The Draw map button will show you the two points on a map and draw the great circle route between them. The great circle distance is proportional to the central angle. A2 b2 c2 a2 b2 c2 where.
The central angle between the two points can be determined from the chord length.
Distance Between Two Points. Since distance d is positive we can eliminate. Distance between two points. In general we do not need to measure from the 0 mark.