Which of the following best represents the standard reference used to determine elevations on a map (as described in the source material)?

• A. Datum
• B. Benchmark
• C. Bench mark
• D. Elevation grid

Answer: (C)

Elevations on a map are anchored to a fixed, known point used specifically to tie measurements to a real height. That fixed point is a benchmark. A benchmark is a physical marker with a published, exact elevation above a vertical reference surface (the datum). Surveyors measure from this point to determine the elevations of other features, ensuring consistency across the map. The datum is the reference surface itself, not a specific marker on the ground, and an elevation grid is just a pattern of elevations without providing the precise reference needed to determine absolute heights. That combination makes benchmark the best choice.