Which type of leveling uses a telescope and a graduated staff for measuring?

Differential leveling is the method that specifically utilizes a telescope along with a graduated staff for precise measurement of vertical distances between points. In this technique, a leveling instrument (which contains the telescope) is set up at a certain height, allowing the user to line up the telescope with the graduated staff held vertically at a different location. This setup enables the accurate determination of height differences by ensuring that these measurements are referenced relative to a horizontal line of sight.

The purpose of differential leveling is to compute differences in elevation between points, which is essential for various surveying applications such as construction and land development. By using the telescope, the surveyor can align with the staff reading, ensuring a high level of precision in the measurements obtained.

Other methods, while sometimes related to measurements of elevation or height, do not rely on the use of a telescope and graduated staff in this way. For example, barometric leveling uses atmospheric pressure measurements to infer elevation differences, trigonometric leveling employs angles and distances calculated using triangulation methods, and hydrostatic leveling makes use of fluid pressure measurements in connected tubes. These methods do not involve direct line-of-sight measurements between a telescope and a staff as seen in differential leveling.