Hi, just trying to understand the full meaning of speed over ground. I do know that it is speed relative to the earths surface. But does this mean that it is based on the earth being perfectly spherical? If a car is driving up a steep hill at 60km/h (as displayed on the cars speedo), is the (SOG) speed over ground likely to be slower, lets say 58km/h (even though the car is on the "ground")??
Have I understood this correctly?
Thanks in advance