Bathymetry is a notion that is formed from the Greek word bathýs (which can be translated as “deep”) and the suffix metria. The concept is used in the field of geology to refer to the analysis of the deep sea.
Bathymetry is analogous to altimetry: while the first is in charge of studying the depths, the second is focused on the heights. Bathymetry experts are in charge of drawing isobath maps (curves that cartographically represent points of identical depth in large lakes and seas). In addition to these maps, specialists also study the distribution of living beings in isobatic regions.
It can be said that bathymetry is responsible for drawing maps (bathymetric maps) to present information on the ocean or lake bottom, measuring depths. Originally, a cable with a great weight was lowered from a boat: when it reached the bottom, the measurement was carried out. This method only allowed measuring depth at a single point and its results were subject to currents, tides and other variables.
At present, bathymetry uses a sonar that is installed on a ship and that emits sound waves towards the bottom of the ocean. Depth measurement is done through the time it takes for sound to sink to the bottom, bounce back, and return to the device. Along with sonar, it is common to use GPS systems that report the exact location of the vessel in question.
Other data of interest, in addition to those already exposed, on bathymetry are some like these:
-It is considered that the origin of what are bathymetric measurements are in Ancient Egypt. At that time, what they did to carry them out was to use a stone tied to a rope.
-Until the appearance of GPS systems to undertake bathymetry, this consisted of two types of work: planimetry, on the one hand, and on the other, what is known as classical topography or altimetry.
No less relevant is to be clear that there are various types of bathymetry, which are fundamentally based on the systems or tools they use. Among the most significant we can highlight the following:
-Bathymetry using laser. As its name suggests, it uses a laser system and has the peculiarity that it can study depths between 2 and 30 meters.
-Photogrammetric bathymetry, which has the peculiarity of being used for areas with very shallow waters.
-Bathymetry by remote sensing. This is considered to be one of the systems that has managed to obtain really satisfactory and effective results in what are shallow seas. It achieves this because it uses satellites such as SPOT, GEOSAT or RADARSAT.
-Bathymetry by photographic procedures. It is also used for shallow areas and is based on the study of what is the variation of the visible spectrum.