Towards or away from the center is the height, no? As in, you’re the bird at height Z observing the x-y plane under you, and the Z axis goes into you. Or away f

Towards or away from the center is the height, no? As in, you’re the bird at height Z observing the x-y plane under you, and the Z axis goes into you. Or away from you if you happen to be a mole under ground.