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The Medieval and Early Modern Nautical Chart: Birth, Evolution and Use, Lisbon-based ERC-funded academic project. They develop and maintain the MEDEA-CHART Database, a sophisticated search engine and aggregator of early nautical charts data. Online version of Chart No.1 with "Symbols, Abbreviations and Terms" used in nautical charts
A sailor and a man on shore, both sounding the depth with a line. Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditionally shown on nautical charts in fathoms and
A chart datum is the water level surface serving as origin of depths displayed on a nautical chart and for reporting and predicting tide heights. A chart datum is generally derived from some tidal phase, in which case it is also known as a tidal datum. [1] Common chart datums are lowest astronomical tide (LAT) [1] and mean lower low water (MLLW).
Nautical mile: Length: Rhumb: Angle: The angle between two successive points of the thirty-two point compass (11 degrees 15 minutes) (rare) [1] Shackle: Length: Before 1949, 12.5 fathoms; later 15 fathoms. [2] Toise: Length: Toise was also used for measures of area and volume Twenty-foot equivalent unit or TEU: Volume: Used in connection with ...
An Electronic Navigational Chart (ENC) is a digital representation of a real-world geographical area for the purpose of Marine navigation.Real-world objects and areas of navigational significance, or to a lesser degree - informational significance, are portrayed through Raster facsimiles of traditional paper charts; or more commonly through vector images, which are able to scale their relative ...
Portolan charts are nautical charts, first made in the 13th century in the Mediterranean basin and later expanded to include other regions. The word portolan comes from the Italian portolano , meaning "related to ports or harbors ", and which since at least the 17th century designates "a collection of sailing directions".
A fathom line or fathom curve, a usually sinuous line on a nautical chart, joins all points having the same depth of water, thereby indicating the contour of the ocean floor. [24] Some extensive flat areas of the sea bottom with constant depth are known by their fathom number, like the Broad Fourteens or the Long Forties, both in the North Sea.
Between 1906 and 1916, Heck expanded the capability of wire-drag systems from a relatively limited area to sweeps covering channels 2 to 3 nautical miles (3.7 to 5.6 km; 2.3 to 3.5 mi) in width. [15] The wire-drag technique was a major contribution to hydrographic surveying during much of the rest of the 20th century.