Introduction
Geographical information (GI) today is vital for the functioning of modern society. Its use is essential for almost all decisions concerning infrastructure development and maintenance, trade, and a large number of other socio-political and economic matters relating to the administration of territory. Geographical information is only of use when it is reliable, timely, accurate, appropriate, and presented to the right person at the right time and in the right manner. Under such conditions, geographical information (GI) becomes a resource, of great value to an organization.
Computer-based geographical information systems (GIS) are increasingly being used in order to assist in the process of capturing spatial data, storing and retrieving them, processing relevant information from them, and making this information available as required. The use of GIS, therefore, has great potential to optimize the value of information as a resource within an organization. The application of GIS technologies and methods to problems of coastal zone management embodies many of these difficulties, and it has even been suggested that, to date, any success that has been achieved in harnessing GIS to the solution of coastal issues has often been reached almost in spite of, rather than because of, the current state-of-the-art in operational geoinformation systems (Bartlett, 1993a).
We all are familiar with land –based maps and its application in GIS environment supported by aerial photography and Remote Sensing. As in the land based GIS application, Marine GIS application requires input in the form of a map of the water area. The input is a Nautical Chart or a Navigation Chart; the use of Nautical Chart at sea by the mariners for navigating at sea is a typical example of GIS in Marine environment. On the land we can move around without the aid of map but Navigation at Sea requires safety under IMO/IHO regulations, which is provided to mariners in the form of a Navigational Chart showing various aid to Navigation and Symbols for safe navigation.With greater quantities of marine and coastal data being acquired today there is an urgent need to evolve information technologies used in these fields.
Marine GIS system is a new type of digital information system with the capability to combine a wide range of four-dimensional oceanographic and coastal data to create environmental scenarios adaptable to a wide range of uses. It is based on the proven methodology of the Electronic Chart Display and Information System (ECDIS), which has been developed for navigational purposes.
The roles and objective of Hydrographic Service
Hydrographic applications in marine coastal development and environmental preservation, is a growth area, the world over. According to an UN study, approximately 50% of the coastal states have no hydrographic capabilities. Another 25% have only limited capabilities. Only the remaining 25%, including India, have adequate hydrographic capabilities. Therefore there is immense scope among the hydrographic offices to conserve/protect our coastal regions and develop and evolve spatial technologies for less developed. The Hydrographic Offices of the world have the responsibility towards their maritime states to provide an essential service within the national transport infrastructure. Hydrographic Services support safe and efficient navigation, foster national maritime development, help to safeguard life and property at sea, facilitate the protection of the marine environment and support the administration and sustainable development of the national maritime zones. A Hydrographic Office plays this multidisciplinary role. These Important roles can be listed as follows:
1. To collect, with systematic surveys at sea and along the coast, georeferenced data related to:
- Coastal configuration, including man made infrastructure for maritime navigation (Aids to navigation and port configuration)
- Depths of the seas in the area of national interest (including all potential hazards to navigation and other marine activities.
- Sea bottom composition
- Tides, currents
- Physical properties of the water column
- Gravity and Magnetic Observations at Sea
2. To process the information collected in order to create organized databases capable of feeding the production of thematic maps, nautical charts and other types of documentation for the following most common
uses :
- Maritime navigation (and traffic control);
- Naval operations;
- Coastal management and defence;
- Marine environment preservation;
- Exploitation of marine resources and laying of Submarine cables/pipelines
- Maritime boundaries definition (Law of the Sea implementation);
- Scientific studies connected to the sea and near-shore zone.
3. To update the databases through re-survey when and where needed,gathering supplementary information from other maritime authorities.
4. To ensure the production, distribution and updating of charts and Electronic navigational Charts(ENC)
5. To ensure the timely dissemination of maritime safety information.