Great-circle navigation
（重定向自Great circle course）
![Figure 1. The great circle path between (φ1, λ1) and (φ2, λ2).](/Images/godic/202501/16/Sphere_geodesic_4sigma.svg4724.png")
![Figure 2. The great circle path between a node (an equator crossing) and an arbitrary point (φ,λ).](/Images/godic/202501/16/Sphere_geodesic_2sigma.svg4724.png")
Great-circle navigation is the practice of navigating a vessel (a ship or aircraft) along a great circle. A great circle track is the shortest distance between two points on the surface of a sphere; the Earth isn't exactly spherical, but the formulas for a sphere are simpler and are often accurate enough for navigation (see the numerical example).