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Instruments used for setting out right angles - Open cross staff
Unit 1- Surveying
Open cross staff
It is the simplest instrument used for setting out right angle. It consists of either a frame or box with two pairs of vertical slits and is mounted on a pole shod for fixing in the ground. The two pairs of vertical slits give two lines of sights at right angels to each other.
Last modified: Thursday, 28 April 2011, 8:43 AM