Bench Mark

Bench marks, in the context of drafting, surveying, and mapping instruments, refer to fixed reference points used to establish elevations and measurements in a given area. They are typically permanent markers or monuments that are precisely surveyed and recorded.

Bench marks are crucial in surveying and mapping as they provide a consistent and reliable reference for determining the elevation of other points in the vicinity. They serve as a starting point for establishing vertical control and are used to ensure accurate measurements and mapping.

In the supply class of drafting, surveying, and mapping instruments, bench marks may include items such as leveling rods, surveying tripods, laser levels, total stations, theodolites, and GPS receivers. These instruments are used to measure and record data related to elevations, distances, angles, and coordinates, which are then used to establish and reference bench marks.

It is important to note that bench marks are typically established and maintained by government agencies, such as national mapping agencies or local surveying departments. They are often marked with a distinctive symbol or inscription and are periodically checked and updated to ensure their accuracy and reliability.