Distance on an Ellipsoid of Revolution ORS
• The red curve A to B is the normal section at A
• The red curve B to A is the normal section at B
• The green curve, the minimum distance path on the surface of an ellipsoid of revolution, is called a geodesic
• There is no plane that contains the geodesic
• The length of a geodesic is an incomplete elliptic integral
• The curvature in the figure is exaggerated for the purpose of exposition
– For short distances, all three curves have nearly the same length
• When an environmental model is added, e.g., terrain, minimum distance paths on an ellipsoid are almost never geodesics