A nautical chart is a map of the sea. Just as a map helps us navigate on land, a nautical chart helps those traveling on the ocean get where theyíre going safely and efficiently.

In 2017, $1.6 trillion worth of goods moved through U.S. ports. With all that traffic, itís important that those navigating through our ports and along our coastlines have the information they need about the shape of the shoreline and seafloor, water depths, potential hazards in the water, buoys, anchorages, and other features.


Federal laws say most commercial vessels must have nautical charts while traveling in U.S. waters. NOAA's Office of Coast Survey makes and updates all charts of U.S. coastal waters, the Great Lakes, and waters surrounding U.S. territories. So how do these important resources get made and updated? Itís a continuous process that involves many people from different disciplines and organizations.





A nautical chart is a map of the sea. Just as a map helps us navigate on land, a nautical chart helps those traveling on the ocean get where theyíre going safely and efficiently.

In 2017, $1.6 trillion worth of goods moved through U.S. ports. With all that traffic, itís important that those navigating through our ports and along our coastlines have the information they need about the shape of the shoreline and seafloor, water depths, potential hazards in the water, buoys, anchorages, and other features.


Federal laws say most commercial vessels must have nautical charts while traveling in U.S. waters. NOAA's Office of Coast Survey makes and updates all charts of U.S. coastal waters, the Great Lakes, and waters surrounding U.S. territories. So how do these important resources get made and updated? Itís a continuous process that involves many people from different disciplines and organizations.





No map projection is a perfect picture of our world. Each projection method introduces its own distortions, so cartographers have to pick the right projection for the job. For charts, that's usually Mercator. Lines of latitude and longitude on the Mercator projection meet at right angles, and any constant compass heading can be drawn on a chart with a straight line. Thatís why mariners have used Mercator charts since the 16th Century.

Sea Change
But the story doesnít end there. Our ocean and coasts are always changing. Storms and other natural processes change harbor depths and the shape of coastlines. New channels, harbors, piers, wharves, marinas, pipelines, communications cables, bridges, or buoys get added. Recommended travel routes change. All of these updates have to be put on the charts.

And, of course, weíre always working to improve the quality of our charts. Many charts are based on data collected in the very early days of surveying, when data was collected with methods that are now outdated. These charts are accurate, but incomplete. With todayís technology, NOAA is working to complete and update charts for these underserved areas, such as Alaska and the Arctic.

NOAA releases updates to its charts weekly. You can visit the Weekly Updates page to view these updates. You can also read more about how to find any of our charts.



https://oceanservice.noaa.gov/naviga...al-charts.html