Ocean Pathfinder: Introduction
In 1807, President Thomas Jefferson established the Survey of the Coast. This was utilized to chart the U.S. coastline to make the coasts of our nation safe for navigation. The coast Survey creates charts that show the shape of the currents, coasts, and the depth of coastal waters. The terminology used for collecting information needed for the chart is called “hydrography”. Those who collect and graph the information are called hydrographers and cartography is the process of creating charts and maps. Hydrographers of this generation use sidescan, multibeam sonar, and satellite-based global positioning systems to produce detailed pictures of the sea floor. Before modern hydrographers, their technique for gathering information and graphing were a bit more complex. For many years, hydrographers used lead lines to make depth measurements. A lead line is a rope or a line with a ten-pound lead weight attached to the end. The hydrographer would lower the lead line into the water until the weight reaches the bottom. On the rope indicates markings that would determine how much line has bet let out. The depth soundings made with lead lines are accurate, however they consume a numerous amount of time. They could only give information about single points on the sea bottom.