Bathymety is the measurement of the depth o water in oceans, rivers, or lakes. Bathymetic maps look a lot like topographic maps, which use lines to show the shape and elevation of land features.
On topographic maps, the lines connect points of equal elevation. on bathymetric maps, they connect points of equal depth. Acircular shape with increasingly smaller circles inside of it can indicate an ocean trench. It can also indicate a seamount, or underwater mountain.
In ancient times, scientists would conduct bathymetric measurements by throwing a heavy rope over the side of a ship and recording the length of rope could also only measure depth one point at a time. To get a clear picture o the seafloor, scientists would have had to take thousands of rope measurements.
More often, scientists and navigators estimated the topography of the seafloor. Seafloor. Sometimes, the seafloor's hills and valleys were easy to predict. Other times, an ocean trench or sandbar would surprise navigators. This could lead to danger for a ship's crew and economic losses if the ship it the sandbar and lost its cargo.
