Βασικοί όροι στη δημοσιογραφική τοπογραφία και τη γεωχωρική τεχνολογία.
The point on the celestial sphere directly above the observer's position, used as a reference in astronomical and surveying observations.
The angle measured from the zenith (directly overhead) downward to a celestial body or surveying target, ranging from 0° at zenith to 180° at nadir.