Which term denotes a geodetic datum for horizontal control in which points are mapped onto a specified ellipsoid?

• A. Geodetic Datum
• B. Ellipsoid Model
• C. Sphere
• D. Horizontal Datum

Answer: (D)

In surveying, a horizontal datum defines how horizontal positions are referenced using a specific ellipsoid. It sets the origin, orientation, and the ellipsoidal model so that all latitude/longitude coordinates are tied to that surface. That makes it the term that denotes a geodetic datum used for horizontal control with points mapped onto a specified ellipsoid.

The broader term “geodetic datum” would be too general, since it can refer to horizontal, vertical, or a combination of reference surfaces. The “ellipsoid model” is the mathematical surface itself, not the datum. A “sphere” is just a simpler, less accurate reference surface. So the horizontal datum is the appropriate label for this concept.