As is common the Earth is divided into patches by our agreed upon coordinate system of longditude and latitude.
Both of these are measured in degrees. Latitude has a range of 0-90° (North and South). Longditude has a range of 0-180° (East and West).
There are 360° in one revolution (as is common), and each degree is further divided in (arc)minutes, each minute being 1/60 of a degree.
The main unit of distance
The nautical mile is the primary unit of distance used at sea.
- nm means nautical mile
- 1 nm = 1852m (exact)
- 1 knot = 1nm/h
- 1 nm ≈ 1 minute of latitude
- 1 min ≈ 1/60 of a degree of latitude
Thus, travelling 60 nm towards the Equator gets you one degree of latitude closer to it.