Theodolite
3.1 Introduction and Uses of Theodolite: INTRODUCTION A theodolite is a precise instrument for measuring for horizontal angles, angles of elevation and depression i.e., vertical angle, bearing and azimuth of a line. Theodolite is also used for prolongation of survey lines, finding difference in elevation and setting out engineering works requires higher precision i.e. ranging the highway and railway curves, aligning tunnels, etc. Uses of Theodolite a) To measure horizontal angle accurately. b) To measure vertical angle(zenithal angle) accurately. c) To decide true north by astronomical observation. d) To know the difference in elevation of two points. e) To measure the height of tower, building and depth of a valley f) To measure distance between two points. g) For the alignment fixing of tunnel, road, railway, bridge...