Which measurement type is used for a baseline measurement?

• A. Baseline
• B. Triangulation
• C. Polar
• D. Rectangular

Answer: (A)

Baseline measurement refers to directly measuring the straight-line distance between two control points. This length sets the scale and provides the anchor for the whole survey network, so it must be determined with the highest accuracy using precise instruments. The other methods—triangulation, polar, and rectangular—are ways to obtain additional data after the baseline is established: triangulation uses measured angles to derive other distances, polar uses angles (often along with distance estimates) from a station to targets, and rectangular collects coordinates in a grid system. Since the question asks which type is used to obtain the baseline itself, the baseline measurement is the correct fit.