remiconnesson/oceanservice-noaa-facts huggingface dataset:
# How do I get NOAA nautical charts?

## Head to the NOAA Coast Survey website for the latest charting products.

![Two different renderings of NOAA Electronic Navigational Chart (NOAA ENC®) data of the Columbia River, Oregon.](chart-compare2.jpg "Chart of Intracoastal Waterway Laguna Madre Middle Ground to Chubby Island")

Two different renderings of NOAA Electronic Navigational Chart (NOAA ENC®) data of the Columbia River, Oregon. The top image is from an Electronic Chart Display and Information System (ECDIS) and the bottom image is output from the NOAA Custom Chart application.

NOAA’s Office of Coast Survey is the nation’s chartmaker, providing thousands of electronic navigational charts covering 95,000 miles of shoreline and 3.6 million square nautical miles of ocean, coastal, and Great Lakes waters to the outer limits of the U.S. Exclusive Economic Zone. Here’s a quick overview of the nautical charts that NOAA produces.

-   The **[NOAA Electronic Navigational Chart](https://nauticalcharts.noaa.gov/charts/noaa-enc.html)** (NOAA ENC®) is NOAA's premier nautical chart product. The charts are used on the navigation systems of many types of ships and recreational boats, as well as large commercial vessels that use a sophisticated navigational computer called an Electronic Chart Display and Information System (ECDIS).
    
-   **[NOAA Custom Chart](https://devgis.charttools.noaa.gov/pod/)** is an application that enables users to create their own custom nautical charts, derived from the latest NOAA ENC data.
    
-   **[United States Coast Pilot®](https://nauticalcharts.noaa.gov/publications/coast-pilot/index.html)** is ten volumes of supplemental information important to navigation. PDFs are updated regularly and are free for download.
    
-   **[Historical Maps & Charts Collection](https://historicalcharts.noaa.gov/)** contains over 35,000 images, including some of the nation’s earliest nautical charts.
    

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Did you know?

President Thomas Jefferson founded Coast Survey in 1807 and tasked it with creating charts of the nation's coastal waters so America's young shipping industry could thrive. Reflecting Coast Survey's beginnings, the [Historical Map & Chart Collection](https://historicalcharts.noaa.gov/) contains over 35,000 images — charts, maps, sketches, and more — that are available free to the public. 

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**Last updated:** 11/26/24  
**Author:** NOAA  
[How to cite this article](/about/faq.html)

[Contact Us](/contact.html)

Did you know? - 

- President Thomas Jefferson founded Coast Survey in 1807 and tasked it with creating charts of the nation's coastal waters so America's young shipping industry could thrive. Reflecting Coast Survey's beginnings, the [Historical Map & Chart Collection](https://historicalcharts.noaa.gov/) contains over 35,000 images — charts, maps, sketches, and more — that are available free to the public.
# What is LIDAR

**How is lidar data collected?**

When an airborne laser is pointed at a targeted area on the ground, the beam of light is reflected by the surface it encounters. A sensor records this reflected light to measure a range. When laser ranges are combined with position and orientation data generated from integrated [GPS](/geodesy/gps/) and [Inertial Measurement Unit](http://celebrating200years.noaa.gov/visions/remote_sensing/imu.html) systems, scan angles, and calibration data, the result is a dense, detail-rich group of elevation points, called a "point cloud."

Each point in the point cloud has three-dimensional spatial coordinates (latitude, longitude, and height) that correspond to a particular point on the Earth's surface from which a laser pulse was reflected. The point clouds are used to generate other geospatial products, such as digital elevation models, canopy models, building models, and contours.
# Where is Point Nemo?

![the place in the ocean that is farthest from land](nemo.jpg "Where is Point Nemo?")

_You can't get farther away from land than 'Point Nemo.'_

Want to get away from it all? You can't do better than a point in the Pacific Ocean popularly known as 'Point Nemo,' named after the famous submarine sailor from Jules Verne's _Twenty Thousand Leagues Under the Sea_.

This remote oceanic location is located at coordinates 48°52.6′S 123°23.6′W, about [2,688 kilometers](#) from the nearest land—Ducie Island, part of the Pitcairn Islands, to the north; Motu Nui, one of the Easter Islands, to the northeast; and Maher Island, part of Antarctica, to the south.
# How long is the U.S. shoreline?

![The Miami Beach shoreline.](/facts/shoreline1.jpg)

_The Miami Beach shoreline._

As there is no reference that designates one specific shoreline as the "legal" shoreline, numbers for the length of the U.S. shoreline can vary depending on how the shoreline is defined.

The NOAA shoreline length calculation of 153,646 kilometers (95,471 miles) includes measurements taken in 1930-1940 and 1970. The 1939-40 measurements were determined with a recording instrument on the largest-scale charts and maps available at that time. These measurements included the continental U.S. as well as U.S. territories (Hawaii and Alaska were U.S. territories during this time period). Shorelines of outer coast, offshore islands, sounds, bays, rivers, and creeks were included to the head of the tidewater or to a point where tidal waters narrow to a width of 30.48 meters (100 feet). For the Great Lakes, shoreline lengths were measured in 1970 by the International Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data.

The total length of tidal shoreline includes measurements of the coastal states (which includes the Great Lakes) as well as outlying U.S. territories and possessions.
# What is the cryosphere?

![Beaufort Sea, north of Alaska](/facts/cryosphere.jpg "Beaufort Sea, north of Alaska")

_Beaufort Sea, north of Alaska. One part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic._

There are places on Earth that are so cold that water is frozen solid. These areas of snow or ice, which are subject to temperatures below **0°C** [![32°F](/bs4/img/question.svg)](#) for at least part of the year, compose the cryosphere. The term “cryosphere” comes from the Greek word, “krios,” which means cold.

Ice and snow on land are one part of the cryosphere. This includes the largest parts of the cryosphere, the continental ice sheets found in Greenland and Antarctica, as well as ice caps, glaciers, and areas of snow and permafrost. When continental ice flows out from land and to the sea surface, we get shelf ice.

The other part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic. It also includes frozen rivers and lakes, which mainly occur in polar areas.

The components of the cryosphere play an important role in the Earth’s climate. Snow and ice reflect heat from the sun, helping to regulate our planet’s temperature. Because polar regions are some of the most sensitive to climate shifts, the cryosphere may be one of the first places where scientists are able to identify global changes in climate.
# Why is data on currents important?

## Current data is critical for supporting **safe and efficient** shipping and marine transportation.

![Oceanographers use a variety of tools to monitor currents.](currentdata.jpg "Why is data on currents important?")

The speed and direction of currents can be measured. Oceanographers use a variety of tools, including buoys, to monitor currents.

With predicted, real-time, and forecasted currents, people can safely dock and undock ships, maneuver them in confined waterways, and safely navigate through coastal waters. This helps to avoid ship collisions or delay the arrival of goods.

In addition, current measurements are important for search and rescue operations, environmental disasters, and coastal engineering projects.

When supporting search and rescue operations, understanding the speed and direction of the currents in an area helps to narrow down the rescue and recovery effort. Current prediction information can help scientists clean up after a hazardous oil spill by helping them understand the direction and movement of the oil. Engineers also use currents information to help build marine structures such as bridges or docks and piers.

Current observations are also used to develop and evaluate coastal nowcast or forecast model products that are provided online.
# Is there gold in the ocean?

## Yes, there is gold in the ocean.

![image of a ROV in the water](/facts/gold.jpg "image of a ROV in the water")

If searching for gold, this ROV wouldn't find it. Gold in the ocean is so dilute that its concentration is on the order of parts per trillion. Pictured above, the ROV _Deep Discoverer_ investigates the geomorphology of Block Canyon in the Atlantic Ocean.

Ocean waters do hold gold, but it's difficult to say exactly how much. If you were hoping make your fortune mining the sea, consider this: Gold in the ocean is so dilute that its concentration is very small. One [study](https://www.sciencedirect.com/science/article/pii/0012821X9090060B?via%3Dihub) found there is only about one gram of gold for every 100 million metric tons of ocean water in the Atlantic and north Pacific.

There is also (undissolved) gold in/on the seafloor. The ocean, however, is deep, meaning that gold deposits are a mile or two underwater. And once you reach the ocean floor, you’ll find that gold deposits are also encased in rock that must be mined through. Not easy. Currently, there is no a cost-effective way to mine or extract gold from the ocean to make a profit.
# How is bathymetric data used?

## Accurate bathymetry is essential for **navigation** and **ocean science**.

![A bathymetric image of Lake Huron](/facts/huron.jpg "A bathymetric image of Lake Huron")

_A bathymetric image of Lake Huron. 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._

[Bathymetric data](/facts/bathymetry.html), which includes information about the depths and shapes of underwater terrain, has a range of uses:

-   Nautical charts — These charts, based on bathymetric data, guide mariners the same way road maps guide drivers. Having accurate information about the depth of the water and potential underwater hazards is essential for safe maritime transportation, especially for large ships.
-   Studying [changing coastline features](/observations/monitoring/) — Scientists use bathymetric data to study the effects of climate change and to monitor beach erosion, sea level rise, and subsidence (land sinking).
-   [Hydrodynamic models](https://nauticalcharts.noaa.gov/learn/hydrodynamic-model-development.html) — Bathymetric data is used to create models that can calculate currents, tides, water temperature, and salinity in an area. These models can also be used to predict tides and currents, as well as hazards like coastal flooding and rip tides.
-   Studying marine life — Scientists use bathymetric data to study the habitats of benthic (bottom-dwelling) organisms. Bathymetric maps can help scientists determine where fish and other marine life feed, live, and breed. Bathymetric data is also used to create maps of coral habitats to assist in conservation and monitoring.
# What is VDatum?

![VDatum image of Tampa Bay](/facts/vdatum.jpg "High Resolution digital elevation model of Tampa Bay, Florida.")

_VDatum was used to create this high-resolution Digital Elevation Model of Tampa Bay, Florida. The model merges NOAA hydrographic survey data and topographic data from the U.S. Geological Survey._

VDatum stands for Vertical Datum Transformation, an innovative and evolving software tool under development by NOAA's National Ocean Service. Free to the public, VDatum's primary purpose is to convert elevation data from various sources into a common reference system.

A common reference system is important because irregularities can occur when maps and charts are created from different data sources. In a coastal area, for example, a shift in elevation on a gently sloping beach may change the overall depiction of the shoreline or results of inundation mapping.

VDatum's capabilities to transform and fuse diverse elevation data benefits coastal applications including inundation modeling (e.g., storm surge, tsunami, sea level rise impacts), ecosystem management and coastal planning, hydrographic surveying using Kinematic GPS for vertical referencing, and shoreline delineation from [lidar](/facts/lidar.html) data.

VDatum coverage is complete in all coastal regions of the continental U.S. (including the Great Lakes), Puerto Rico, and the U.S. Virgin Islands. A Southeast Alaska regional model was added in 2019, and future development of coverage for Hawaii, Alaska, and the Pacific territories will commence once foundational geodetic and tidal data are established to allow for valid model construction.

In addition, the current models are being revisited to include additional foundational geodetic and tidal data acquired that will assist in improving transformational components of the VDatum models, assist in refining and validating the uncertainty associated with models, and to support a wider range of applications. The goal is to develop a VDatum utility throughout the country that will foster more effective sharing of elevation data and, eventually, to link such data through national databases.

Did you know? - *Vdatum is available [online](https://vdatum.noaa.gov/welcome.html), as an [API](https://vdatum.noaa.gov/docs/services.html), and as [downloadable software](https://vdatum.noaa.gov/download_agreement.php).*

- [VIDEO: Transforming Heights Between Vertical Datums](https://geodesy.noaa.gov/corbin/class_description/vdatum/)

- [Welcome to VDatum](https://vdatum.noaa.gov/welcome.html)

- [What is the National Spatial Reference System?](https://oceanservice.noaa.gov/facts/nsrs.html)

- [National Geodetic Survey](https://geodesy.noaa.gov)

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# How is ocean observing data used?

## Ocean observing data helps the nation track, predict, manage, and adapt to changes in the marine environment.

![Hurricane damage](coastalobsdata1.jpg "Hurricane damage")

Coastal communities use ocean observing data to prepare for floods and other natural disasters.

NOAA orchestrates the collection of ocean data through a federal, regional, and private-sector partnership called the U.S. Integrated Ocean Observing System, or IOOS®. This system helps the nation track, predict, manage, and adapt to changes in our marine environment.

IOOS data are increasing our understanding of how oceans drive storms to allow meteorologists to develop earlier, more accurate weather predictions. Store managers use these forecasts to decide whether to stock hurricane supplies or beach towels in their stores. Fishermen typically use weather and water data to make informed decisions about when it is safe to head to sea.

Through state-of-the-art high frequency radar systems and other technologies, IOOS scientists can also track ocean currents in near real time. By improving our ability to monitor the speed and direction of surface currents, search and rescue crews can track the probable path of people lost at sea and expedite recovery time.

Surface current maps also support other scientific work including oil spill response, harmful algal bloom monitoring, and water quality assessments. Responders use IOOS data to track oil slicks after a spill because the real-time data shows the movement of the water and therefore the movement of the spill. Data on ocean currents helps forecasters predict both the movement and size of harmful algal blooms, so they can act to decrease health risks to people who might have been affected otherwise.
# What is a guyot?

## A guyot, or seamount, is an undersea mountain.

![A sonar image of a guyot](/facts/guyot.jpg "A sonar image of a guyot")

A sonar image of a guyot, or seamount, in the Arctic. Using a multibeam echo sounder, NOAA scientists can map and produce a visualization from the data collected of the bottom of the ocean.

Guyots support a wide range of organisms, such as this unidentified cnidarian that resembles a Venus flytrap, found on the slopes of the [Davidson Seamount](http://oceanexplorer.noaa.gov/explorations/06davidson/welcome.html).

Seamounts are formed by volcanic activity and can be taller than 10,000 feet. They can be isolated or part of large mountain chains. The New England Seamount contains more than 30 peaks that stretch 994 miles from the coast of New England.

Seamounts often have a high level of biological productivity because they provide habitats for many species of plants and animals. Over 200 species of sea creatures have been observed at a single guyot in the New England Seamount. Seamounts are great locations to discover new species because each seamount houses different types of animals, including many that can only be found in guyot habitats.

Seamounts are home to many commercial fish and are therefore very beneficial to our economy. Seamounts are also important to the field of medicine, as any number of undiscovered species may lead to new drugs or medical treatments.
# Why do we study tides?

## We study tides for safe navigation, recreation, and coastal development.

![Tide station](/facts/tidestudy1.jpg "Tide station")

Tide stations are constructed to measure tides and analyze data so that scientists can predict tides and publish tide tables.

Scientists measure the times, heights, and extents of both the rise and fall of the tidal waters that support a number of different aspects of our daily lives. Navigating ships safely through shallow water ports, intracoastal waterways, and estuaries requires knowledge of the time and height of the tides as well as the speed and direction of the tidal currents. Mariners need accurate data because the depths and widths of the channels along with increased marine traffic leaves very little room for error.

Engineers need data to monitor fluctuating tide levels for harbor engineering projects such as the construction of bridges and docks. Projects involving the construction, demolition, or movement of large structures must be scheduled far in advance if an area experiences wide fluctuations in water levels during its tidal cycle. Habitat restoration projects also require accurate knowledge of tide and current conditions.

Tidal data is also critical to fishing, recreational boating, and surfing. Commercial and recreational fishermen use their knowledge of the tides and tidal currents to help them improve their catches. Depending on the species and water depth in a particular area, fish may concentrate during ebb or flood tidal currents.
# What does the National OCEAN Service have to do with the nation's airports and airspace?

## The National Geodetic Survey's Aeronautical Survey Program, part of the National Ocean Service, provides **highly accurate position, height, and orientation** data needed for **safe air navigation**.

![aerial shot of Aspen, Colorado, airport](/facts/aero-surveys-ngs.jpg "Aerial shot of airport (Aspen, Colorado)")

_This is an airport in Chandler, Arizona, shot from a mounted camera on a NOAA aircraft._

You may be surprised to learn that the National Ocean Service is responsible for surveying and reviewing aeronautical data in support of the nation's airports and airspace.

NOAA has played a role in our nation's aviation industry since the early 1900s. Today, the National Geodetic Survey (part of NOS) administers the Aeronautical Survey Program. This program provides highly accurate position, height, and orientation information needed for safe air navigation.

NGS has been performing aeronautical surveys since the 1920s. More recently, NGS' responsibilities have expanded to reviewing surveys by commercial surveyors to ensure the aeronautical data meets Federal Aviation Administration (FAA) standards and specifications. These surveys provide critical information about airport features and about obstructions and aids to navigation. FAA uses this information to establish airport approach and departure procedures, determine maximum takeoff weights, update aeronautical publications, and conduct airport planning and construction studies.
# What do the numbers mean on a nautical chart?

## Numbers on a nautical chart are **depth measurements**.

![A nautical chart.  image](enc.jpg "A nautical chart")

Soundings, or water depth measurements, are represented by numbers on nautical charts.

Water depths are measured by soundings usually acquired by [hydrographic surveys](/navigation/hydro/). The depths may be in either feet or fathoms (the chart will indicate which). A fathom is a nautical unit of measurement and is equal to six feet.

On a chart, water depths may be 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.

In addition to showing water depths, a nautical chart also tells mariners about  dangers to navigation, aids to navigation, anchorages, and other features. [U.S. Chart No. 1](https://www.nauticalcharts.noaa.gov/publications/us-chart-1.html) explains all the numbers and symbols found on both paper and electronic nautical charts.
# What is the longest mountain range on earth?

## The mid-ocean ridge is the longest mountain range on Earth.

![satellite capture of the mid-ocean ridge](/facts/midoceanridge.jpg "satellite capture of the mid-ocean ridge")

The mid-ocean ridge is visible in this satellite captured, bathymetric data of the western Atlantic Ocean Basin. The mid-ocean range stretches around the globe like the seam of a baseball.

The longest mountain range on Earth is called the mid-ocean ridge. Spanning 40,389 miles around the globe, it's truly a global landmark.

About 90 percent of the mid-ocean ridge system is under the ocean. This system of mountains and valleys criss-crosses the globe, resembling the stitches in a baseball. It's formed by the movement of the Earth's tectonic plates.

As the great plates push apart, mountains and valleys form along the seafloor as magma rises up to fill the gaps. As the Earth's crust spreads, new ocean floor is created. This process literally renews the surface of our planet.

If you look at a map of the world's volcanoes, you'll find that most of them form along the boundaries of this great system. In fact, the global mid-ocean ridge system forms the largest single volcanic feature on the Earth. The mid-ocean ridge consists of thousands of individual volcanoes or volcanic ridge segments which periodically erupt.
# What is a nautical chart?

![nautical chart image](nautical_chart.jpg "What is a nautical chart?")

_NOAA's Office of Coast Survey, part of the National Ocean Service, is the nation's nautical chartmaker._

A nautical chart is one of the most fundamental tools available to the mariner. It is a map that depicts the configuration of the shoreline and seafloor. It provides water depths, locations of dangers to navigation, locations and characteristics of aids to navigation, anchorages, and other features.

The nautical chart is essential for safe navigation. Mariners use charts to plan voyages and navigate ships safely and economically. Federal regulations require most commercial vessels to carry electronic or paper nautical charts while they transit U.S. waters.

Since the mid-1830s, the U.S. Coast Survey (a NOAA predecessor agency) has been the nation’s nautical chartmaker. NOAA's Office of Coast Survey is still responsible for creating and maintaining all charts of U.S. coastal waters, the Great Lakes, and waters surrounding U.S. territories.