Great-circle distance (source code)

= Great-circle distance
{wiki=Great-circle_distance}

Great-circle distance is the shortest path between two points on the surface of a sphere. It is based on the concept of a "great circle," which is a circle that divides the sphere into two equal hemispheres. Great-circle distances are significant in navigation and geography because they represent the shortest distance across the earth's surface, accounting for its curvature.