A nautical mile is slightly longer than a mile on land, equaling 1.1508 land-measured (or statute) miles. ... Nautical charts use latitude and longitude, so it's far easier for mariners to measure distance with nautical miles.

Why don't we use nautical miles on land?

The logical question is, why not miles per hour? Ships use longitude and latitude as their historical form of navigation. So it was natural to use nautical miles because 1 nautical mile is one minute of arc in the latitude world.

Why is a land mile different from a nautical mile?

The familiar land mile is 5,280 feet, is called a statute mile, and it's based on paces. On the other hand, the nautical mile is used for distances on the ocean and doesn't have a tangible equivalent like paces. It's a mathematical calculation based on degrees of latitude around the equator.