Great Circle: A circle on the earth’s surface whose plane passes through its centre, and bisects it into two hemispheres. Two opposing meridians together form a Great Circle. The shortest distance between any two points on the earth’s surface is the arc of the Great Circle which passes through them. 0° latitude forms a Great Circle. (The latitude or longitude 75°W should be combined with 75°E to obtain the Great Circle).
2014-09-13