NOAA
Office of Coast Survey
National Oceanic and Atmospheric Administration
U.S. Department of Commerce

FAQ

How can I get a job at NOAA?

Coast Survey advertises open federal positions on the USAJobs.gov website. For more information, see our Employment and Internship Opportunities webpage.

How can I report a problem with a nautical chart?

You can report problems with nautical charts though Coast Survey's online ASSIST stakeholder engagement and feedback tool or by calling
1-888-990-6622.

Who can I contact if I have a question or comment about a nautical chart?

You can submit questions or comments through Coast Survey's online ASSIST stakeholder engagement and feedback tool or by calling
1-888-990-6622.

What is a nautical chart?

A nautical chart is a two-dimensional graphic of a 3-D world. It represents part of the spherical earth on a plane surface. It shows water depth, the shoreline of adjacent land, prominent topographic features, aids to navigation, and other navigational information.

The navigator uses the chart to plot courses, ascertain positions, and view the relationship of the ship to the surrounding area. It helps the navigator avoid dangers and arrive safely at the desired destination.

What is the difference between a map and a chart?

A nautical chart presents the coastline taking into account varying tidal levels and water forms. A map, on the other hand, emphasizes landforms.

Where can I learn more about the different symbols on a nautical chart?

U.S. Chart No. 1 describes the symbols, abbreviations and terms used on all NOAA, NGA and international nautical charts, as well as the symbols used to portray NOAA ENC® charts on an ECDIS.

What is the difference between an ENC and an RNC?

A raster navigational chart (RNC) is a digital image of the corresponding NOAA paper nautical chart. The information is stored as raster data - rows and columns of color pixels. The pattern of the colored pixels gives shape to the individual features on the chart.

An electronic navigational chart (ENC) is a digital chart database stored as vector data - pairs of coordinates that define the position and shape of points, lines, and area features.

There are many other important differences. See the RNC - ENC Comparison page for more information.

How can I find out which chart I need?

Visit the NOAA Chart Locator to find paper nautical charts and electronic navigational charts (ENCs). The locator can also be used to identify the appropriate Coast Pilot volume to use in a particular area.

Why do I need an updated chart?

Coast Survey cartographers apply thousands of changes to NOAA charts every year. Some changes are minor, but many are critical to safe navigation. Those critical updates can include new shoals, wrecks, and obstructions, and the latest changes to navigation aids. Additionally, shorelines are changing all the time, due to natural forces, storms or infrastructure improvements.

questionWhere do I get chart updates?

The United States Coast Guard issues Local Notices to Mariners, providing up-to-date important navigational information. The National Geospatial - Intelligence Agency issues weekly the U.S. Notices to Mariners for larger vessels, such as those operating in 12 feet of water or more. You can also find information about chart corrections on NOAA’s Weekly Chart Update webpage.

Where can I get a paper chart?

Paper nautical charts can be purchased from a NOAA certified chart agent. It is easy to order a chart online or by telephone and have the chart delivered to your door.

How can I be sure that I have an official NOAA chart?

NOAA certified nautical charts and other nautical products meeting U.S. Coast Guard carriage requirements are available from the following sources:

How can I become a NOAA certified chart agent?

See our Business and Partnership Opportunities page for information about becoming a NOAA - certified agent.

How can I print a chart at home?

Use the NOAA Chart Locator to find the chart that you are interested in. Then look under the "Available Products" section of the Map Selection Information panel on the right side of the Chart Locator window. Click the "PDF" button to download a full-size nautical chart or click the "BC" button to download an 8.5" x 11” BookletChart™ to your computer. Full-size PDFs can be printed on a large format plotter; BookletCharts can be printed on an ordinary home or office color printer.

How can I get a copy of an old NOAA chart?

NOAA’s Historical Map & Chart Collection contains over 35,000 images - charts, maps, sketches, and more - that are available free to the public.

Are there copyright restrictions for printing a chart, using it in a publication, or repackaging chart images to create new products?

NOAA’s nautical charts are in the public domain. You may use then for any purpose free of charge, with two exceptions:

  1. Paper charts that fulfill chart carriage requirements for regulated commercial vessels under Titles 33 and 46 of the Code of Federal Regulations must be purchased from NOAA-certified vendors.
  2. Commercial printers must be certified by NOAA to sell navigational charts and publications that are “published by the National Ocean Service.” Information on becoming a certified chart distributor can be found on our Business and Partnerships Opportunities webpage.

When republishing a NOAA chart or a portion of a chart image, we request the citation, "Provided by NOAA Office of Coast Survey, nauticalcharts.noaa.gov” be used, although this is not required. More information on how copyrights apply to government publications can be found at U.S. Government Works.

What is an electronic navigational chart?

Electronic navigational charts (ENC) are vector data sets that support all types of marine navigation. More information can be found on our NOAA ENC® webpage.

What are ECS and ECDIS?

Electronic chart systems (ECS) encompass many electronic systems that display digital chart data. The chart data can be vector or raster. No specific format is currently defined, although many ECS can use NOAA ENC data. The Radio Technical Commission for Maritime Services (RTCM) has published Standard for Electronic Chart Systems, RTCM 10900.6. The USCG now allows most commercial vessels on domestic voyages to use an ECS with NOAA ENCs for navigation without paper charts.

Use of an Electronic chart display and information system (ECDIS) with ENC data is required for large commercial vessels on international voyages. ECDIS are certified to comply with several international standards, some of which are listed below.

  • IHO Transfer Standard for Digital Hydrographic Data, IHO S-57
  • IHO Specifications for Chart Content and Display aspects of ECDIS, IHO S- 52
  • IMO Performance Standards for ECDIS, MSC.232(82)
  • ECDIS - Operational and performance requirements, methods of testing and required test results, IEC 61174

How can I obtain NOAA ENCs?

You can download individual NOAA ENCs from the NOAA Chart Locator or by region from the ENC download page. NOAA ENCs downloaded directly from the Coast Survey website are free.

NOAA ENCs may also be obtained from NOAA certified ENC distributors who provide global ENC distribution services. These companies may charge a fee for this service.

Is a NOAA ENC simply a copy of the paper chart?

The sources used to compile and maintain paper charts and ENCs are the same, but a paper chart is a static representation, while an ENC has layers of data that can be turned on and off in the chart display and interact with the navigation system to provide warnings and alarms of dangers. The display of ENCs is also often simpler and less cluttered than the portrayal rendered on a paper chart.

What are the sources of data used to compile NOAA ENCs and paper nautical charts?

NOAA obtains data from a number of sources. The primary ones are water depths and the identification of wrecks, rocks, and other obstructions – from NOAA’s Hydrographic Surveys Division; depths within federally maintained channels – from the U.S. Army Corps of Engineers; delineation of shoreline – from NOAA’s National Geodetic Survey; positions, types, and characteristics of aids to navigation (buoys, beacons, and navigational lights) – from the U.S. Coast Guard. More information is available on the Chart Source Data webpage.

How current is the NOAA ENC?

All NOAA ENCs are under continuous maintenance. As new source data is received by NOAA, it is evaluated, compiled, and released to the public on a weekly basis. This includes relevant USCG Local Notice to Mariners and NGA Notice to Mariners.

Do ENCs meet U.S. Coast Guard carriage requirements?

Official NOAA ENCs meet U.S. Coast Guard carriage requirements, as defined in Title 33 and Title 46 of the U.S. Code of Federal Regulations (CFR), and as specified in USCG Navigational and Vessel Inspection Circular No. 01-16 (NVIC 01-16).

What hardware and software is required operate NOAA ENCs?

Display of NOAA ENC depends on navigation software such as an ECDIS, which conforms to international standards. However, the NOAA ENC is not dependent on unique operating systems or navigation software. Since it is provided in a standard format, any navigation software company that wants to support NOAA ENC data can create applications that use it.

Does NOAA provide any viewing software?

You can see a seamless display of NOAA ENCs with the NOAA ENC® viewer. However, this online chart display and images captured from it are not suitable to be used for navigation.

What does the date entry mean on the NOAA ENC download page?

Each ENC has an Update Application Date, an Issue Date and various Cleared Dates. For more information, see the ENC Dates webpage.

Do NOAA ENCs have edition numbers or print dates like paper charts?

Yes. Every NOAA ENC starts with a file header that contains information about that particular ENC, including edition number, issue date, and update application date.

What are the other files included with the NOAA ENC?

  • CATALOG.031 - lists of the cells and ancillary files that are included in an NOAA ENC "exchange set."
  •  
  • README.TXT - lists all of the NOAA ENCs with their corresponding paper/raster chart number, title and other information.
  •  
  • Ancillary files - text files that are analogous to chart notes on the paper chart or possibly information from the United States Coast Pilot.
  •  
  • Image files - a picture that links to a feature(s) on the NOAA ENC, such as a picture of a bridge.

What is the difference between the NOAA ENC and the Digital Nautical Chart (DNC™)?

They are both vector format charts. However, the NOAA ENC is based on the International Hydrographic Organization Transfer Standard for Digital Hydrographic Data, Publication S-57 and is approved by the International Maritime Organization for SOLAS class vessels to use for navigation in ECDIS. The DNC is based on the Vector Product Format Standard, which is a NATO standard for digital military map and chart data. More information about DNCs can be found at the National Geospatial-Intelligence Agency website.

How do paper charts and RNCs compare?

The paper nautical chart is the fundamental tool of marine navigation. It has served for hundreds of years to convey information about the marine environment and for voyage planning and monitoring.

The NOAA RNC® exactly reproduces the familiar paper chart image in a digital, raster format.

Can text and symbols be resized (rescaled) when one zooms in and out on a raster chart?

No. Text and symbols will be enlarged or reduced as one zooms in and out. If this results in text that is too small or too large to read, it means that you are operating out-of-scale and should switch to a different scale chart.

Can the mariner limit the information that is displayed on an RNC?

No. Only the entire RNC chart image can be displayed, unlike ENCs, in which certain layers of information may be turned on or off.

See the RNC - ENC Comparison webpage for more information on the difference between these products.

Can data be interrogated with RNCs as it can with ENCs in an ECDIS?

No. RNCs cannot be interrogated. An RNC is merely an electronic picture of a paper chart. However, since the RNC displays all of the paper chart, most information is already displayed and the RNC does not need to be interrogated.

Do NOAA RNCs have daytime and nighttime colors like ENCs in ECDIS?

No, NOAA has specified only one color pallet for RNCs, which is similar, but not exactly the same, as the colors seem on NOAA paper charts.

I downloaded RNCs to my local computer. When I double click on the file and nothing happens. Why?

RNCs are created in a specific international format, which cannot be displayed with the ordinary text or image processing software found on most computers. There are many RNC display software packages available commercially. NOAA does not create of distribute software to display its RNC or ENC products.

What is hydrography?

The International Hydrographic Organization defines hydrography as “the branch of applied science which deals with the measurement and description of the physical features of the navigable portion of the earth’s surface [seas] and adjoining coastal areas, with special reference to their use for the purpose of navigation.”

What is the purpose of a hydrographic survey?

A hydrographic survey supports a variety of activities: nautical charting, port and harbor maintenance (dredging), coastal engineering (beach erosion and replenishment studies), coastal zone management, and offshore resource development. Hydrographers use sound (SONAR) and light (LIDAR) to ‘see’ the bottom of the ocean. The primary information obtained by hydrographic surveys are water depth and potential existence of dangers to navigation. A hydrographic survey also helps determine the nature of the sea floor material (i.e. sand, mud, rock), which is important for anchoring, dredging, structure construction planning, pipeline and cable routing, and fisheries habitat mapping.

Where can I find bathymetric and hydrographic data?

National Ocean Service hydrographic and bathymetric data is available from the National Centers for Environmental Information (NCEI).

Where can I find information on submerged wrecks and obstructions?

Information for submerged wrecks and obstructions in the coastal waters of the United States, including geographic coordinates, can be obtained from NOAA’s Automated Wreck and Obstruction Information System (AWOIS). AWOIS contains supplemental textual information including coordinates for items of navigational significance charted on NOAA nautical charts but is not designed to be a comprehensive list of all shipwrecks in any given area. Note: AWOIS data is no longer updated by NOAA. It is provided for informational purposes only and is not an authoritative source of information.

Where will NOAA be surveying this year?

Information about NOAA’s survey plans can be found on our Current Year Survey Plans webpage.

Where can I find hydrographic and bathymetric information for inland lakes and rivers?

NOAA's Office of Coast Survey primarily surveys U.S. coastal waters. The U.S. Geological Survey and the U.S. Army Corps of Engineers survey inland rivers and waters.

Where can I find information on tides and currents?

NOAA's Center for Operational Oceanographic Products and Services predicts and measures tides, water levels, and currents.

Where can I find topographic sheets (T-sheets) or shoreline information?

Shoreline information and data is available from NOAA's Office for Coastal Management and the National Geodetic Survey.

Revised: 6/14/2019