What are leveling rods used with in surveying?

Leveling rods, also known as leveling staffs, are specifically designed to work in conjunction with surveyor's levels. In surveying, they serve as a reference point for measuring elevations and differences in height between various points on the ground. When using a surveyor's level, the surveyor sights the leveling rod through the instrument; as the bubble level indicates when the instrument is level, readings can be taken directly from the rod.

This collaboration allows surveyors to establish a precise horizontal plane from which vertical measurements can be accurately determined. Therefore, the relationship between leveling rods and surveyor's levels is fundamental to the process of leveling, which is a key aspect of surveying that ensures accuracy in height measurements.

The other tools mentioned, like GPS devices and theodolites, serve different purposes in surveying and may be used for horizontal measurements, angles, or global positioning, but they do not function in the same direct way with leveling rods as surveyor's levels do. Invar tapes are used for measuring distances but do not relate to height measurements in the same context as leveling rods and levels.