Accuracy of bathymetric data in electronic navigational charts

• Autorzy: Weintrit A.

Identyfikatory

DOI

10.17402/302

• Języki publikacji: EN

Abstrakty

EN

Navigational charts are essential tools for marine navigation. But how accurate are the navigational charts that we use when going sailing? Do we really know how much faith can be placed in them? All charts, whether paper or electronic, contain data, which varies in quality due to the age and accuracy of individual surveys. In general, remote areas away from shipping routes tend to be less well surveyed, and less frequently, while areas of high commercial traffic are re-surveyed frequently to very high levels of accuracy, particularly where under-keel clearances are small. It is quite accurate to consider a chart as a jigsaw of individual surveys pieced together to form a single image. Having the necessary skills to determine how much confidence should be placed in the surveys, which combine to form a chart, should be a requirement for any sailor venturing into unfamiliar waters. When the International Hydrographic Organization (IHO) developed the S-57 standard for Electronic Navigational Charts (ENCs), this problem was recognized and it was decided that the quality of survey data used to compile ENCs had to be encoded within a composite data quality indicator ‘Category of Zone of Confidence’ (CATZOC) to assist seafarers in assessing hydrographic survey data and the associated level of risk of navigating in a particular area. According to IHO S-67, the accuracy of Electronic Navigational Charts is not impressive and leaves much to be desired. The author discusses these apparent shortcomings of ENCs and present erroneous approaches to this problem, so common in the seafaring community.

Słowa kluczowe

EN

marine navigation; safety at sea; international hydrographic organization; ECDIS; electronic navigational charts; accuracy; category of zone of confidence (CATZOC)

• Wydawca: Wydawnictwo Naukowe Akademii Morskiej w Szczecinie
• Czasopismo: Zeszyty Naukowe Akademii Morskiej w Szczecinie
• Rocznik: 2018
• Tom: nr 55 (127)
• Strony: 60--69
• Opis fizyczny: Bibliogr. 13 poz., rys., tab.

Twórcy

autor

Weintrit A.

• Gdynia Maritime University, The Faculty of Navigation 3 Jana Pawła II Ave., 81-345 Gdynia, Poland

Bibliografia

• 1. Dorts, L. (2014) Charting a dynamic seafloor: how an excellent survey becomes a poor data set, and what to tell the marine. Lighthouse, Journal of the Canadian Hydrographic Association, Edition 82.
• 2. Gladisch, S., Ruth, T. & Jonas, M. (2017) Improving Uncertainty Visualisation in ENCs. Towards a Better Portrayal of Bathymetric Data Quality for Mariners. Hydro International 01/02/2017.
• 3. IHO S-4 (2017) Regulations of the IHO for International (INT) Charts and Chart Specifications of the IHO. Edition 4.7.0, International Hydrographic Organization, Monaco, July.
• 4. IHO S-44 (2008) IHO Standards for Hydrographic Surveys. International Hydrographic Organization, Monaco, February.
• 5. IHO S-57 (2014) IHO Transfer Standard for Digital Hydrographic Data. Supplementary Information for the Encoding of S-57 Edition 3.1 ENC Data. Supplement No. 3 to Edition 3.1, IHO, Monaco, June.
• 6. IHO S-67 (2017) Mariners’ Guide to Accuracy of Electronic Navigational Charts (ENC). Edition 0.4, International Hydrographic Organization, Monaco, April.
• 7. IHO S-100 (2017) Universal Hydrographic Data Model. Edition 3.0.0. International Hydrographic Organization, Monaco, April.
• 8. Kartverket (2017) The Norwegian Mapping Authority [Online] Available from: https://kartverket.no/en/EFS/ Miscellaneous-Notices-to-Mariners/1-Important-attachments-to-Efs/15-Zones-of-Confidence--ZOC-diagram/– Kartverket [Accessed: February 27, 2018]
• 9. Mellor, T. (2017) Category Zones of Confidence (CATZOC) – dispelling the myths. Blog, 16 March 2017, https: //www.admiralty.co.uk/news/blogs/category-zones-of-confidence
• 10. Powell, J. (2011) The New Electronic Chart Product Specification S-101: An Overview. TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation 5, 2, pp. 167–171.
• 11. Weintrit, A. (2009) The Electronic Chart Display and Information System (ECDIS). An Operational Handbook. A Balkema Book. CRC Press, Taylor & Francis Group, Boca Raton – London – New York – Leiden.
• 12. Weintrit, A. (2018) Reliability of navigational charts and confidence in the bathymetric data presented. Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie 54 (126), pp. 84–92.
• 13. Wyllie, K., Cole, M., Froelich, G., Wilson, M., Nelson, K., Brennan, R. & Newman, T. (2017) Developing a Method to Validate the Navigational Bathymetric Database. US HYDRO, Galveston, Texas USA, 20 March.