DNC® General Information

What is Digital Nautical Chart (DNC®)?
DNC® is a relational, vector-based digital database containing selected maritime features collected and attributed individually to support worldwide marine navigation and geographic information systems (GIS). The database is a digital replication of the feature content of NGA's portfolio of Harbor, Approach, Coastal, and General charts. U.S. chart coverage has been included in the DNC® folio so military systems have a uniform worldwide marine navigation database and weapons systems integration. The existing database consists of data captured from approximately 5,000 charts, which will allow global navigation between 84 degrees North and 81 degrees South. The DNC® database is divided into 29 Geographic Regions and is currently available on CD-ROM and via the NGA Gateway to U.S. military and government agencies. Civil access is through the web as it is planned to eventually phase out CD-ROM distribution of DNC®.

Who is authorized to use DNC®?
U.S. Navy, U.S. Coast Guard, DoD government agencies, and authorized DoD contractors are currently using DNC® for mission planning, situational awareness, research, training, development, and evaluation. DNC® data is authorized for paperless navigation by United States Government vessels on certified systems such as ECDIS-N or comparable systems (33 CFR 164.01). Authorized use is contingent upon the availability and capability of VDU updating the DNC® Geographic Regions. Foreign government vessels not engaged in commerce, with authorized access to DNC® may similarly use DNC® for paperless navigation in U.S. waters.

When will DNC® be available to the public?
DNC® will only be made available to the public for selected continental and US territory waters. All DNC® libraries outside of US waters are not available to the general public due to foreign copyright restrictions.

How can I purchase DNC®?
DNC® is not for sale and is free to anyone who has access and authorization.

How do I acquire DNC® data for non-U.S. waters and CD-ROMs if I am authorized to use of DNC®?
You can download worldwide DNC data with VDU updates through NGA’s other secure websites. While NGA does not distribute CD-ROMs, you can contact Defense Logistics Agency (DLA), Richmond Map Facility either by phone or their website for these requests. If you are a U.S. Government contractor who needs access to DNC®, you should contact your government sponsor for your access needs. DLA can set up one time requests as well as automatic distribution of all updated DNC® and VDU releases.

What data coverage will be available?
Worldwide DNC® data coverage to support paperless navigation is now available for authorized Government vessel navigation on certified systems such as ECDIS-N or comparable systems (33 CFR 164.01).

How many disks on CD-ROM are required for a complete set of DNC®?
29.

Does DNC® meet international ECDIS standards?
Yes, the DNC® meets the functionality and data content requirements of the International Maritime Organization (IMO) and International Hydrographic Organization (IHO) Performance Standards for ECDIS (Electronic Chart Display and Information Systems). DNC® is not produced in the exchange format referenced in the IMO Safety of Life at Sea (SOLAS) convention, i.e., IHO S-57 format. However, the IMO Legal Committee specified that standards and specifications referred to in footnotes, as is the IHO S-57 format standard, are not regarded as mandatory instruments for treaty purposes (LEG 80/10/4, dated 13 August 1999). However, nations implementing an IMO convention are obliged to establish national standards not inferior, or at least equivalent to, those referenced in the IMO convention. ECDIS-N not only incorporates the IMO/IHO Performance Standard; it actually extends it beyond the required functionality. Also, the Vector Product Format (VPF) of DNC® offers more robustness than S-57 data, i.e., more information behind the features/attributes. The S-57 format data does not directly support ECDIS display and must be converted into a display format called the SENC (System Electronic Navigational Chart) and there are several commercial SENC formats. The NGA DNC® was developed as a SENC to maximize interoperability for defense applications. Recently, IHO modified its Performance Standard and Resolutions to make it optional for nations to authorize the conversion of S-57 data into the SENC format on shore rather than onboard ship. DNC® fulfills this IHO option as implemented by the United States.

Is DNC® data copyrighted by NGA?
DNC® is a registered trademark owned by the National Geospatial-Intelligence Agency. NGA supports and respects all foreign copyrights of any proprietary information or data used to compile DNC®. As an original compiler of nautical charts, NGA like any other official Hydrographic Office can acquire certain rights of copyright.

Does DNC® enhance marine navigation and will it replace the paper chart completely?
DNC® will eventually replace paper charts. DNC® is NGA's electronic chart and has been designed to support worldwide naval operations. It offers a revolution in ships' navigation capability and is certainly considered an enhancement to marine navigation. As DNC® libraries are authorized for safe navigation; Navy ships will utilize DNC® on a certified Electronic Chart Display and Information Systems (ECDIS) as the primary means for shipboard navigation. DNC® and ECDIS-N are the greatest advancement in safe navigation since the introduction of radar.

Will the option of using paper charts be available? Will NGA still produce paper charts?
One of the benefits of the DNC® is that a paper chart will eventually be produced from the digital database, thereby reducing associated printing costs. NGA will continue to produce a limited amount of paper charts for as long as there is a valid DoD and USCG requirement for paper products. NGA will gradually phase out traditional paper chart production and transition to alternate methods of satisfying low volume paper chart requirements, e.g., Print on Demand/Remote Replication.

How often will new editions of DNCs be released?
This will be determined by the U.S. Navy and Coast Guard requirements, the amount and extent of new or revised source(s), and world events and government interests.

What is meant by "libraries" of DNC®?
Libraries are the groupings of chart, which are commensurate with NGA's groupings of paper nautical chart scales: Harbor (>1:50,000), Approach (1:25,000 - 1:100.000), Coastal (1:75,000 - 1:500,000) and General (<1:500,000). Each DNC® database contains these four library categories of data along with a browse library that provides a global overview of the DNC® coverage. The libraries have been designed to support various navigation and piloting maneuvers and GIS applications. Approach and Harbor Libraries support navigation in harbors, ports and inshore areas. Coastal Libraries support coastal navigation. General Libraries contain data that supports mission planning and open-ocean navigation.

What are the letters and numbers on a library name?
The first letter on the library name denotes the type of library (i.e. A=approach, C=coastal, H=harbor and G=general). The next two digits denote the geographic area. The remaining numbers denote the world port index. Example Library A1707300 is an approach for DNCDX017, with World Port Index 07300.