A permanent point of known elevation is called a ___.

• A. datum
• B. reference
• C. origin
• D. benchmark

Answer: (D)

A benchmark is a fixed marker with a precisely known elevation that serves as the reference point for leveling and determining other elevations. It’s designated as permanent so future surveys can rely on the same vertical reference, ensuring consistency across measurements. A datum is a broader reference surface or model used to define elevations over an area, not a specific physical marker; an origin is just the starting point for a coordinate system; and a reference is a general term for a baseline, not the specific marker used for vertical control. Hence, the permanent point of known elevation is called a benchmark.