What does trigonometric leveling involve?

Trigonometric leveling is a method that accurately determines height differences between points based on the measurement of angles and distances. This technique employs trigonometry to calculate the vertical distances by measuring angles from horizontal lines and the distance to a target point.

When surveyors apply this method, they typically use instruments such as theodolites or total stations. By measuring the angle of elevation or depression to the point of interest from a known height, along with the horizontal distance to that point, they can calculate the height difference using basic trigonometric relationships. This method is particularly useful in situations where direct leveling may be impractical, such as across valleys or in rugged terrain.

Other options do not accurately describe trigonometric leveling. Using GPS coordinates pertains to different surveying methods focused on global positioning. Computing land area involves calculations related to planimetric measurement rather than elevation changes, while evaluating land contours concerns modeling the shape of the terrain, which is more related to contour surveying techniques rather than trigonometric leveling specifically.