trigonometric leveling example

hello i am engineer gohar shah in this video i am presenting that what is trigonometric leveling ? This is the branch of levelling in which the relative elevation (Reduced level) of different Stations are determined from the observed vertical angles and know or computed horizontal distance. OR Trigonometric Leveling is the branch of Surveying in which we find out the vertical distance between two points with the help of some measurements of the vertical angles and the known distances.The known distances are either assumed to be horizontal or the geodetic lengths at the mean sea level (MSL). so now when The base of the object is not accessible then how we can calculate reduced level of object ? In such a case we have to take the two angular observations of the vertical angles.The instrument is shifted to a nearby place of known distance, and then with the known distance between these two and the angular observations from these two stations, we can find the vertical difference in distance between the line of sight of the instrument and the top point of the object. #trigonometric levelling #trigonometrical levelling #Civil Engineering ZoNe