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Modeling Location
Published in Krzysztof W. Kolodziej, Johan Hjelm, Local Positioning Systems, 2017
Krzysztof W. Kolodziej, Johan Hjelm
Hydrography, according to the Department of Defense Glossary of Mapping, Charting, and Geodetic Terms, is “the science which deals with the measurements and description of the physical features of the oceans, seas, and lakes, and their adjoining coastal areas, with particular reference to their use for navigational purposes.” Hydrographic data have an important geospatial component. Two well-known systems of feature class definitions used to describe features within the hydrographic discipline are the S-57 Object Catalog and the Feature and Attribute Coding Catalog (FACC). The S-57 Object Catalog is part of the IHO Transfer Standard for Digital Hydrographic Data, developed by the International Hydrographic Organization. The FACC is part of the Digital Geographic Exchange Standard (DIGEST) developed through an international cooperative effort by the member nations of the Digital Geographic Information Working Group (DGIWG).
Hydrographic Surveys in Tidal Rivers
Published in S.N. Ghosh, Tidal Hydraulic Engineering, 2017
A hydrographic survey usually consists of determination of the following types of data: (i) topography of the bottom, (ii) heights and times of tides and water stages and (iii) location of fixed objects for survey and navigational purposes. In general a hydrographic survey means the procedure of measuring the depth of water in a river or sea utilising a boat or survey ship as a working platform while simultaneously determining the horizontal position of the boat relative to the near-by shoreline and prominent natural or man-made objects.
Electronic charts
Published in Laurie Tetley, David Calcutt, Electronic Navigation Systems, 2007
In 1683 an official survey of British waters was initiated by Royal Command, although the surveys that were published some 10 years later were produced at the surveyor's expense. In the 18th century much hydrographic work around the world was done by British hydrographers, although they still had to have their work published at their own expense, gaining recompense only by selling the results of their efforts privately. It was not until 1795 that the office of Hydrographer to the Board of Admiralty was established, the French having established their Hydrographic Office some 75 years earlier. The United Kingdom Hydrographic Office (UKHO), as it is now called, has an enviable reputation as a supplier of high quality charts and provides worldwide coverage with a folio of some 3300 charts. The UKHO is a member of the International Hydrographic Organization (IHO), a body set up to coordinate the activities of national hydrographic offices, promote reliable and efficient hydrographic surveys and ensure uniformity of chart documentation.
A marine spatial data infrastructure in New Zealand: a systematic review on the cost-benefits
Published in Journal of Spatial Science, 2019
Edward Griffin, Andy Coote, Joep Crompvoets
Hydrographic services gather reliable and up-to-date information vital for charts and safe navigation. Recently it has been recognised that hydrographic information goes beyond the traditional mariner and is relevant for a range of other groups and activities (Connon and Nairn 2010, International Hydrographic Organization 2011a). For example government agencies, coastal managers, engineers and scientists can use hydrographic data to benefit activities such as tourism, commercial shipping, fishing, scientific research and coastal zone management. Technological changes in ocean mapping, e.g. high-accuracy sensors available to modern-day surveys, can be used for maintaining a sufficient channel depth in ports to attract cruise ships for tourism and encourage container-ship traffic, and the data are also of sufficient quality for coastal management (Holland et al. 2016).
Hydrodynamic study of flapping foil propulsion system fitted to surface and underwater vehicles
Published in Ships and Offshore Structures, 2018
Naga Praveen Babu Mannam, Parameswaran Krishnankutty
The autonomous underwater vehicles (AUVs) are very much in use for exploring subsea natural resources, monitoring marine pollution, performing hydrographic surveys, etc. Many countries have developed AUVs of different types and are focusing further on the research and development of AUVs with improved performance. Energy for AUV operations is taken from battery cells on board. Thus, endurance of the AUV operation and the provision of type and number of sensors on board are practically limited due to the restricted energy available from the battery. The energy consumption can be reduced by providing the AUVs with a propulsion system which is more efficient than the conventional screw-type thrusters. Flapping foil propulsion is more efficient (about 80%) than the conventional screw propulsion system (around 60%) (Anderson et al. 1998). Use of flapping foils also disturbs the water less compared to screw propellers, thus making it more environment-friendly and creates less noise (improved stealth characteristics). With these perspectives under consideration, the present paper reports the experimental and computational studies carried out on an underwater vehicle (UV) fitted with a pair of foils at the forward side, one on each side (port and starboard) of the body, and a single fin at the aft end, resembling the arrangement of pectoral fins and caudal fin of a thunniform fish (e.g. tuna fish) and also the case of a surface ship model fitted with tail fin. The forward (pectoral) fins have the freedom to oscillate about the longitudinal axis of the fin joint and/or rotate about the transverse axis and the aft (tail) fin has the freedom to oscillate in the horizontal plane about the vertical axis.