What is the main angle measuring instrument in measuring work? What angle can the tower measure and what angle can be measured?
60 points system, that is, a week for 360 degrees, 1 degrees for 60 ', and 1' for 60'. The radian uses 2 of the 1 - Pi of the circumferential angle. 1 radian equal to 57 degrees, 17 ', 45'. In addition, military units are usually used as measuring angles. For the 1 mil of arc length is roughly equal to the radius of the 1/1000, take the circular angle 1/6000 is 1 mil. Angle measurement mainly uses theodolite. When the placement angle of theodolite, the instrument center and station signs center on the same vertical line, using the leveling instrument on the level of alidade, horizontal angle or vertical angle observation.
The act of measuring a horizontal angle or right angle. The horizontal angle is the angle formed by the vertical projection of the direction line from one point to the two target on the horizontal plane. A vertical right angle is the angle between the point of the target and the direction of the target in the same vertical face. Usually in the direction of a horizontal or zenith direction. The angle between the horizontal and the target is called the height angle. The angle between the zenith direction and the target direction is called the zenith distance. The angle measurement is usually made by 60 point system and radian system.
Angle measurement is divided into horizontal angle measurement and vertical right angle measurement. Horizontal angle measurement is used to determine the plane position of ground points, and vertical angles are used to determine the distance between elevation and points indirectly.
