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UKHO launches three new Port Approach Guides for Singapore launches three new Port Approach Guides for Singapore.pdfUKHO launches three new Port Approach Guides for Singapore2016-10-27T23:00:00Z
Get compliant passage plans faster with ADMIRALTY Passage Planner - UKHO Press Release - ADMIRALTY Passage Planner.pdfGet compliant passage plans faster with ADMIRALTY Passage Planner2016-10-03T23:00:00Z
UKHO to release new digital charts for expanded Panama Canal Press Release - UKHO to release new digital charts for expanded Panama Canal.pdfUKHO to release new digital charts for expanded Panama Canal2016-06-14T23:00:00Z



Category Zones of Confidence (CATZOC) -dispelling the myths Zone of Confidence (CATZOC) values are used to indicate the accuracy of data presented on charts to assist mariners with determining a safe Under Keel Clearance (UKC). This blog aims to answer questions on CATZOC values and the introduction of CATZOC to paper charts.Category Zones of Confidence (CATZOC) -dispelling the myths2017-03-16T00:00:00ZCategory Zones of Confidence (CATZOC) –dispelling the myths<p class="admiraltyElement-P">​​​​​​​​​​​​​​​​​​​​​​​​​Category Zone of Confidence (CATZOC) values are used to indicate the accuracy of data presented on charts to assist mariners with determining a safe Under Keel Clearance (UKC). This blog aims to answer 2 key questions that we regularly receive at our <a href="/_layouts/15/FIXUPREDIRECT.ASPX?WebId=6828029c-41f1-4124-bef3-6404266560b7&TermSetId=41e4d507-3ce2-45c5-9546-770d62bf0bc6&TermId=815e7e6b-02e9-4b14-9d4c-e37150da40fb">Living with ECDIS Seminars​</a> on this important feature: </p><div><ul class="admiraltyElement-P"><li><p class="admiraltyElement-P">“Do I need to revert to paper charts in areas where the ENC Category Zone of Confidence is set to C or less?” ​<br></p></li><li><p class="admiraltyElement-P">“Why do some paper charts have Source Diagrams and others have CATZOC Diagrams?” <br></p></li></ul><p class="admiraltyElement-P">​</p><h3 class="admiraltyElement-H3"> What is CATZOC?​</h3> <br> <p class="admiraltyElement-P">Category Zone of Confidence (CATZOC) values are assigned to geographical areas to indicate whether data meets a minimum set of criteria for position, depth accuracy and seafloor coverage. The Zone of Confidence (ZOC) value is dependent on the positional and depth accuracy of the survey.</p><p class="admiraltyElement-P">By understanding the accuracy limitations of the underlying data in greater detail, the mariner can manage the level of risk when navigating in a particular area.​</p><p class="admiraltyElement-P">ECDIS display these CATZOC values  in ENCs using a triangular or lozenge shaped symbol pattern. The number of stars contained within these symbols denotes the CATZOC value. For example six stars are given to the highest level of data quality (A1) and two stars to the lowest (D). A single star is not used to avoid possible confusion with a rock symbol. Areas that have not been assessed for CATZOC are shown as the symbol (U) for unassessed.</p><p class="admiraltyElement-P">Our Zones of Confidence (ZOC) table outlines the position accuracy, depth accuracy and seafloor coverage for each of these values to help you manage the levels of risk during navigation.</p><br>​​ <p class="admiraltyElement-P"> <a href="/AdmiraltyDownloadMedia/Blog/CATZOC%20Table.pdf">Download the Zones of Confidence (ZOC) table​</a> <span class="admiraltyStyle-pdf"></span></p><p class="admiraltyElement-P">​</p><h3 class="admiraltyElement-H3">Do I need to revert to paper charts in areas where the ENC Category Zone of Confidence is set to C or less?</h3> <br> <p class="admiraltyElement-P">No, you don’t. The same data is used for a paper chart and an ENC, therefore neither is more accurate than the other. In fact, an ENC can give you a greater insight into the data via the ’Quality of Data’ and survey reliability features.</p><p class="admiraltyElement-P">The example below clearly highlights that there is no additional information on the paper chart that would aid the mariner in calculating an under keel clearance, and therefore there is no requirement to switch from navigating with ENCs and ECDIS when the CATZOC value is C or less.​</p><p class="admiraltyElement-P"> ​<img class="admiraltyImage-contentImages admiraltyStyle-lightbox" src="/SiteCollectionImages/Blog%20Images/ENCvsPaperChart3.jpg" alt="" style="margin:5px;" /> </p><p> </p><h4 class="admiraltyElement-H4" style="text-align:center;"> GB ENC showing M_QUAL area with CATZOG value of C and source data diagram for paper chart BA1977</h4><p class="admiraltyElement-P" style="text-align:center;"> <br>  </p><h3 class="admiraltyElement-H3">Why do some charts have Source Diagrams and others have CATZOC Diagrams?</h3> <br> <p class="admiraltyElement-P">The Source Diagram on a paper chart is the traditional method of indicating when and how the survey was conducted to collect the hydrographic data. From this information, the mariner must deduce the degree of confidence to place in charted data. </p><p class="admiraltyElement-P">By including CATZOC Diagrams on paper charts, more detail is provided on the accuracy of the underlying hydrographic information than was previously available in the Source Diagram. Providing this additional detail means that the mariner can make more informed decisions when passage planning and calculating under keel clearances. </p><p class="admiraltyElement-P">As you can see from the examples below, the UKHO are gradually moving to a new style of Source Diagrams including ZOCs.​</p><p class="admiraltyElement-P"> ​ <img class="admiraltyStyle-lightbox admiraltyImage-contentImages" src="/SiteCollectionImages/Blog%20Images/SourceDiagramandCATZOG3.jpg" alt="" style="margin:5px;" /> <br></p><h4 class="admiraltyElement-H4" style="text-align:center;">New CATZOC diagram (top) and traditional source diagram (bottom)</h4></div><div><br> </div><h4 class="admiraltyElement-H4">This blog was written by Thomas Mellor, the Head of OEM Technical Support and Digital Standards at the UKHO​. He's also speaker at the UKHO's 'Living with ECDIS' Seminars which are designed to help ship managers and officers to understand the latest legal and maintenance issues in relation to ECDIS. <a href="/_layouts/15/FIXUPREDIRECT.ASPX?WebId=6828029c-41f1-4124-bef3-6404266560b7&TermSetId=41e4d507-3ce2-45c5-9546-770d62bf0bc6&TermId=815e7e6b-02e9-4b14-9d4c-e37150da40fb">You can find out more about these seminars here</a>.</h4><div>​​<br>​</div>
The new S-52 ECDIS Standards: What do they mean for you? new S-52 ECDIS Standards: What do they mean for you?2017-02-21T00:00:00ZThe new S-52 ECDIS Standards: What do they mean for you?<p class="admiraltyElement-P">​​​​On an ADMIRALTY paper chart our highly skilled cartographers have presented accurate and reliable information to the mariner for over two hundred years.  However, the responsibility for the portrayal of an ENC on an ECDIS screen is controlled by the ECDIS standard ‘S-52’. This is authored by the <a href="">International Hydrographic Organization</a> (IHO).<br></p> <br> <p class="admiraltyElement-P">ECDIS manufacturers refer to these IHO ECDIS Standards when developing their software, specifically the latest Presentation Library (4.0) within S-52.  This contains instructions for the ‘drawing engine’ within the ECDIS on how to display symbols, colours and line styles on the screen. ​</p><p> </p><h3 class="admiraltyElement-H3">What are the changes within Presentation Library 4.0?</h3> <br> <p class="admiraltyElement-P">​As well as ensuring greater consistency in the display of ENC data across all ECDIS, the new standards deliver other benefits for the mariner. </p><p class="admiraltyElement-P">Firstly, the latest Presentation Library addresses the number one complaint levelled​ at ECDIS; constant audible alarms.  By providing clear guidance to ECDIS manufacturers on ENC objects that will raise an alarm, the IHO has tackled the issue of alarm fatigue on the bridge. </p> <br> <p class="admiraltyElement-P">Also, information such as fairway and anchorage area names now appear on screen, with landmarks, lights and buoys viewable via a ‘hover-over’ function.  Both initiatives reduce the time-consuming need to find information buried in a pick report.​</p><p class="admiraltyElement-P" style="text-align:center;">​<img class="admiraltyImage-contentImages admiraltyStyle-lightbox" src="/SiteCollectionImages/Blog%20Images/FairwayNameExample.jpg" alt="" style="margin:5px;" /></p><p class="admiraltyElement-P"> </p><p class="admiraltyElement-P" style="text-align:center;">This before and after photo demonstrates the inclusion of fairway and anchorage names within in the latest presentation library. This change reduces the need to find important information in a pick report ​​</p><p> </p><h3 class="admiraltyElement-H3" style="font-family:"johnston itc w01 medium", arial;font-style:normal;">When are the new standards due to enter into force​?​<br><br></h3><p><span style="font-family:"johnston itc w01 light", arial;font-size:20.8px;font-style:normal;font-weight:normal;">Owners are expected to switch to the new Presentation Library</span>​ by the 31 August 2017. <span style="font-family:"johnston itc w01 light", arial;font-size:20.8px;font-style:normal;font-weight:normal;">However, the upgrade requirements will vary from ship to ship, so we continue to encourage every owner to speak to their ECDIS manufacturer now in order to ensure a smooth switchover and to take advantage of the new ECDIS Standards at the earliest opportunity, rather than waiting until the new deadline of 31 August 2017.</span>​</p><h3 class="admiraltyElement-H3"><br></h3><h3 class="admiraltyElement-H3">How can I find out more?​</h3><br> <p class="admiraltyElement-P">Our range of​ ECDIS and ENC reference publications have been updated to reflect the latest changes to the presentation library and are available as part of the <a href="/_layouts/15/FIXUPREDIRECT.ASPX?WebId=6828029c-41f1-4124-bef3-6404266560b7&TermSetId=41e4d507-3ce2-45c5-9546-770d62bf0bc6&TermId=addb145d-1d93-42cb-ab41-59e37d3fbcb6">ADMIRALTY e-Nautical Publications range​</a>. </p> ​​ <p class="admiraltyElement-P">Our free seminars on ‘Implementing ECDIS’ and ‘Living with ECDIS’, are also designed to ensure the navigational benefits of ECDIS are achieved in an efficient and compliant manner. Both will give you an opportunity to ask UKHO and independent experts, questions about ECDIS implementation and management, including the latest changes brought through by the IHO. They are all free to attend and places can be booked online. ​<br></p> <br> <font size="1"></font> <p class="admiraltyElement-P">› <a href="/_layouts/15/FIXUPREDIRECT.ASPX?WebId=6828029c-41f1-4124-bef3-6404266560b7&TermSetId=41e4d507-3ce2-45c5-9546-770d62bf0bc6&TermId=815e7e6b-02e9-4b14-9d4c-e37150da40fb">Find out more about the UKHO's 'Living with ECDIS Seminars'</a></p> <p class="admiraltyElement-P"><a href="/_layouts/15/FIXUPREDIRECT.ASPX?WebId=6828029c-41f1-4124-bef3-6404266560b7&TermSetId=41e4d507-3ce2-45c5-9546-770d62bf0bc6&TermId=6fbbc1c7-2348-4a03-9975-f98b93078634">› Find out more about our ECDIS and ENC reference publications</a></p><p> </p><p class="admiraltyElement-P">​​​</p>


  • Our revised ADP user guide covers key functions, helping bridge crews to install, activate and update ADP on board:

    About 7 days ago

  • ADMIRALTY Digital Publications give bridge crews faster updates and easier access to the information they need:

    About 14 days ago

  • ADMIRALTY Digital Publications are computer-based versions of the UKHO's paper-based nautical reference guides:

    About 16 days ago

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