Theodolite
A theodolite /θiːˈɒdəlaɪt/ is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are used mainly for surveying applications, and have been adapted for speci...
Theodolite - Wikipedia
Gyrotheodolite
A gyro-theodolite is a surveying instrument composed of a gyroscope mounted to a theodolite. It is used to determine the orientation of true north by locating the meridian direction. It is the main in...
Gyrotheodolite - Wikipedia