Answer:Bathymetry
Explanation:
Bathymetry is what measures the depth of an ocean and the charting of shape. Bathymetry uses vertical distance from the ocean to the surface at the bottom of the mountains , plains and valleys.
Bathymetric also measures the depth of rivers and lakes. Bathymetry maps is displayed similarly to topographic maps in which lines are used showing shape and elevation of world features.
The difference is on topographic maps these lines shows connection points of equal elevation whilst bathymetric maps shows connection of equal depth
A circular shape with closely small circles indicate a trench in an ocean or underwater mountain.
