Have you ever wondered how far it is betweentwo given coordinates? Then this is the app for you, simply enterlongitude and latitude for two points ans see the distance inkilometers and miles. You can also select the coordinates on a map.

The app is using the great-circle formula to calculate thedistance.

The great-circle or orthodromic distance is the shortestdistance between two points on the surface of a sphere, measuredalong the surface of the sphere (as opposed to a straight linethrough the sphere's interior). The distance between two points inEuclidean space is the length of a straight line between them, buton the sphere there are no straight lines. In non-Euclideangeometry, straight lines are replaced with geodesics. Geodesics onthe sphere are the great circles (circles on the sphere whosecenters coincide with the center of the sphere).