The reported local accuracy is an approximate average of the local accuracy values between this control point and other observed control points used to establish coordinates.

• A. The area of the project boundary
• B. Baseline distances to the base
• C. Elevation differences to two benchmarks
• D. Other observed control points used to establish the coordinates

Answer: (D)

Local accuracy is about how well a point is tied into the surrounding control network. The reported local accuracy being an approximate average of the local accuracy values between this control point and other observed control points used to establish coordinates reflects that the precision of this point depends on its connections to the rest of the network. In a network adjustment, each connection to another control point carries a residual or error component; taking an average of those residuals across all neighboring control points provides a practical measure of how reliably this point’s coordinates fit with the network. The other options don’t describe this network-based linkage: the area of the project boundary is about extent, baseline distances pertain to instrument geometry, and elevation differences to benchmarks relate to vertical checks rather than the local, network-wide integration of coordinates.