Electronic Chart Display and Information System - Essay Example

Electronic Chart Display and Information System (ECDIS Summary Electronic Chart Display and Information System (ECDIS) has been in vogue in shipping industry for about two decades now. Electronic chart presentation is only one aspect of ECDIS. ECDIS is also an information system. ECDIS represents an item of equipment consisting of hardware, software and the data. This original data is also called electronic nautical chart (ENC).The data in the System Electronic Nautical Chart (SENC) is generated from the original data of the ENC. The data is crucial for ECDIS deployment. The official data for the electronic nautical charts are published by the national Hydrographic Offices (HOs) of the maritime nations, as is the case for the paper nautical charts. Data supply is still a weak point of ECDIS at present. The hydrographical services are public authorities, who have now to switch from production of paper nautical charts to digital ECDIS data. Raster data is provided by official sources and fills the gaps in ECDIS data. The scanned paper charts cannot provide any real alternative to ECDIS data. The International Hydrographic Office (IHO) has the responsibility for standardizing the digital chart objects for ECDIS. Chart data comes without geographic projection, only with coordinates. : Electronic Chart Display and Information System (ECDIS): Its Benefits to Marine Navigation and Safety Introduction Electronic Chart Display and Information System (ECDIS) has been in vogue in shipping industry for over two decades now. ECDIS, however, can have a much wider application than in shipping, because electronic display and information can be used in aviation charts, street maps, railway maps, etc. In all these and other likewise segments of transport and communication, electronic display and information can be presented on a computer using the same methodology. However it is in shipping that the system is widely used and we shall restrict our discussion to the electronic nautical charts.Moreover ECDIS was initially developed for shipping, and it is in that industry that its use is wide-spread and likely to increase manifold in the future.. Electronic chart presentation is only one aspect of ECDIS. ECDIS is also an information system. As an information system, ECDIS enables the user to access additional information on the items displayed in the graphics presentation; for instance, about a lighthouse. This may be marked on the chart by a tower symbol. The system can give further information on this object, for example, about its appearance, structure, and its current status, that is, for instance, it used to be operational once, but is no longer so, and is now preserved as a monument. The data may enable one to access, if required, further data about a detailed history of the lighthouse and view a digitalised photo of this object. The quantum and quality of the information available on the individual objects depends on how up-to-date, accurate and well maintained the data base is, not on the ECDIS itself. ECDIS stores these various details in a geographic-object oriented data base, so that ECDIS can be said to belong to the group of Geographic Information Systems (GIS). The parts of ECDIS computer For the user, who is the navigator, ECDIS is only one item of equipment among many on the bridge of a modern ship. Operating the ECDIS is not the main duty of a ship's officer. Rather, the system replaces the conventional chart table and is intended to make all types of work traditionally connected with the paper nautical chart easier, more precise and faster. These include route planning, entry of observations, instructions and notes, position determination and updating charts with the aid of the Notices to Mariners (NtM). ECDIS represents an item of equipment consisting of hardware, software and the data. The hardware of the ECDIS is a computer with graphics capability, a high performance PC or a graphics workstation installed in a console linked with other items of ship's equipment. Thus, ECDIS obtains the course from the gyro compass, the rate of turn from the turn indicator, and the ship's speed through water from the log (the ship's "speedometer"). Important features are the links with the position sensors of the ship (Decca, Loran, transit satellite navigation system) and in particular with the GPS (global positioning system, a satellite based positioning system), supplying via the NMEA interface a constant stream of highly precise position data (NMEA National Marine Electronics Association; NMEA0183 Standard for Interfacing Marine Electronic Devices, data record). Even radar pictures can be superimposed, either as raw data from rasterscan radar, or as synthetic ARPA (automatic radar plotting aid) radar information. The software that makes the computer an ECDIS consists of the user interface (UI) and 'the ECDIS kernel', the software that makes it possible to read the data and display a chart. This software is also called 'function library', for, in addition to the chart picture, the user interface shows buttons and keys for operating the nautical chart. The data The official original data (S57 data), also called electronic nautical chart (ENC) is usually supplied on CD-ROM or, in case of updates, via digital telephone or satellite communication system. The chart database is organized in cells that cover the entire earth's surface without overlapping. The cells store all nautical chart objects as well as objects created only during the operation of the system, such as 'waypoints and leg lines', notes, positions of own ship and of other vessels, etc. The System Electronic Nautical Chart (SENC) data is generated from the original data of the ENC. The ENC has to be kept unaltered in order to be able to reconstruct the SENC data if this is unintentionally damaged or destroyed. In SENC, the chart data is stored in a proprietary file format designed by the ECDIS manufacturer for speed and reliability. The original S57 data represents a specific kind of 'attributed vector data', (object description with geometry and geographical position) which requires an efficient kind of storage. For compactness and speed, vector data is the optimal solution in contrast to the voluminous raster data. The data is crucial for ECDIS deployment. The publishers of official data for the electronic nautical charts are the national Hydrographic Offices (HOs) of the maritime nations, as is the case for the paper nautical charts. Non-certified data from private suppliers is not permitted for navigational purposes and is allowed only to be used as a supplement to the official nautical charts (paper or electronic). At present, data supply is still a weak point of ECDIS. The hydrographic services are public authorities that now have to switch from production of paper nautical charts to digital ECDIS data. Owing to the current paucity of public funds and the necessary restructuring programmes, only a small fraction of the earth's surface has been covered digitally with official data up to now. It is hoped that it will not be too long before an up-to-date digital global database is available for navigational purposes. . It may be mentioned that the British Admiralty, as publisher of the only set of paper nautical charts with worldwide coverage, has decided to scan all paper charts and publish them as Admiralty raster chart system (ARCS) with updates via bitmap patches.As long as there is no complete coverage with ECDIS data, ARCS data will serve as a practical alternative. Each ECDIS will also be able to read and display this raster data, although such functionality is not included in the ECDIS specification. The scanned paper charts, however, provide no real alternative to ECDIS data Standards of Equipments Several international authorities are involved in the standardization of ECDIS. The International Hydrographic Office (IHO) has the responsibility for standardizing the digital chart objects for ECDIS. The IHO has a data model and an ENC product specification (PS) as standards for ECDIS data and has published these in its Special Publication No. 57 (S57).The 'data model' is what the Chart 1 (INT 1) was for the paper nautical chart, namely, a list of all permitted hydrographic object classes.In addition, the requirement that the S57 data should be encapsulated according to the ISO 8211 standard guarantees that data from the various national HOs are compatible with one another and can be read by each ECDIS. However, the S57 data does not contain any information concerning the symbolization, the presentation of the chart on the screen. This is rectified by the second IHO standard important to ECDIS, the presentation library (PRESLIB) published in the Special Publication No. 52 (S52). The ECDIS supplier must install the presentation library in his unit with the definitions of the symbolization instructions and the colours to be used in an absolute manner irrespective of the colour monitor. This, and colour calibration instructions and techniques that the supplier of an ECDIS has to carry out, guarantees that the ECDIS charts look exactly the same on any unit from any manufacturer. In addition to the hydrographic data, there are also other chart objects that must be specified in order to make ECDIS an adequate navigational tool. A wide range of "objects" are entered into the chart by the captain and the navigators before and during the voyage of the ship. These include leg lines and waypoints, notes, observations fixed positions, commands, etc.To ensure that this is also possible with the electronic medium of ECDIS, the International Maritime Organization (IMO) has developed an ECDIS performance standard. This determines how an ECDIS has to work so that it can serve as an adequate replacement for the paper nautical chart in accordance with the International Convention for the Safety of Life at Sea, 1974 (SOLAS 74). IMO has published a list of user-defined objects under the title "Mariner's Navigational Objects" (NavObj) as an appendix to S52. The supplier of an ECDIS has to ensure that these objects can be generated, edited and deleted as required. Another specification, although not coming from IHO (but from the classification society Det Norske Veritas (DNV), is important for ECDIS functionality, in as much as it lays down the minimum requirements for bridge equipment and navigation facilities. The hardware of an ECDIS must meet the standards of the IEEE (Institute of Electrical and Electronic Engineers) for such items of equipment. To sum up the above, an ECDIS must have the following characteristics: Reading ENC data (S57) and transferring it to SENC; Presentation of objects and their characteristics according to presentation library (S52); Antgrounding function; Warning of obstructions to shippingand Updating. Various types of chart work must be possible, such as entering fixed position, route planning, entering notes and observations, and sounding, measuring of distances An ECDIS device has to meet all the standards mentioned above. These are monitored by national shipping authorities. Only an ECDIS that has been officially certified may be used in navigation as an adequate replacement for the paper nautical charts. The advantages of using ECDIS An ECDIS satisfying all the abovementioned requirements is not only an adequate replacement for the paper nautical chart but also a system containing all information important for navigation that can be called up at any time and without delay. Today, this information is still scattered about in various publications, and manual search procedures are laborious and time consuming. ECDIS also offers the possibility of automatic antigrounding alarm, which is not possible with any other navigation aid. In 1989, the "Exxon Valdez" ran aground in Prince William Sound in Alaska as a result of prematurely changing course due to false identification of an island. It leaked oil, causing a major environmental catastrophe. Had "Exxon Valdez" an ECDIS on the bridge, she could have avoided running aground. With a continually updated display of the position of the ship, the premature change of course would have probably never occurred. Moreover, the ECDIS antiground function would have produced an alarm when the vessel was approaching the shallows, warning the officer on duty of the danger. An experienced captain once remarked that with ECDIS, a navigator knows for the first time in the history of seafaring not where his ship was but where it is! A further advantage of ECDIS compared to all other navigation aids is the individual adaptation of the chart picture to the particular requirements. This is possible because the chart picture is produced only during operation. It is possible to produce the relevant shallow water contour for a super tanker with a draught of 25 m or for a ferry with a draught of only 3 m. The presentation library controls this via adjustment of the safety depth/safety contour. Automatic updating is much faster, easier and also less prone to error than chart adjustment currently laboriously carried out manually with a considerable time lag. Updating can even be called up on a digital telephone or via satellite, and incorporated instantaneously. ECDIS makes seafaring easier and thus also safer The Users of ECDIS ECDIS has a very wide range of applications and current developments in shipbuilding are making ECDIS an increasingly important and indispensable aid. The faster ships become, and the trend is clearly towards increased ship speed, the more important effective and reliable navigation aids are. In short, the faster the ship the more important ECDIS is becoming! ECDIS is used in the following areas: As an electronic nautical chart system ECDIS is used primarily by professional navigators in the shipping sector, and in particular on ferries in dangerous waters, such as on ferry lines in the Scandinavian skerries. Shipyards located on rivers deep inland which build large ocean going vessels already learned to appreciate the advantages of ECDIS when bringing their new ships safely down to the coast. Seafaring nations are setting up more Vessel Traffic Services (VTS) on their coasts and using ECDIS for their shore stations. ECDIS is also employed for national coastal and environmental protection, oil spill clearance duties, surveillance by aircraft and by the sea rescue service. Simulation systems used for the basic and advanced training of navigators, pilots, etc are equipped with ECDIS. Owners of megayachts who absolutely insist on the latest and best equipment want to sail with ECDIS. Finally, we should mention the inventor of ECDIS No single individual invented ECDIS. The currently valid standards have been developed from contributions made by companies, institutions and organizations in many countries. A pioneering role was played by Germany and Canada. Since about 1985 the development of ECDIS in Germany was promoted and significantly influenced by various projects and test beds. The prototypes of the object catalogue and presentation library were developed under auspices of the BSH by a team at the Hamburg Nautical College under Prof. Kapt. Jens Froese. This team later founded the company SevenCs (7Cs). Today, the ECDIS kernel software developed by this company is used by the leading suppliers of ECDIS and navigation equipment worldwide as its state-of-the-art technology meets all the ECDIS standards. References: Bianchetti, Fosco, "Improving the Reliability, Efficiency and Safety of ECDIS', in Onshore SENC Conversion, http://www.thsoa.org/hy99/A5.pdf/ ECDIS, Sea Information System, http://www.uk2.net/ "Electronic Charts for Maritime Safety", www.imo.org/Newsroom/contents.asp/doc Maryland Nautical Navigation Resources, at www.mdnautical.com Niles, Anthony, "ECDIS on US Inland Waterways at http://www.thsoa.org/hy03/9h_2/ Univ. of S. Mississippi, Dept. of Marine Science, "ECDIS Lab Helps Chart Future of US Marine Science" at http://www.usm.edu/marine/news/release/ecdis_future.htm SEVENCS-(W), "ECDIS and Marine Geographical Information Systems" at www.sevencs.com Read More