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Great Lakes: Lake Champlain to Lake of the Woods

National Oceanic and Atmospheric Administration

The Big Picture
This navigational chart provides mariners with a broad overview of the Great Lakes and their connecting waterways.

For centuries, the navigational chart has been one of the most fundamental tools available to the mariner. A nautical chart is a graphic portrayal of the marine environment showing the nature and form of the coast, the general configuration of the sea bottom, including water depths, locations of dangers to navigation, and locations and characteristics of man-made aids to navigation, such as buoys, lights, and other markers.

This chart is used in conjunction with much more detailed, larger-scale maps of individual lakes, harbors, and channels. Because of the big-picture view it provides, it is also popular as a decorative wall hanging in offices, homes, restaurants, and other places.

Today, new forms of nautical charts have supplemented traditional paper formats. Raster nautical charts, for example, are digitized charts that can be integrated with GPS (the Global Positioning System) and other geospatial data. With these tools, a ship’s navigator can view charts on a computer screen at many convenient scales while the ship’s position, speed, and heading are indicated on the chart. Although these systems are tremendously useful and convenient, paper charts continue to provide essential backup information.