Science / Tides and Currents / Chart Datum: The datum to which soundings on a chart are referred. It is usually taken to correspond to a low-water elevation, and its depression below mean sea level is represented by the symbol Z;. Since 1980, chart datum has been implemented to mean lower low water for all marine waters of the United States, its territories, Commonwealth of Puerto Rico, and Trust Territory of the Pacific Islands. See datum and National Tidal Datum Convention of 1980.
Chart Noun Synonyms: sea-chart, map
Chart Verb Synonyms: plot, plan, map (out), design
Science / Tides and Currents / National Tidal Datum Convention: Effective November 28, 1980, the Convention: (1) establishes one uniform, continuous tidal datum system for all marine waters of the United States, its territories, Commonwealth of Puerto Rico, and Tr MORE
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
Science / Tides and Currents / Gulf Coast Low Water Datum (GCL WD): A tidal datum. Used as chart datum from November 14, 1977, to November 27, 1980, for the coastal waters of the Gulf coast of the United States. GCLWD is defined as mean lower low water when the type o MORE