Bathymetric chart

A bathymetric chart is a type of isarithmic map that depicts the submerged topography and physiographic features of ocean and sea bottoms. Their primary purpose is to provide detailed depth contours of ocean topography as well as provide the size, shape and distribution of underwater features. Topographic maps display elevation above ground and are complementary to bathymetric charts. Charts use a series of lines and points at equal intervals to showcase depth or elevation. A closed shape with increasingly smaller shapes inside of it can indicate an ocean trench or a seamount, or underwater mountain, depending on whether the depths increase or decrease going inward. Bathymetric surveys and charts are associated with the science of oceanography, particularly marine geology, and underwater engineering or other specialized purposes. Bathymetric data used to produce charts can also be converted to which are vertical sections through a feature. Bathymetry#History Ancient Egypt The use of bathymetry and the development of bathymetric charts dates back around the 19th century BC to ancient Egypt. Depictions on tomb walls such as the bas-relief carvings of Deir al-Bahri commissioned by Queen Hatshepsut in the 16th century BC show ancient mariners using long slender poles as sounding poles to determine the depth of the Nile River and into the Nile River Delta. Ancient Greece The first written account and mapped records of sounding did not occur until 1000 years after the Egyptians had begun sounding and mapping the Nile. The Greek historian Herodotus writes of a sounding in 66 feet of water of the mouth of the Nile in the river delta. He writes of yellow mud being brought up similar to the same that was deposited with the yearly floods. These accounts show a heightened awareness of regional depths and seafloor characteristics among ancient mariners and demonstrate that discoveries in bathymetry and the use of bathymetric charts had progressed significantly. The New Testament recounts soundings being taken with the shipwreck of Paul on the island of Malta in the Book of Acts.

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Contour line

A contour line (also isoline, isopleth, isoquant or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function parallel to the -plane. More generally, a contour line for a function of two variables is a curve connecting points where the function has the same particular value. In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level.

Bathymetry

Bathymetry (bə'θɪmətri; ) is the study of underwater depth of ocean floors (seabed topography), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water depth measurements are from Ancient Egypt over 3000 years ago. Bathymetric charts (not to be confused with hydrographic charts), are typically produced to support safety of surface or sub-surface navigation, and usually show seafloor relief or terrain as contour lines (called depth contours or isobaths) and selected depths (soundings), and typically also provide surface navigational information.

Topography

Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary science and is concerned with local detail in general, including not only relief, but also natural, artificial, and cultural features such as roads, land boundaries, and buildings.

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Giovanni De Cesare, Azin Amini, Jean-Noël Saugy

The 3rd correction of the Rhône River is the largest flood protection project in Switzerland so far. Covering a length of 162 km, it aims to protect some 100,000 people and prevent flood damages, which could raise up to 10 billion Swiss francs for major ev ...

ETH Zurich, Laboratory of Food Process Engineering2021

Bathymetry and latitude modify lake warming under ice

Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Tomy Doda, Cintia Luz Ramon Casanas, Kraig Bates Winters

In late winter, solar radiation is the main driver of water motion in ice-covered lakes. The resulting circulation and mixing determine the spatial distribution of heat within the lake and affect the heat budget of the ice cover. Although under-ice lake wa ...

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SODIS potential: A novel parameter to assess the suitability of solar water disinfection worldwide

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This paper studies the worldwide applicability of solar water disinfection (SODIS) technology through a novel parameter: the SODIS potential. This parameter is defined as the inverse ratio between the required exposure time to achieve a four log disinfecti ...

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