ELECTRONIC NAVIGATIONAL CHART FAQ
1.What is an Electronic Navigational Chart?
2. What are ECS and ECDIS?
3. What data coverage will be available?
4. How will the public be able to obtain NOAA ENC®s?
5. How much does an NOAA ENC® cost?
6. Is an NOAA ENC® a simply a copy of the paper chart?
7. What are the sources used in compiling NOAA ENC®s?
8. Does the NOAA ENC® have all of the features from the chart?
9. What NOAA ENC® data is currently available?
10. How current is the NOAA ENC®?
11. Is NOAA ENC® data copyrighted by NOAA?
12. Do NOAA ENC®s enhance marine navigation and will they replace the paper chart completely?
13. How often will new editions of NOAA ENC®s be released?
14. What is meant by an NOAA ENC® "cell"?
15. On what media will NOAA ENC®s be available?
16. What hardware and software is required operate NOAA ENC®s?
17. Can commercial systems operate and view NOAA ENC® data?
18. Will NOAA provide any viewing or navigation software?
19. What commercially available software can be used to view NOAA ENC®s?
20. What are the uses of NOAA ENC®s?
21. What are the benefits of using NOAA ENC®s?
22. What capabilities does NOAA ENC® provide that are not available in a paper or raster chart?
23. How is the data displayed?
24. Does the data look like a paper chart?
25. Will NOAA ENC®s be updated via the U.S. Coast Guard Local Notice to Mariners?
26. Can a user get a screen print of any displays?
27. Can a display be used without GPS input?
28. On a ship that transits from one NOAA ENC® to another NOAA ENC®, can both areas be simultaneously shown in a single display?
29. Can other ships navigating in the ships area also appear in the NOAA ENC® display?
30. How will NOAA ENC®s be updated and maintained?
31. What does the date entry mean on the NOAA ENC® download page?
32.Do NOAA ENC®s have edition numbers or print dates like paper charts?
33. What does the file name of the NOAA ENC® mean?
34. What is the CATALOG.031 file?
35. What are the other files included with the NOAA ENC®?
36. Is the NOAA ENC® a Windows only product?
37. What is the difference between the NOAA ENC® and the National Imagery and Mapping Agency Digital Nautical Chart (NIMA DNC™)?
1. Question - What is an Electronic Navigational Chart?
Answer -ENCs are vector charts that conform to IHO specifications, as contained in Publication S-57. They are compiled from a database of individual items ('objects of digitised chart data which can be displayed as a seamless chart. The NOAA ENC® is intended for use in electronic charting systems (ECS) as well as Electronic Chart Display and Information Systems (ECDIS). When used in an ECDIS or some ECS, the data can be reassembled to display either an entire chart image or a user-selected combination of chart data. ENCs are "intelligent" in that systems using them can be programmed to give warning of impending danger in relation to charted information and the vessel's position and movement. NOAA ENC®s can also be used in geographic information systems (GIS) as base map data. (Back to top)
2. Question - What are ECS and ECDIS?
Answer - Electronic chart systems encompasses any electronic system that uses digital chart data. The chart data can be vector or raster and no specific format is currently defined, although many ECS can use NOAA ENC® data. There are standards being developed for ECS by the Radio Technical Commission for Maritime Services (RTCM www.rtcm.org). Electronic Chart Display and Information Systems (ECDIS) are systems that are certified to meet a suite of international standards: IHO (http://www.iho-ohi.net/english/home/) Transfer Standard for Digital Hydrographic Data S- 57, IHO Specifications for Chart Content and Display aspects of ECDIS S- 52, IMO (www.imo.org) MSC.232 (82) Performance Standards for ECDIS, and IEC (www.iec.ch) 61174: ECDIS - Operational and performance requirements, methods of testing and required test results. An ECDIS must use "official" NOAA ENC® data to meet all of these standards and may use "official" raster data where NOAA ENC® data is not yet available. (Back to top)
3. Question - What data coverage will be available?
Answer – As of September, 2008, all of the major ports throughout the country now have NOAA ENC coverage. Many smaller scales coastal ENCs that connect these ports have been completed, while some are still in the building process. NOAA plans to continue its ENC building program in the upcoming years. (Back to top)
4. Question - How will the public be able to obtain NOAA ENC®s?
Answer - NOAA ENC®s will be available for download from the Coast Survey Website (nauticalcharts.noaa.gov). (Back to top)
5. Question - How much does an NOAA ENC® cost?
Answer - NOAA ENC®s downloaded directly from the Coast Survey Website are available free of charge. Private companies may offer NOAA ENC®s as part of a service, in which case there may be an associated charge. (Back to top)
6. Question - Is an NOAA ENC® a simply a copy of the paper chart?
Answer - The NOAA ENC® program is building the NOAA ENC® production database from a combination of charted information as well as original "source" information. NOAA has compiled critical features such as channel limits, aids to navigation and obstructions from the original documents that were used to put the feature on the paper chart. This means that a feature such as a federally maintained channel was digitized from a 1:2,400 scale drawing as opposed to a 1:20,000 scale chart. The objective is to use more accurate information for features that are critical to the safety of navigation. (Back to top)
7. Question - What are the sources used in compiling NOAA ENC®s?
Answer - NOAA uses a number of sources in compiling NOAA ENC®s. These include: U.S. Army Corps of Engineers surveys, drawings and permits, U.S. Coast Guard Local Notices to Mariners, National Imagery and Mapping Agency Notices to Mariners, NOAA hydrographic surveys, the largest scale paper chart of the area, as well as other source material that comes in to NOAA from a variety of public and private sources. (Back to top)
8. Question - Does the NOAA ENC® have all of the features from the chart?
Answer - The NOAA ENC® contains most of the features currently shown on the corresponding paper chart. The detailed road networks and depictions of buildings in urban areas have been replaced with an "urban area" that is displayed as a tinted area with the associated place name. (Back to top)
9. Question - What NOAA ENC® data is currently available?
Answer - Approximately 100 NOAA ENC®s are available for evaluation, familiarization, testing and software development from the Coast Survey Website (nauticalcharts.noaa.gov). (Back to top)
10. Question - How current is the NOAA ENC®?
Answer - All NOAA ENC®s are maintained for Notices to Mariners, and updates are released weekly. (Back to top)
11. Question - Is NOAA ENC® data copyrighted by NOAA?
Answer - No. (Back to top)
12. Question - Do NOAA ENC®s enhance marine navigation and will they replace the paper chart completely?
Answer - NOAA ENC®s and RNCs will eventually replace paper charts for vessels using electronic navigation. NOAA will continue to produce paper charts for those users who do not choose to use electronic navigation. NOAA ENC®s and ECDIS are the greatest advancement in maritime safety since the introduction of radar to ships.(Back to top)
13. Question - How often will new editions of NOAA ENC®s be released?
Answer - This is yet to be determined. In paper chart production, new editions are driven by the amount of new information to be applied to the chart as well as how many copies are in stock for use. Neither of these considerations really apply to the NOAA ENC®, so new NOAA ENC® editions may be synchronized to the paper chart cycle or may be on a set schedule, e.g., annually released. (Back to top)
14. Question - What is meant by an NOAA ENC® "cell"?
Answer - The area covered by an NOAA ENC® is referred to as a "cell." At present, each NOAA ENC® corresponds to the largest scale paper chart in a given area. As the NOAA ENC® begins to contain more detail and the file sizes get larger, it may become necessary to split the cells into smaller areas. (Back to top)
15. Question - On what media will NOAA ENC®s be available?
Answer - Coast Survey does not provide NOAA ENC®s on any hard media, they are only available from the Government at the Coast Survey Website (nauticalcharts.noaa.gov). However, private companies may make NOAA ENC®s available on products that are available on hard media. (Back to top)
16. Question - What hardware and software is required operate NOAA ENC®s?
Answer - Display of and NOAA ENC® is dependent on navigation software such as an ECDIS. However, the NOAA ENC® is not dependent on unique operating systems or navigation software. Since it is provided in an international, publicly available standard format, any software company that wants to support NOAA ENC® data can implement that capability without restricting the software to a proprietary format or provider. (Back to top)
17. Question - Can commercial systems operate and view NOAA ENC® data?
Answer - Yes. A number of commercially available systems use NOAA ENC® data. These include both "type- approved" ECDIS software as well as ECS packages. (Back to top)
18. Question - Will NOAA provide any viewing or navigation software?
Answer - No. NOAA is providing the NOAA ENC® data. It is up to the commercial market to provide software to use it. (Back to top)
19. Question - What commercially available software can be used to view NOAA ENC®s?
Answer - Please look at the list of software provided on the NOAA ENC® Homepage. (Back to top)
20. Question - What are the uses of NOAA ENC®s?
Answer - Marine navigation, route planning, and GIS applications are just some the uses for the data as a background display. USCG already uses NOAA ENC® in several Vessel Traffic Systems (VTS) to monitor ship movements in rivers, harbor, and bays in the U.S. Since NOAA ENC® is a vector product, categories of data may be individually selected or queried. Because of this data flexibility, NOAA ENC® is a powerful database supporting various marine and GIS applications. (Back to top)
21. Question - What are the benefits of using NOAA ENC®s?
Answer - Incorporating digital chart data with a continuous GPS signal for automated vessel positioning enhances safety of navigation. Users can selectively display only the information desired while the computer can continue to process all the information for safety of navigation. Many marine mishaps are due to human error. Vector chart data with proper software applications will enhance safe navigation and provide the mariner with advance electronic warnings of unforeseen dangers. (Back to top)
22. Question - What capabilities does NOAA ENC® provide that are not available in a paper or raster chart?
Answer - Data can be queried (i.e., vector data is smart data) in a variety of ways, which gives the user much more information than a static paper chart can. The navigator can control the display of the NOAA ENC® data, which allows for a customized display that only shows information critical to safe navigation. The navigation system software can continuously monitor the ship's position relative to all of the features contained in the NOAA ENC®, whether displayed or not, and sound alarms if it detects a hazardous situation. Similarly, the software can check that planned routes will provide safe passage for the vessel by checking for proximity to dangers and crossing areas with insufficient depth. (Back to top)
23. Question - How is the data displayed?
Answer - This depends entirely on the navigation software or GIS that is being used. An ECDIS will use the symbols and colors required by the IHO S-52 International Standard, but other systems can use whatever symbols the manufacturer chooses. (Back to top)
24. Question - Does the data look like a paper chart?
Answer - It can, depending on what colors and symbols the display software is using. (Back to top)
25. Question - Will NOAA ENC®s be updated via the U.S. Coast Guard Local Notice to Mariners?
Answer - Yes. NOAA provides updates for the NOAA ENC® similar to the updates currently provided for the raster chart. These will include all Local Notices to Mariners corrections. (Back to top)
26. Question - Can a user get a screen print of any displays?
Answer - Depends on the software being used. Most PC platforms support screen prints. (Back to top)
27. Question - Can a display be used without GPS input?
Answer - Yes, but the ideal navigational situation is to have an automated positioning signal feed into the system displaying NOAA ENC® data for continuous vessel tracking. (Back to top)
28. Question - On a ship that transits from one NOAA ENC® to another NOAA ENC®, can both areas be simultaneously shown in a single display?
Answer - It all depends on the customer's system capability; nothing in the database precludes this capability. (Back to top)
29. Question - Can other ships navigating in the ships area also appear in the NOAA ENC® display?
Answer - This depends on the customer electronic navigation systems - nothing in the data precludes display of the data from ship's radar screen or, when adopted, Automated Information System symbology. (Back to top)
30. Question - How will NOAA ENC®s be updated and maintained?
Answer - NOAA ENC®s are updated with new source material and Notices to Mariners (both Local and NIMA). The NOAA ENC® production system is able to convert any new source materials such as hydrographic surveys, Notices to Mariners, etc. for inclusion in the NOAA ENC® database. (Back to top)
31. Question - What does the date entry mean on the NOAA ENC® download page?
Answer - The date shown on the NOAA ENC® download page is the date that the compressed NOAA ENC® archive was last modified. This usually means that a new, updated cell replaced the NOAA ENC® cell file. It may also mean that one or more of the supporting text or picture files was modified. Users should always make sure that they are using the latest version of the NOAA ENC® and its supporting files. (Back to top)
32. Question - Do NOAA ENC®s have edition numbers or print dates like paper charts?
Answer - In short, yes they do. Every NOAA ENC® starts with a file header that has various information, metadata, about that particular NOAA ENC®. The header has a number of "subfields," each of which has information about a particular aspect of the NOAA ENC®. One subfield is the edition number, which is a sequential number that works just like the edition number on a paper chart. The first time an NOAA ENC® is issued, it is edition one (1), which is subsequently superseded by edition two (2) and so forth. There is also a subfield called issue date which is the first date that the NOAA ENC® may be used for navigation. Finally, the update application date subfield indicates the last date through which an update was available for use (Notices to Mariners in particular). (Back to top)
33. Question - What does the file name of the NOAA ENC® mean?
Answer - The NOAA ENC® file name format is specified in the IHO S-57 standard. The first two characters, US, indicate that the U.S. Office of Coast Survey, NOAA, produced the NOAA ENC®. The third character indicates the "navigational purpose" of the NOAA ENC® as defined in S-57, a rough indicator of the scale of the NOAA ENC®: 1-overview; 2-general; 3-coastal; 4-approach; 5-harbor; 6-berthing. The remaining characters left of the dot are defined by Coast Survey. The fourth and fifth characters are the two letter postal code for the state where the NOAA ENC® is located (e.g., TX for Texas, NY for New York, etc.) The next two characters are the NOAA ENC®s number and the final character is "M" indicated that the NOAA ENC® is in metric units. The file extension, ".000," for a base NOAA ENC® cell is used for updating. The first update for a cell will be ".001" the next ".002" and so forth. (Back to top)
34. Question - What is the CATALOG.031 file?
Answer - The CATALOG.031 file is a listing of the cells and ancillary files that are included in an NOAA ENC® "exchange set." Each file has an entry in the CATALOG file so that your software can check to see if all of the relevant files are included. The ".031" extension indicates the edition of S-57 that was used to produce the files. (Back to top)
35. Question - What are the other files included with the NOAA ENC®?
Answer - Besides the CATALOG file explained above, there is a README.TXT file included that lists all of the NOAA ENC®s with their corresponding paper/raster chart number, title and other information. Each NOAA ENC® may have ancillary files associated with it. These may be text files that are analogous to chart notes on the paper chart or possibly information from the Coast Pilot. There also may be picture files such as .tif or .jpg files that include a picture that is linked to a feature(s) on the NOAA ENC®, such as a picture of a bridge. (Back to top)
36. Question - Is the NOAA ENC® a Windows only product?
Answer - In short, no. The NOAA ENC® uses the international standard format for vector electronic charts, the International Hydrographic Organization "Transfer Standard for Digital Hydrographic Data, Special Publication S-57." The file format used by the S-57 standard is ISO/IEC 8211, "Information processing - Specification for a data descriptive file for information interchange." This format is designed to be platform and operating system independent and the data files can be used with operating systems such as Windows, Macintosh, UNIX and Linux. However, since the NOAA ENC® is a file of data, a computer needs an application program that is capable of reading the ENC implementation of the 8211 files structure. (Back to top)
37. Question - What is the difference between the NOAA ENC® and the National Imagery and Mapping Agency Digital Nautical Chart (NIMA DNC™)?
Answer - 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 an Electronic Chart Display and Information System. The DNC™ uses the Vector Product Format, which is a NATO standard for digital military map and chart data. They are both vector format charts and are based on NOAA nautical charts, just in different formats. The NOAA ENC®, however, has certain critical features such as aids to navigation and channel limits created from larger scale, more accurate information than can be obtained by digitizing a paper or raster nautical chart. (Back to top) |
