Gauging nautical milage

1 naitical mile = roughly 1900 meters each square on the map is 1000 meters, so we can round off that 2 squares is roughly 1 nautical mile. I tested this using the games stats under my profile (meters sailed) I set up on the edge of a square wrote down current meters, sailed to the next square and subtracted the after from the before wound up with a difference of 999 which we can just round to 1000. Hope this clears up and confusion.