Which term is associated with the concept of measuring depth under water?

Isobaths are lines that connect points of equal depth below the water surface, specifically in a marine or aquatic context. This term is crucial in underwater mapping and oceanography, as it provides important information about the underwater topography and bathymetry. Isobath lines help in understanding the shape and features of sea floors, lakes, or any waterbody, facilitating navigation, resource management, and environmental monitoring.

Isolines generally refer to lines that connect points of equal value on land, such as temperature or precipitation, and do not specifically pertain to water depth. Contour lines are similar but are used to represent elevations on land rather than underwater depths. Elevation lines are used to depict areas of different heights above sea level, which is also not relevant to measuring depth under water. These terms, while related to mapping and geographic phenomena, do not apply to measuring depths as isobaths do.