An example of bathymetric mapping is typically based on what?

Bathymetric mapping specifically refers to the process of measuring and charting the underwater depth of ocean floors, lakes, and rivers. This technique relies heavily on the use of oceanographic charts, which provide vital information about the seafloor's features based on historical data and various surveying methodologies.

When referring to modeled bathymetry from oceanographic charts, it encompasses the synthesis of data collected through sonar systems, satellite altimetry, and other methods that render a visual representation of underwater topography. This is crucial for navigation, construction, environmental studies, and understanding marine ecosystems.

The other choices do not pertain directly to the field of bathymetric mapping. General topographic maps of cities focus on terrestrial elevations and developments on land rather than underwater features. Surveys of marine life diversity emphasize biological data rather than the physical mapping of sea floors. Satellite imagery of coastlines provides surface level information, which is valuable for coastal studies but does not detail the underwater terrain that bathymetric mapping aims to depict. Thus, modeled bathymetry from oceanographic charts is the appropriate choice as it directly involves the process of mapping underwater topography.