Updating and Correcting Nautical Charts.

Correcting and Updating Nautical Charts

1. Updating and Correcting Nautical Charts Group 6: Jorge, John Lawrenze Macamay , Prince Justin Lendio, Rolando DALAG, KEN JONAS

2. Updating and Correcting Nautical Charts

3. Updating and Correcting Nautical Charts One of the most crucial items on the ship is the chart. Nowadays modern ships have come in electronic chart systems and it is very easy to correct them, but there are still many companies that are using traditional paper charts on their vessels primary sources for navigation. Updating a paper chart is a bit of hard work. Updating and correcting it should be very careful to do it because the navigation of the vessel depends on the correction made by us, navigators. The chart correction needs to be done with all sincerity because one of our mistakes could endanger the crew and the ship as a whole.

4. CHART CORRECTIONS Features shown on charts change, either because they are man made, or due to natural changes. Therefore, it is essential that our charts are corrected, or updated regularly. The Hydrographic Office issue Notices to Mariners (NTMs) each week which cover all the changes, in all their publications world-wide. As there are thousands of charts and books on this list, it can be a bit cumbersome for a small boat skipper. In addition, they publish Notices to Mariners weekly on their website www.ukho.gov.uk Obviously the latter are easier for most yachtsmen to use.

5. CHART UPDATES Critical Corrections Critical data includes any changes that may pose a danger to navigation and that mariners should be informed of as soon as possible. This may include newly discovered rocks, wrecks, shoals, or other dangers to navigation, as well as changes in the positions or characteristics of aids to navigation (buoys, beacons, and lights). Routine Corrections All non-critical data is categorized as "routine." This includes the results of ordinary hydrographic and shoreline surveys, which can be extensive.

6. What are notices to mariners ( nTN )? The situation at sea changes continuously. The Hydrographic Service monitors changes and publishes the necessary corrections to its publications in order to give mariners information about the current situation. Notices to Mariners ( NtM ) are  corrections to nautical charts and publications . NtM only contain information which is vitally important to safety at sea. Mariners are obliged to keep their products up-to-date with NtM until a new edition is issued.

7. notices to mariners ( nTM )

8. WGS84 datum WGS84, or the World Geodetic System 1984, is a comprehensive geodetic datum used extensively for navigation, mapping, and geospatial analysis. It serves as the foundational reference for the Global Positioning System (GPS) and is crucial for accurately determining geographic locations on Earth.

9. WGS84 comprises four key components: Ellipsoid : WGS84 uses a specific mathematical model of the Earth's shape, known as an ellipsoid. This model approximates the Earth's dimensions and curvature, allowing for accurate calculations of geographic coordinates. Horizontal Datum : This aspect defines how the ellipsoid is positioned relative to the Earth's surface. The WGS84 horizontal datum includes the ellipsoid and an anchor point, which is known with high precision (approximately 2 cm) to establish a consistent framework for latitude and longitude measurements.

10. WGS84 comprises four key components: 3. Vertical Datum : This component allows for the measurement of elevation relative to the WGS84 ellipsoid. It provides a reference for determining heights above or below the ellipsoid, which is essential for various applications, including drone imagery and topographic mapping. 4. Coordinate System : WGS84 includes a geographic coordinate system that uses degrees for latitude and longitude, with Greenwich as the prime meridian. The EPSG code for WGS84 is 4326, which is widely recognized in geospatial data applications

11. Applications and Importance of WGS84

12. Types of Chart Correction The following corrections are listed in Weekly Notices to Mariners (ANM): 1. Permanent corrections are listed in the serial number, from the beginning of the year. A minor correction can be corrected by pen and areas of chart known as “blocks” are issued for major corrections.

13. Types of Chart Correction 2. Temporary and Preliminary (T & P) corrections are carried out in pencil and are erased after they are canceled or superseded by permanent correction. 3. Navigational warnings are listed under NAVAREAs/Navigational areas. 4 . A New edition of a chart is issued when the major portion of a chart is revised.

14. Things Required for Chart Correction: Admiralty Notices to Mariners C hart correction pens H ighlighter P aper cutter C utting board Hacksaw blade P arallel ruler T racing paper Pencil Ruler

15. Before Starting Chart Correction: Highlight the charts which you have on board with a highlighter pen in the correction log (NP 133A). Note down in the correction log correction numbers from all ANM’s, that are to be corrected, in an ascending order. Voyage charts must be corrected first, followed by all charts on board. Pull out the affected chart and confirm from the notice number, whether the last correction affecting the chart is entered at the bottom left-hand corner of the chart.

16. After Completing Each Correction: Note down the correction number at the bottom left-hand corner of the chart. Note down the correction number and week in which that correction received in correction log (NP 133A). Strike out the correction number written in Chart Correction Log by pencil. Strike out the chart number at the correction in ANM or the tracing. Before moving to the next chart, correct all corrections (as noted from all ANM’s) affecting the chart.

17. Correction for a New Chart: When a new chart or new edition of a chart is received on board this procedure must be followed: Highlight the chart number in the correction log. Erase all the old corrections (in case of the new edition and write the edition date in the pen). Enter the Chart Folio and sequence number, from the index. In case of a new edition, this information is already present.

18. Correction for a New Chart: 3. Correct the chart for any pending corrections. Record these corrections in Chart correction log in pencil. 4. Correct the Admiralty Chart Catalogue (NP 131) if affected. 5. Cancel the old edition of the chart by writing boldly on top “CANCELLED” and remove it from the bridge.

19. Correction to old Charts: If a chart has not been kept up-to-date and the last correction effected on the chart is very old, use the following procedure to correct it: Check that the edition is currently in the Cumulative Notice to Mariners. Check in the latest Cumulative Notice to Mariners against the chart number, the number of uncorrected notices. Note them down in the correction log. Start by correcting the latest correction first and proceed backward until all the notices are corrected.  

20. Correction to old Charts: “ Cumulative List of Admiralty Notices to Mariners” is published every 6 months and lists correction numbers affecting each chart for the last 2 years. This should be used to verify that all corrections affecting a particular chart have been carried out. It also gives the date of issue of the current edition of each chart.

21. Correction to old Charts: Temporary and Preliminary (T & P) notices are corrected in the following way: Only voyage charts to be corrected. Look up the list of T’s and P’s in force (This is published monthly in ANM) The T & P notices are printed on one side of the page. This is to facilitate them being cut out and filed, by area in the ship’s T & P file.  The index of this file should be the “Monthly T & P’s in force” list.  This has to be renewed monthly when the new one is received. Correct voyage charts with the T’s & P’s in force, in pencil , and note the correction number in the bottom left-hand corner of the chart, as well as in the correction log.

22. Navigation Warnings in Force: Usually, only the voyage charts are corrected for Navigation Warnings. A proper log of all Navigation Warnings should be maintained with individual sections for each area. The log is maintained in the following way: 1. All Navigation Warnings in force until the year-end are published in the Annual Notices to Mariners. 2. All relevant sections of Navigation Warnings are removed from Admiralty Notices to Mariners and filed in the Navigation Warnings log in serial order.

23. Navigation Warnings in Force: 3. A complete list of all navigation warnings in force is published quarterly, in the weekly notices to mariners. This list forms the first page of the log. 4. The above list is kept updated, as the new notices are received. Old lists are removed on receipt of a new list at the end of the quarter. 5. Obsolete or canceled notices are removed from the log, as required. 6. All Nav warnings are removed at the end of the year when new Annual Notices to Mariners received. 7. Navigation Warnings in force must be corrected on voyage charts in pencil and number to be noted in the left-hand corner of the chart also in pencil.

24. Navigation Warnings in Force: 3. A complete list of all navigation warnings in force is published quarterly, in the weekly notices to mariners. This list forms the first page of the log. 4. The above list is kept updated, as the new notices are received. Old lists are removed on receipt of a new list at the end of the quarter. 5. Obsolete or canceled notices are removed from the log, as required. 6. All Nav warnings are removed at the end of the year when new Annual Notices to Mariners received. 7. Navigation Warnings in force must be corrected on voyage charts in pencil and number to be noted in the left-hand corner of the chart also in pencil.

25. THAT’S ALL THANK YOU!