NOAA considers a historical map or chart any map or chart that is not used today because it is out of date The Office of Coast Survey maintains a historical map and chart collection of over 35,000 scanned, high-resolution images. The collection includes some of the nation’s earliest nautical charts, bathymetric maps, city plans, and Civil War battlefield maps.

Nautical charts are one of the most fundamental tools available to mariners, depicting the nature and form of the coast, the general configuration of the sea bottom, water depths, locations of dangers to navigation, locations and characteristics of human-made aids to navigation, and other features useful to the mariner.

Additionally, many of historical charts also depict events reflecting the geographic landscape at that time. For example, within the Office of Coast Survey's collection is a Chattanooga battlefield map from 1863 which is considered one of the best Civil War maps at that time.

While the historical map and chart collection dates back to the 1700s, the Office of Coast Survey, which formed in 1807 as the first federal scientific agency, produced its first charts in the early 1840s.

Electronic copies of images within the collection are available, by free download, to the public.


For more information:
Historical Map and Chart Collection, Office of Coast Survey

Charting a More Perfect Union: Special Collection of Civil War Charts

Diving Deeper: Episode 29 (December 16, 2010) - Historical Charts and Maps

New Online, a NOAA Civil War Collection



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The NOAA Air Gap system is a tool that measures the clearance between the water surface and the bridge.

Air gap measurements are updated every six minutes to account for changes in water level and bridge height, due to bridge traffic, air temperature, and other factors. Data on air gap along with real-time data on water conditions like tides, currents, and winds, help ship captains safely enter and leave U.S. ports. This information is critical for a ship captain to safely navigate a ship under a bridge.

For more information:

Center for Operational Oceanographic Products and Services

Physical Oceanographic Real Time System

Ship Under a Bridge

NOAA's Air Gap Technology Sends USS New York Down the Mississippi River for Sea Trials




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More specifically, the EEZ includes waters three to 200 miles (five to 322 kilometers) offshore (or nine to 200 miles – 14.5 to 322 kilometers – offshore in western Florida and Texas). Coastal states are responsible for inshore waters out to three miles (five kilometers) of the coast (or nine miles, 14.5 kilometers, off the west coast of Florida and off Texas).

Within the EEZ, the U.S. has

sovereign rights for the purpose of exploring, exploiting, conserving and managing natural resources, whether living and nonliving, of the seabed and subsoil and the superjacent waters and with regard to other activities for the economic exploitation and exploration of the zone, such as the production of energy from the water, currents and winds; jurisdiction as provided for in international law with regard to the establishment and use of artificial islands, installations, and structures, marine scientific research, and the protection and preservation of the marine environment, and other rights and duties provided for under international law (Presidential Proclamation No. 5030 of March 10, 1983). For more information:
Office of Coast Survey
Download EEZ Limits



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NOAA's navigation response teams, part of the Office of Coast Survey, conduct hydrographic surveys of the ocean floor, monitoring for changes in depth or hazards below the surface of the water that could pose great danger to vessel traffic above.

Six navigation teams are strategically located around the country, ready to collect data needed to inform officials of navigational hazards and to help the U.S. Coast Guard find alternative routes for commercial and military ships. NOAA also uses the survey data to update NOAA's national suite of nautical charts—"roadmaps" for mariners. For more information:
Office of Coast Survey
Navigation Response Teams (Diving Deeper podcast, 5.19.10)
Hydrographic Surveying
NOAA's Navigation Response Teams
Rapid Response for Disasters

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Bathymetric data, which includes information about the depths and shapes of underwater terrain, has a range of uses, including:

Bathymetric surveys provide the data on which nautical charts are based.  These charts guide mariners much as road maps guide motorists, ensuring safe and efficient maritime transportation. Bathymetric maps are becoming increasingly important as scientists seek to learn more about the effects of climate change on the environment. Bathymetric surveys can alert scientists to ongoing and potential beach erosion, landslides, sea-level rise, and subsidence (land sinking). Scientists also need current/updated bathymetric survey data, which is critical to support the creation and development of hydrodynamic models. Bathymetry is also a key element of biological oceanography.  The depth and characteristics of the seabed define the habitat for benthic (bottom-dwelling) organisms, and are fundamental parameters of marine ecosystems.  Scientists increasingly rely on high-resolution bathymetry in their efforts to determine where fish and other sea life will feed, live, and breed. For more information:
Office of Coast Survey
Sea-floor Mapping, NOS Education

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The term “bathymetry” originally referred to the ocean’s depth relative to sea level, although it has come to mean “submarine topography,” or the depths and shapes of underwater terrain.

In the same way that topographic maps represent the three-dimensional features (or relief) of overland terrain, bathymetric maps illustrate the land that lies underwater. Variations in sea-floor relief may be depicted by color and contour lines called depth contours or isobaths.

Bathymetry is the foundation of the science of hydrography, which measures the physical features of a water body.  Hydrography includes not only bathymetry, but also the shape and features of the shoreline; the characteristics of tides, currents, and waves; and the physical and chemical properties of the water itself.

For more information:
Office of Coast Survey
Sea-floor Mapping, NOS Education

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Nautical charts show what is in, under, and around the water, to help mariners transit our waters safely. The time it takes to develop a new nautical chart varies and it depends on the intensity of the ship travel in the area and the availability of resources to develop the new chart.

For example, if a new nautical chart is needed in an area that has current survey data, a new chart can be produced in six to 12 months. In a more remote area such as the north slope of Alaska, a new chart may take several years to develop because of the amount of survey work that needs to be done.

Another consideration in developing new nautical charts is the length of the survey season in different locations. The survey season is the time available to collect the data needed to develop a new chart. The survey season in Alaska is only a few months each year so it may take several years to collect the necessary data to develop a new chart. The Gulf of Mexico, on the other hand, can be surveyed during almost any time of the year.

It is easier to update existing nautical charts, but these updates can still be time and labor intensive. An estimate to complete an update for an existing chart is three to four weeks. Ports with high shipping activity, such as the Port of Long Beach or New York Harbor, may be updated as frequently as two or three times per year because of the intensity of traffic and the high value of cargo in these areas.

For more information:
Office of Coast Survey
A History of Charting America's Waters, NOAA 200th Anniversary Web Site
Diving Deeper Podcast, Episode 5 (Mar. 23, 2009) - What is a nautical chart?
Nautical Charts: A Message in a Bottle, NOS Education

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Soundings are water depth measurements that indicate how deep the water is in a particular area in either feet or fathoms. A fathom is a nautical unit of measurement and is equal to six feet.

On a chart, sounding data with the same values are usually connected with a line known as a depth contour, similar to the topographic lines or surface features that you see on a map. Depth contours present a picture of the bottom 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, locations and characteristics of human-made aids to navigation, and other features useful to the mariner.

For more information:
Office of Coast Survey
A History of Charting America's Waters, NOAA 200th Anniversary Web Site
Diving Deeper Podcast, Episode 5 (Mar. 23, 2009) - What is a nautical chart?
Nautical Charts: A Message in a Bottle, NOS Education

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A nautical chart is one of the most fundamental tools available to the mariner. It's 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, locations and characteristics of human-made aids to navigation and other features useful to the mariner.

The nautical chart is essential for safe navigation. In conjunction with supplemental navigational aids, it is used by the mariner to lay out courses and navigate ships by the shortest and most economically safe route. Over 98 percent of the nation’s cargo is carried by waterborne transportation—and all of those ships rely on nautical charts to find their way.

 

For more information:
Office of Coast Survey
A History of Charting America's Waters, NOAA 200th Anniversary Web Site
Nautical Charts: A Message in a Bottle, NOS Education

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A nautical chart provides a very detailed and accurate representation of the coastline, which takes into account varying tidal levels and water forms, critical to a navigator.

A map, on the other hand, emphasizes land forms, with shoreline represented much less accurately.

A chart is continually updated and is used by navigators to plot courses. A map, on the other hand, is a static document which serves as a reference guide.

Nautical charts also provide detailed information on the area beneath the water surface, which is critical for safe and efficient navigation. Maps provide no information of the condition of a road.

For more information:
Office of Coast Survey
Nautical Charts: A Message in a Bottle, NOS Education

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