NOAA ENC^® ‐ Electronic Navigational Charts

What are ENCs?

Electronic Navigational Charts (ENC) are vector data sets that support all types of marine navigation. Originally designed for large commercial vessels using a sophisticated navigational computer called an Electronic Chart Display and Information System (ECDIS), ENCs are now also being used on simpler electronic chart systems and "chart plotters" on many types of ships and by recreational boaters. NOAA ENCs help provide real-time ship positioning, as well as collision and grounding avoidance.

Each ENC, also known as a cell, is a digital database that stores the location and shape of charted features as pairs of latitude and longitude coordinates. Originally designed for large commercial vessels that use a sophisticated navigational computer called an Electronic Chart Display and Information System, or ECDIS, ENCs are now also being used on simpler electronic chart systems and chart plotters on many types of ships and by recreational boaters.

ENC database records hold detailed information about every feature compiled on the chart, such as its location, color, shape, height or depth, purpose, quality of position, and other attributes. Electronic navigation systems use this information to portray the chart content on a map display, as well as to initiate warnings and alarms when a ship is heading into shallow water or toward other dangers to navigation.

NOAA ENCs comply with standards set forth by the International Hydrographic Organization. ENC data is produced by scores of other countries and used by mariners around the world. NOAA maintains thousands of ENCs over U.S. coastal waters and the Great Lakes. The U.S. Army Corps of Engineers produces a similar product, called the Inland ENC, or IENC for many U.S. rivers.

Individual NOAA ENCs may be downloaded from the NOAA Chart Locator or in groups by region from the ENC download page. NOAA ENCs downloaded directly from these Coast Survey websites are free. NOAA ENCs may also be obtained from the International Centre for Electronic Navigational Charts, or IC-ENC through a value added reseller. IC-ENC charges a fee for this service.

Updates for ENCs

NOAA continually updates ENCs with data from a variety of sources and new ENC update cells are uploaded every weekday evening. Updates include critical changes, such as changes to aids to navigation (buoys, beacons and lights) or newly discovered shoals; as well as the routine addition of newly compiled data, such as hydrographic or shoreline surveys. The NOAA Navigation Updates page shows where changes have occurred.

ENC Derived Paper Charts

The NOAA Custom Chart application enables users to create their own customized charts directly from the latest NOAA ENC data. These charts contain all the same information as ENCs, but it is presented using the same symbols and colors used on traditional paper nautical charts.

ENC Data for GIS

NOAA ENC data is also available as online display services and for download in geographic information systems, or GIS, compatible formats. This enables the use of ENC data as a base map for a variety of purposes, such as coastal management or emergency response command centers. More information is on the GIS Data & Services webpage.