IHO Data Quality Survey26/04/2011
|The International Hydrographic Organisation (IHO) Data Quality Working Group (DQWG) has produced a questionnaire in an attempt to gauge the marinerís current perception of data quality. The questionnaire provides the mariner with an opportunity to give feedback on existing methods of representing data quality and to comment on a range of new concepts put forward by the DQWG.|
Mariners having experience in using navigational charts and products and would like to participate in the questionnaire, an on-line version can be found at https://www.surveymonkey.com/s/IHODQWG .
All bathymetric datasets, regardless of the method of acquisition, contain a level of uncertainty with regards to their accuracy. With modern positioning systems, sophisticated echo sounders and tide gauges, the quality of these datasets is better than ever before. However, when we come to use this data in the production of navigational charts, we are placing it next to data that may have been collected using a leadline and sextant. This can pose a problem for the user of the chart, the mariner, who when faced with a mass of soundings must make a judgement as to which ones he can trust and which ones he can’t.
In the early 1970s the first source diagrams appeared on British Admiralty Charts. This represented the first real attempt to provide the Mariner with a means of judging the quality of the underlying survey data by delimiting the zones where different surveys had been used in the compilation. Unfortunately, despite the presence of a source diagram, marine accidents still occur where vessels navigate in areas where the underlying survey is not of sufficient quality. On the 8th September 2006 the jack-up barge, Octopus, towed by the tug Harald, ran aground in Stronsay Firth, Orkney Islands, causing over £1m worth of damage. The Marine Accident Investigation Board suggested that whilst the Captain of the tug should have made better use of the source diagram, “Relevant IHO/IMO working groups should investigate ways of ensuring that ECDIS displays provide a clear warning or indication to the mariner whenever the survey data used to produce the electronic chart in use is of poor quality.”
The International Hydrographic Organisation (IHO) Data Quality Working Group (DQWG) originally established in 2005 was reformed in 2007 to investigate how the quality of hydrographic survey data could be better presented to the mariner. It is widely accepted that the current methods of representing data quality to the mariner rely too heavily on an understanding of the relevance of quality indicators such as survey date and acquisition method. In the case of Electronic Navigational Charts (ENCs), the mandatory S-57 quality attribute CATZOC (Category of Zone of Confidence), represents the quality of the survey data in a specific area in terms of positional accuracy, depth accuracy and seafloor coverage. However, CATZOC only gives an impression of the quality of the bathymetric data at the time of survey. In areas of high seabed mobility a Mariner could be easily mislead by seemingly good quality data which no longer represents the true nature of the seabed. The issue is confused further by a lack of consistency in the way in which ENC producers determine CATZOC values for legacy surveys they use in their products.
The deadline for participation in the questionairre is 27th May 2011.
comments powered by Disqus
Read more about:
data Current ECDIS bathymetric data Positioning
Supplier: International Hydrographic Bureau (IHB), International Hydrographic Organization (IHO)
More news from this supplier:
Abstracts Sought for 8th ABLOS Conference
An Edition of EIHC to Build on
E-IHC Providing Stakeholder Insights
Monaco Heads Towards Fifth E-IHC
WHD 2014: Hydrography Ė Much More Than Just Nautical Charts
MACHC Meeting Emphasises Importance of Supporting Hydrographic Survey
Joint IHO/FIG Stakeholders of Capacity Building Conference
Yves Guillam Appointed as IHB Assistant Director
GEBCO Gazetteer of Undersea Feature Names Now Online
English Version of Manual on Tides Now Available
Korean Success for FastOcean Training
Web and PC Based Navigational Charts App
Ocean Surface Slope Lowers Sea Level in Europe
Workshop on Underwater Sound in Relation to Dredging
Boskalis and Van Oord Creating Room for Jakarta
ArcGIS for Maritime: Bathymetry 10.3 Adds Features
Connectivity Helps Land UFO in North Sea
Offshore Survey 2015 Launches Conference Programme
Kongsberg Sonar and Multibeam Systems for Swedish Submarines
Prof Karen Wiltshire New POGO Chair
Generating Lat/Lon/Depth Files from Echoview
This video shows how to use Echoview to export a CSV file of the water depth as measured by an echosounder.