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1、Electronic Chart Display and Information Systems (ECDIS) Lesson 14,Learning Objectives:,Be familiar with types of electronic charts Know Advantages and Disadvantages of different Electronic Chart formats Understand difference between ECDIS and ECS Be familiar with display characteristics of ECDIS Un
2、derstand the limitations of ECDIS Understand Navys policy and plan on ECDIS Understand the risk of over-reliance on ECDIS,Background,Electronic databases, operating systems, computer technology and the widespread deployment of Digital technology has made it possible to employ electronic charts at se
3、a. In addition, the advent of continuous and automated positioning systems (such as GPS), have made it possible to take maximum advantage of electronic charting.,The benefits of the integrated system GPS and chart data in digital format include:,- Real time position . - Automated navigation plotting
4、. - Reduce manning - Minimizing human error . - Alert to navigation dangers. - Dramatically increase awareness in low visibility.,Electronic Charting Systems,Advances in technology have made it possible to replace the traditional paper charts with Electronic Charting Systems. All electronic charting
5、 systems fall into two categories. The two categories are: ECDIS (Electronic Charting and Display System) ECS (Electronic Charting System).,Electronic Chart System (ECS),A commercial electronic chart system not designed to satisfy the IMOs requirements To be used as an aid to navigation, in conjunct
6、ion with paper charts,Electronic Chart Display & Information System (ECDIS),An electronic chart system which does satisfy IMO requirements, when used with an ENC (electronic navigation chart). positional information from navigation sensors to assist the mariner in route planning and route monitoring
7、, and by displaying additional navigation-related information if required,In other words,ECDIS is a system that is able to display electronic chart information with: - automatic position updates - built in redundancy - that will assist the mariner in all aspects of Navigation. It is the legal equiva
8、lent of a paper chart.,It is Not an ECDIS if,Equipment is not legally approved. Does not have adequate electronic chart coverage. Does not have chart updating capability. Even though an ECS may perform many of the same functions as an ECDIS, it is not the legal equivalent of an ECDIS. It may only be
9、 used for “situational awareness”.,What makes up an ECDIS or ECS?,Position inputs (GPS, DGPS, LORAN, Radar, gyro, fathometer, etc.) Electronic Navigation Charts (ENC) System Electronic Navigation Charts (SENC),Electronic Navigational Chart (ENC),An electronic chart issued by a national hydrographic
10、authority. The ENC contains all the chart information necessary for safe navigation, and may contain supplementary information in addition to that contained in the paper chart (e.g., sailing directions) which may be considered necessary for safe navigation,System ENC (SENC),The database created by a
11、n ECDIS from the ENC data There are: different types of ENC data various formats differences in the level of content,System Electronic Navigational Chart (SENC),Not all charts are equal.,Many different formats exist for electronic charts. The two major types are vector based and raster charts. Raste
12、r charts are scanned paper charts. Most vector charts are digitized paper charts, thereby inheriting any errors (and possibly introducing some!) Countries are producing unique digital charts based on their interpretation of IHO standards.,ENC,DNC,BSB,ARCS,C-MAP,Navionics,Transas,The Types of EC Form
13、ats are: Raster and Vector,NIMA Digital Nautical Chart (DNC),IHO S-57 Electronic Navigational Chart (ENC),NOAA Raster Nautical Chart (RNC),Digital Chart Formats,The Basic Difference,Raster charts are simply bitmap images created by scanning a paper chart Vector charts portray charted features as poi
14、nts, lines, or areas with amplifying information (attributes) found in an associated database,Raster Charts,A set of colored pixels representing chart information as a picture on computer screen Pixels are color coded, but do not represent features explicitly,Advantages of Raster,Looks like a paper
15、chart (appeals to traditionalists) Cheap and easy to produce (scan existing paper chart) World-wide availability,Disadvantages of Raster,High scan resolution required for detailed chart.lots of CPU memory required and slower refresh rates Zooming degrades quality Difficult to changes elements of the
16、 chart, since its all one file Mixed pixelsis it water or land?,Vector Charts: More detail,A set of accurately positioned lines (vectors), points and areas, with associated attributes (e.g. “shoreline”, “buoy - red”) organized in a database accessed by clicking on displayed symbol Vector data is org
17、anized into many separate files, or “layers”,The Advantages of Vector Charts,Information on Chart can be linked to specific points. (Click on light and you can retrieve more info, like a picture of the light) Underlying database allows queries and layer selection Zooming reveals detail File size is
18、a fraction of the size of raster Allows the user to display the information that is necessary for the ships current mission.,Disadvantages of Vector,Looks “different” from a paper chart Needs more powerful computer and expensive display to meet IHO/DoD requirements Complex, expensive, and time-consu
19、ming to produce,USN Approach is to use NIMAs Digital Nautical Chart (DNC), a vector based format.,DNC with Base data only showing (Less clutter),Standard Display with Depth Contours,The user defines what features are necessary!,Standard Display with Spot Soundings,DNC with user-defined Color,All Fea
20、tures,Which is better?,Depends on your point of view. Raster is easier and cheaper to produce, but vector provides much more information to the navigator DoD standard is Vector Product Format -DNC Digital Nautical Chart, produced by NIMA,US Navy Policy,The Chief of naval Operation ( CNO) issued a di
21、rective in march 1998 establishing minimum ECDIS standards (ECDIS-N) and calling for a transition of the entire Navy fleet from paper based charts to electronic digital Chart by FY 2007. This has recently changed to 2004, with the first ECDIS-N certified battlegroup deploying in FY01. Until then, sh
22、ips may use an ECS for enhanced situational awareness, but the paper chart must be maintained as well.,USN ECDIS-N Requirements,Navy standard, automated and continuous positioning systems Display of radar, visual and celestial navigation fix information Ability to read and display National Imagery a
23、nd Mapping Agency (NIMA) Digital Nautical Charts (DNCs) System-to-system interoperability,The US Navy Approach,Several Different Programs including NAVSSI (USN), NAVSSI-Lite, and VMS/IBS. All programs will use NIMAs Digital Nautical Charts. Most systems will also be able to read raster charts.,ECDIS
24、-N Platforms,169 combatants scheduled for NAVSSI/NAVSSI Lite, including NIMITZ class aircraft carriers, ARLEIGH BURKE class destroyers, TICONDEROGA class cruisers, WASP class amphibious assault ships and Perry class frigates.,Virginia class SSN will employ ECDIS-N software for its Navigation Data Di
25、stribution and Display (ND3) system.,13 FAMOUS class cutters. There is potential for installation on other cutters.,Piloting Guidance,Automatically calculates: cross-track error recommended course to steer accounting for set/drift nearest hazard next navigation aid depth distance and time to turn,Mi
26、litary standard navigation report,Tabular turnpoint solution data,Tide and Current Information,Displayed on the chart,and graphically in pop-up windows.,The Risks of ECDIS,ECDIS is only a tool that helps a mariner safely and effectively navigate a ship. It is not the end-all be-all to ship navigatio
27、n. One of the biggest risks with the transition to ECDIS is an over reliance in the information provided,Some things to consider,Poor GPS performance DGPS used/not used ECDIS malfunction installation setup ENC compilation errors (e.g., datums) chart (errors, omissions, out-dated) survey errors human error,Questions?,Homework,Read Hobbs: pg 166-176 Surface Ship Operations Chapter 4 Syllabus Update 21 March: Weather and Radar Navigation Everything else is as scheduled,