Which term describes underwater depth measurement of sea or lake floors?

Which term describes underwater depth measurement of sea or lake floors?

• A. Uranography
• B. Photogrammetry
• C. Bathymetry
• D. Orthodrome

Answer: (C)

Bathymetry is the study and mapping of underwater depths and the shape of the seabed. It involves measuring how deep the water is at many points and then creating charts that show depth, underwater contours, and features like trenches, ridges, and shelves. In practice, depth measurements are collected with sonar devices—such as single-beam or multi-beam echosounders—and refined into bathymetric maps used for navigation, coastal planning, and scientific understanding of underwater terrain. The other terms describe different ideas. Uranography relates to mapping the heavens or celestial bodies, photogrammetry uses photographs to measure and map surfaces (often on land), and orthodrome refers to the shortest line between two points on a sphere (a great-circle route), not depth measurement.

Bathymetry is the study and mapping of underwater depths and the shape of the seabed. It involves measuring how deep the water is at many points and then creating charts that show depth, underwater contours, and features like trenches, ridges, and shelves. In practice, depth measurements are collected with sonar devices—such as single-beam or multi-beam echosounders—and refined into bathymetric maps used for navigation, coastal planning, and scientific understanding of underwater terrain.

The other terms describe different ideas. Uranography relates to mapping the heavens or celestial bodies, photogrammetry uses photographs to measure and map surfaces (often on land), and orthodrome refers to the shortest line between two points on a sphere (a great-circle route), not depth measurement.