Cartography
Cartographers go around and collect data points to create a map. People used to have to go out personally and try to figure out where they were. Now there is multibeam sonar which could either set out sound waves to track how long it takes to bounce back, or they use animals in the ocean to listen to the sounds that they make. This makes it easy to paint a picture of what the oncean looks like and what animals are living within in. This technology has made it way easier for scientists to track ocean currents, animals, depth, etc.
CDT means Conductivity, Depth, and Temperature. It helps scientists locate places that they want to find. It also helps them calculate water currents using conductivity and temperature to calculate the density of the current. It has many chambers on it and each chamber collects the water and stores it until it needs to be tested. The interesting part of this is the fact that we can calculate currents and have machines that test water.
A compass rose is a tool to make it easier to direct to a place. A compass rose points north, south, east, and west. It has two or three circles on it, each circle is subdivided into segements. The outer circle is divided into 360 degrees. The inner circle is the magenetic direction also in degrees.