Science / Marine Biology / Hydrographic: Referring to the arrangement and movement of bodies of water, such as currents and water masses

International Hydrographic Organization

Science / Tides and Currents / International Hydrographic Organization: An institution consisting of representatives of a number of nations organized for the purpose of coordinating the hydrographic work of the participating governments. It had its origin in the Internati MORE

Hydrographic Datum

Science / Tides and Currents / Hydrographic Datum: A datum used for referencing depths of water and the heights of predicted tides or water level observations. Same as chart datum. See datum. MORE

Tidal Zoning

Science / Tides and Currents / Tidal Zoning: The practice of dividing hydrographic survey area into discrete zones or sections, each one possessing similar tidal characteristics. One set of tide reducers is assigned to each zone. Tide reducers a MORE


Science / Tides and Currents / ZO: Symbol recommended by the International Hydrographic Organization to represent the elevation of mean sea level above chart datum. MORE

Datum (Vertical)

Science / Tides and Currents / Datum (Vertical): For marine applications, a base elevation used as a reference from which to reckon heights or depths. It is called a tidal datum when defined in terms of a certain phase of the tide. Tidal datums are MORE

Mean Low Water Springs (MLWS)

Science / Tides and Currents / Mean Low Water Springs (MLWS): A tidal datum. Frequently abbreviated spring low water. The arithmetic mean of the low water heights occurring at the time of spring tides observed over the National Tidal Datum Epoch. It is usually d MORE