Displays a map on which the great circle path for one or more
routes is plotted and calculates the distance along each route. Ranges
from one or more locations may also be plotted, along with go/no-go
areas for ETOPS operations at various rule times.
A great circle path is the shortest path on the surface of a sphere between two points on that sphere. Technically, the term geodesic path should be used in this page since Earth is not a true sphere, but the great circle.