Which survey category is used for large-area networks with geoid-spheroidal considerations?

• A. Control Surveys
• B. Geodetic Control Surveys
• C. Public Land Surveys
• D. Isolated Surveys

Answer: (B)

Large-area networks require a precise, consistent reference framework that models the Earth's shape and vertical datum. That’s provided by a geodetic control survey. It establishes a network of precisely measured control points across a region using geodetic datums, linking positions on an ellipsoid and heights to the geoid (mean sea level). This setup lets measurements be transferred reliably over long distances and across wide areas, because horizontal coordinates are tied to a specific geodetic framework and vertical differences are converted to a common datum using geoid models. Other survey types serve more local or cadastral purposes and do not emphasize the geodetic framework needed for large-area networks.