What is the primary purpose of a control survey?

• A. To measure only elevations for a single point.
• B. To determine weather patterns.
• C. To provide precise locations of horizontal and vertical positions for boundary determination, mapping for aerial photographs, construction staking, or other needs.
• D. To replace all local measurements with estimated values.

Answer: (C)

A control survey aims to establish a network of precisely known points that provide reliable reference positions in both horizontal and vertical directions. These control points are tied to a common coordinate system and elevation datum, so subsequent work can align accurately to them. This framework lets boundary determinations, mapping for aerial photographs, construction staking, and other surveying tasks be positioned consistently across large areas or projects, with minimized error accumulation.

So the primary purpose isn’t about weather patterns, nor about measuring elevations for a single point, nor about replacing local measurements with estimates. It’s about creating a stable, highly accurate reference network that all future surveys can rely on.