was 1/40000 of the circumference through the poles (or 1/10000 of the distance from a pole to the equator).
It’s very easy if you remember that are 3 feet in a yard, 22 yards in a chain, 10 chains in a furlong, and 8 furlongs on in a mile!
but what if they’re above water and we need to use nautical miles?
Those are actually much saner: 10 cables in a nautical mile and 100 fathoms in a cable.
Both, nautical mile and metre are derived from earth’s dimensions: One nautical mile is an arc second at the equator, i.e. its circumference is 360·60 NM. One metre originally was 1/40000 of the circumference through the poles (or 1/10000 of the distance from a pole to the equator).
Ah, now it makes sense!