Hydrography involves measuring the depth of the water and fixing the position of all the navigational hazards that lie on the seafloor, such as wrecks and rocks. This is done mainly with specialised ships and boats operating echo sounders and sonars, but also using survey aircraft fitted with lasers. Useful information can also be derived sometimes from satellite observations. Hydrography also involves measuring the tide and the currents.
The Importance of Hydrography
In addition to supporting safe and efficiient navigation of ships, hydrography underpins almost every other activity associated with the sea, including:
resource exploitation - fishing, minerals, ...
environmental protection and management
maritime boundary delimitation
national marine spatial data infrastructures
recreational boating
maritime defence and security
tsunami flood and inundation modelling
coastal zone management
tourism
marine science
Source:
https://www.iho.int/srv1/index.php?option=com_content&view=article&id=302&Itemid=290&lang=en
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