IMSML Website Article 30/2023: Resolution MSC.530(106) – Performance Standards for Electronic Chart Display and Information Systems (ECDIS), Part 2 of 3, MODULE B - Operational and Functional Requirements
This is Part 2 of a 3 Part Article Series on ECDIS. The focus of today’s IMSML Website Article 20/2023 is on Module B, Operational and Functional Requirements. The following are the contents of today’s article:
[1] Display of System Database Information;
[2] Scale;
[3] Display of Other Navigational Information;
[4] Display Mode and Generation of the Neighbouring Area;
[5] Colours and Symbols;
[6] Display Requirements;
[7] Route Planning, Monitoring and Voyage Recording;
[8] Calculations and Accuracy;
[9] Performance Tests, Malfunctions Alerts and Indications;
[10] Back-up Arrangements.
Now on to the article … … …
[1] Display of System Database Information
ECDIS should be capable of accepting and converting an ENDS and its updates into a system database. It should be capable of displaying and processing all such database information as specific by the IHO. In addition, it should also be capable of accepting conversion from ashore in accordance with IHO Resolutions, see Section 5.1.
The database information should be available for display during route planning. Route planning monitoring should be sub-divided into: Display Base, Standard Display and All other Information (please reference to Appendix 2 in IMSML Website Article 31/2023), see Section 5.2.
ECDIS should present the standard display at any time by a single operator action, see Section 5.3. A return to the most recent manually selected setting for the display when ECDIS is switched on following a power failure, see Section 5.4. Although it should be easy to add or remove information from the ECDIS display, it should not be possible to remove information contained in the display base, see Section 5.5.
ECDIS should display on demand the information about chart objects associated with an operator-identified geographical position (eg by cursor picking), see Section 5.6. Usage of chart scale values or ranges in nautical miles should be possible when the appropriate step are taken to change the display scale, see Section 5.7.
Selection of a safety contour by a mariner from the information provided by the system database should be possible. As a general rule, emphasis of the safety contour over other contours on display should be made by ECDIS, see Section 5.8. However, there are four exceptions to this general rule:
[a] A safety contour is not specified by the Mariner. The default setting in this case is 30m. Note that if the safety contour is specific by the Mariner, or the default 30m contour is not displayed in the system database, the system should default to the next deeper contour, see Section 5.8.1;
[b] Where there is a change in the source data, and the safety contour in use becomes unavailable, the safety contour will default to the next deeper contour, see Section 5.8.2;
[c] For cases [a] and [b] above, an ‘indication’ should be provided, see Section 5.8.3;
[d] A permanent display of safety contour and safety depth setting should be able to be selected by a mariner, see Section 5.8.4.
Whenever spot sounding are selected for display, ECDIS should emphasise soundings equal to or less than the safety depth, ie it should be possible for the mariner to select a safety depth, see Section 5.9. It should be possible to use dynamic water level adjustment and an indication should be provided, see Section 5.10.
ENDS and all its updates should be displayed. This must be done without any degradation of their information content, see Section 5.11. Monitoring of ENDS and all its updates by ECDIS are to ensure that it has been correctly loaded into the system database, see Section 5.12. Ends data and its updates should be clearly distinguishable from other displayed information (including those listed in Appendix 3, note: See IMSML Website Article 31/2023 for this), see Section 5.13.
[2] Scale
The following are circumstances under Section 6.1 where ECDIS are to provide an ‘indication’ (ie produced here in verbatim):
[a] the information is displayed at a larger scale than that contained in the ENC, see Section 6.1.1;
[b] own ship's position is covered by an ENC at a larger scale than that provided by the display, see Section 6.1.2; or
[c] information at own ship's position is not displayed because of applying scale minimum for display, see Section 6.1.3.
[3] Display of Other Navigational Information
General
Other navigational information may be added to the ECDIS display. For example, radar and AIS information. However, this additional information should not degrade the existing system database information. The additional information should also be clearly distinguishable from the system database information, see Section 7.1.
For ease of use, a single operator action should be possible to remove radar, AIS and other navigational information, see Section 7.2. Also for the sake of simplicity, there should be a common reference system for ECDIS and added navigational information, see Section 7.3.
Radar
A radar image and/or tracked target information, may be found in transferred radar information, see Section 7.4.1. The chart and AIADR image should match in scale, projection and orientation, when a radar image is added to the ECDIS display, see Section 7.4.2. Automatic adjustment for antenna offset and the conning position should be made automatically from the radar image and the position sensor, see Section 7.4.3.
[4] Display Mode and Generation of the Neighbouring Area
Generally, the default ‘north-up’ orientation should always be possible for display of the system database information. However, other orientations are permitted, although these should be altered in steps large enough to avoid unstable display of the chart information, see Section 8.1. True motion mode should be provided by ECDIS, although other modes are also permitted, see Section 8.2. When true motion is in use, reset and generation of the chart display of the neighbouring area should take place automatically at the own ship’s distance from the edge of the display (as determined by the mariner), see Section 8.3.
The displayed chart area and the position of own ship relative to the edge of the display can be manually changed, see Section 8.4. If the area covered by the ECDIS display includes waters for which no ENC at a scale appropriate for navigation is available, the areas representing those waters should carry an indication (see appendix 5) to the mariner to refer to the paper chart or to the RCDS mode of operation (see appendix 7), see Section 8.5.
Note: For Appendix 5 and Appendix 7, see IMSML Website Article 31/2023.
[5] Colours and Symbols
System database information should be represented using IHO-recommended colours and symbols, see Section 9.1. In addition there should also be compliance the requirements contained in the IMO Standards for Navigational Symbols, see Section 9.2. Choice is important, and a mariner should be permitted by ECDIS to select whether own ship is displayed in true scale or as a symbol, see Section 9.3.
[6] Display Requirements
There are two display requirements for information by ECDIS:
[1] Route planning and supplementary navigation tasks, see Section 10.1.1;
[2] Route monitoring, see Section 10.1.2.
The minimum size of 270mm v 270mm is the effective size of the chart presentation, see Section 10.2. The colour and resolution recommendation of IHO as referenced in IHO Publication S-52 - Specifications for Chart Content and Display Aspects of ECDIS and S-101 Portrayal Catalogue (see Appendix 1) and S-98, should be met, see Section 10.3 (Note that Appendix 1 is featured in IMSML Website Article 31/2023). The displayed information should be clearly visible to more than one observer in the conditions of light normally experienced on the bridge of the ship, either day or night, see Section 10.4. If a display is customised, this should be permanently indicated. Information categories which have been removed from the display should be shown on demand, see Section 10.5
[7] Route Planning, Monitoring and Voyage Recording
Simplicity and reliability are the core principles in this category, see Section 11.1. The largest scale data available in the system database for a given area, is required by Section 11.2 for all alerts or indication of crossing the ship’s safety contour and of entering a prohibited area indicated in Appendix 5 (Note: For Appendix 5, see IMSML Website Article 31/2023).
Route Planning
Route planning includes both straight and curved segments, see Section 11.3.1. Adjusting a planned route alphanumerically and graphically includes the following:
[1] Adding waypoints to a route, see Section 11.3.1;
[2] Deleting waypoints from a route, see Section 11.3.2;
[3] Changing the position of a waypoint, see Section 11.3.3.
Planning one or more routes, as well as alternative routes should be possible. Distinguishing the selected route from other routes is crucial, see Section 11.3.3. If a mariner plans a route closer than a user-specified distance from own ship’s safety contour, a graphical indication is required, see Section 11.3.4.
This is also required if there is a user-selectable category of a prohibited area, or a geographic area where special conditions exist (see for example Appendix 4. Note, for the Appendices, see IMSML Website Article 31/2023). A graphical indication is also required where where there is a fixed or floating aid to navigation or isolated danger, see Section 11.3.5. These indications should be based on IHO standard.
As for de-selection, there should be a permanent indication when any user-selectable categories are deselected. Details of the de-selection should be available on demand, see Section 11.3.5.
As defined by IHO standards, it should be possible for a mariner to make selections, by taking into account accuracy of information of relevant hydrographic information, see Section 11.3.6. It should also be possible to perform a complete route check to support the appraisal and planning process, see Section 11.3.7. A cross track limit of deviation from the planned route, at which an automatic off-track alarm should be activated, should be possible for a mariner to specify, see Section 11.3.8.
Route Monitoring
The selected route and own ship’s position should appear whenever the display covers the area, see Section 11.4.1. Automatic functions such as updating the ship’s position and providing alerts and indications should be continuous, see Section 11.4.2. It should be possible to select ECDIS to give an alarm and related graphical indication if own ship will pass closer than a user-selected distance from the safety contour (if within a specified distance set from the safety contour), see Section 11.4.3. An alarm should be given when the specified cross track limit for deviation from the selected route is exceed (if defined by the mariner when route planning), see Section 11.4.5. Similarly, a warning or caution should be given from a user-selectable category of danger (eg obstruction, rocks etc) that is shallower than the mariner’s safety contour, see Section 11.4.6. A graphical indication should also be given if the selected route passes closer than a user-specified distance from the safety contour, see Section 11.4.7, and also for a user-selectable category of a prohibited area or a geographic area where special conditions exist, see Section 11.4.8.
The ship’s position is derived from a continuous positioning system of an accuracy consistent with the requirements of safe navigation. A second independent positioning source should be provided (preferably a different type), see Section 11.4.10. When the input from the position, heading or speed sources are lost, ECDIS should provide a warning, see Section 11.4.11. When the ship reaches a specified time or distance set by the mariner, in advance of a critical point on the planned route, a warning should be given by ECDIS, see Section 11.4.12. ECDIS should give a warning when the positioning system and the system database are not on the same geodetic datum, see Section 11.4.13.
It should be possible to display alternative routes in addition to the selected route. The selected route should be clearly distinguishable from the other routes. During the voyage, it should be possible for the mariner to modify the selected route or change to an alternative route, see Section 11.4.14. Section 11.4.15 stipulates that it should be possible to display the following:
[1] time labels along a ship's track manually on demand and automatically at intervals selected between 1 and 120 minutes, see Section 11.4.15.1; and
[2] an adequate number of points, free movable electronic bearing lines, variable and fixed range markers and other symbols required for navigation purposes and specified in Appendix 3, see Section 11.4.15.2. (Note: For Appendix 3, see IMSML Website Article 31/2023)
Selection and display of geographical coordinates of any position should be able to be made on demand, see Section 11.4.16. This could also be done manually and adjusted an indicated alphanumerically, and maintained until altered by the mariner and recorded automatically, see Section 11.4.17. Manual entry and plotting via obtained bearing and distance lines of position, and calculating the resulting position of own ship should be a provided ECDIS capability. It should therefore be possible to use the resulting position as an origin for dead reckoning, see Section 11.4.18. Discrepancies between the positions obtained by continuous positioning systems and positions obtained by manual observations, should be indicated by ECDIS, see Section 11.4.19.
Voyage Recording
Reproduction of certain minimum elements required to reconstruct the navigation should be stored by ECIDS. This will be followed by verification of the official database used during the previous 12 hours, see Section 11.5.1. The following data should be recorded at one minute intervals (ie produced here in verbatim):
[1] to ensure a record of own ship's past track: time, position, heading, and speed, see Section 11.5.1.1;
[2] to ensure a record of official data used: ENC source, edition, date, cell and update history, see Section 11.5.1.2; and
[3] any changes in safety contour, look ahead and route monitoring alert settings, see Section 11.5.1.3.
Note that for the information listed in Section 11.5.1.2 to 11.5.1.3, ECDIS should output the information to a voyage data recorder.
At time mark intervals not exceeding 4 hours, ECDIS should record the complete track for the entire voyage, see Section 11.5.3. It should not be possible to manipulate or change the recorded information, see Section 11.5.4. ECDIS should have a capability to preserve the record of the previous 12 hours and the voyage track, see Section 11.5.5.
[8] Calculations and Accuracy
The accuracy of all calculations performed by ECDIS should be independent of the characteristics of the output device and should be consistent with the system database accuracy, see Section 12.1 Bearings and distances drawn on the display or those measured between features already drawn on the display should have accuracy no less than that afforded by the resolution of the display, see Section 12.2. Pursuant to Section 12.3 , the system should be capable of performing and presenting the results of at leats the following calculations (ie reproduced here in verbatim):
[1] true distance and azimuth between two geographical positions, see Section 12.3.1;
[2] geographic position from known position and distance/azimuth, see Section 12.3.2; and
[3] geodetic calculations such as spheroidal distance, rhumb line and great circle, see Section 12.3.3.
[9] Performance Tests, Malfunctions Alerts and Indications
ECDIS should be provided with means for either automatically or manually carrying out onboard tests of major functions. In case of a failure, the test should display information to indicate which module is at fault, see Section 13.1. ECDIS should provide a suitable warning or indication of system malfunction, see Section 13.2.
[10] Back-up Arrangements
Pursuant to Section 14, adequate back-up arrangement should be provided to ensure safe navigation in the case of a ECDIS failure, see Appendix 6. Note that for Appendix 6, see IMSML Website Article 31/2023. The required back-up arrangements are as follows:
[1] Facilities enabling a safe takeover of the ECDIS functions should be provided in order to ensure that an ECDIS failure does not develop into a critical situation, see Section 14.1;
[2] A backup arrangement should provide means of safe navigation for the remaining part of a voyage in the case of an ECDIS failure, see Section 14.2.
Thank you for reading IMSML Website Article 30/2023
Stay tuned for the next IMSML Website Article 31/2023: Resolution MSC.530(106) – Performance Standards for Electronic Chart Display and Information Systems (ECDIS), Part 3 of 3, MODULE C - Interfacing and Integration and Content of the Appendices
Signing-off for today,
Dr Irwin Ooi Ui Joo, LL.B(Hons.)(Glamorgan); LL.M (Cardiff); Ph.D (Cardiff); CMILT
Professor of Maritime and Transport Law
Head of the Centre for Advocacy and Dispute Resolution
Faculty of Law
Universiti Teknologi MARA Shah Alam
Selangor, Malaysia
Wednesday, 11 October 2023
Note that I am the corresponding author for the IMSML Website Articles. My official email address is: uijoo310@uitm.edu.my