It is a branch of applied sciences that deals with the measurement and description of the natural and physical properties of the navigable parts of the oceans, seas, coastal areas, lakes and rivers, in addition to studying the expected changes over time, and researching different ways to represent the surface of the sea floor and the coastline and what this bottom contains of natural features. Then it is drawn on a map with a specific scale, provided that the main purpose of this is the safety of maritime navigation and support for all other maritime activities, including economic development, security, defense, scientific research and environmental protection.
The marine survey is considered one of the basic requirements for evaluating the dredging works, an accurate estimate of the volumes that will be dredged, and an accurate assessment of the nature of the materials that will be drilled. Accurate sizing is important for selecting a dredging area, and estimates for productivity, implementation times, and ultimately project costs. Expressed in quantities, up to millions of cubic metres, the depth data is acquired using a single-beam echo instrument (SBES), with the location provided by the Global Positioning System (GPS).