Position on earth
A position on Earth is determined by the intersection of 2 lines: a meridian and a parallel. The meridians are great circles whose planes run through the north and south poles and the center of the earth. Parallels run parallel to the equator. Every meridian and parallel intersect twice. The equator is the zero parallel, the parallels to the North Pole from zero to 90 degrees North Latitude (N), the parallels to the South Pole zero to 90 degrees South Latitude (S). The zero meridian has been established as the meridian that runs across Greenwich in England. The meridians from zero to the west to 180 degrees west longitude (W) and those from zero to 180 degrees to the east east longitude (OL). The values that indicate the position are also called coordinates.
A circle has 360 degrees, 1 degree has 60 minutes. The average circumference of the Earth is 40.000 km, which divided by 360 and then divided by 60 is 1851 meters = 1 nautical mile is therefore 1 minute of the circumference and is indicated by '
