When you’re out boating on unfamiliar waters, you really should have the official navigational charts (maps for the water) for that particular body of water. In addition, you ought to carry a compass and a GPS unit, if you have one.
The chart provides a scale drawing of waterways, submerged contours, approximate water depths, and landmasses. Your compass always tells you which way is north, and the GPS gives your position in longitude and latitude. To keep track of your charts, compass and GPS while you’re trying to drive the boat can be a real handful.
A chart plotter combines the functions of your charts, compass, and GPS into one, easy-to-use device.
How it Works
Your chart plotter contains electronic versions of your paper navigational chart, and displays portions of this chart on the display screen. The chart plotter also receives information from the GPS, allowing the chartplotter to graphically indicate your boat’s location as it relates to the navigational chart.
So rather than spreading the paper chart out on the console to try to figure out where you are, you can look at the chartplotter’s display for a real-time representation of your location.
As you might expect, a hand-held GPS chart plotter has a small screen that can only show a tiny portion of a navigational chart at a time. Larger units, with bigger displays, have the ability to put more of the chart on the screen—making navigation a lot easier. So, in this case at least, more is better.