trigonometric leveling

Trigonometric leveling is a surveying technique used to determine the elevations of points, especially when direct measurement is difficult or impossible. It relies on trigonometric principles, specifically the use of angles and known distances to calculate unknown heights.12

This method is employed when accurate elevations are not readily available or when points are inaccessible. By measuring vertical angles from two points with known positions and elevations to an unknown point, surveyors can use trigonometry to compute the differences in elevation. This is distinct from using a surveyor's level, which directly measures height differences using a telescope and a graduated rod. Trigonometric leveling is a valuable tool in modern surveying, complementing other methods like trilateration and triangulation.134