What geographical concept limits visibility due to the curvature of the Earth?

• A. Computed visibility
• B. Variation
• C. Geographic range
• D. Deviation

Answer: (C)

The concept that limits visibility due to the curvature of the Earth is geographic range. This refers to the maximum distance at which an observer can see an object, which is influenced by the Earth's curvature. As you move farther away from an object, the curvature causes it to eventually dip below the horizon, limiting visibility.

The height of the observer and any obstructions in the environment can also affect geographic range, but fundamentally, it is the shape of the Earth that imposes a natural limit on how far one can see. Understanding geographic range is crucial in navigation and operations at sea, as it helps determine the point at which vessels or landmasses can no longer be seen due to this curvature.

The other options—computed visibility, variation, and deviation—refer to different navigational or geographical concepts that do not specifically relate to the physical limitations imposed by the curvature of the Earth. Computed visibility typically refers to a calculated distance one can see under certain atmospheric conditions, while variation and deviation relate to magnetic navigation and compass errors. Thus, geographic range is the most suitable concept in the context of visibility limitations caused by the Earth's curvature.