What is Theodolite Device? How does it helps Civil Engineers?
The Theodolite is a precision optical instrument that is used for surveying large spaces and objects in the field. It primarily consists of a movable telescope, mounted on a n adjustable tripod capable of precise measurements at both horizontal and vertical angles. The telescope can be rotated up to 180 degrees. There are two types of Theodolite — Transit and Non Transit. In Transit Theodolites the line of sight of the telescope can be reversed through the rotation of the telescope by 180 degrees about the Trunnion axis (The trunnion axis is the axis about which the telescope transits) in vertical plane.
If the telescope of a theodolite cannot be revolved around the Trunnion axis, it is called as a non-transit theodolite. The non-transit theodolite are the predecessors and are not used anymore in surveying.
Apart from function, theodolites can be classified as digital and analog theodolite. There are two kinds of analog theodolite — Repeating and Directional. The repeating theodolite is used to take multiple measurements on a graduated scale, while the directional theodolites take measurements through a set circle. Digital theodolites are the modern version of these devices, where they eliminate the need of scales and electronically display the readings, some advanced theodolites are also equipped with a laser distance measurement device for higher accuracy.