Hydrographical survey involves the measurement and description of features of the seabed / riverbed, swamps, ponds, dredging site, foreshore structure and the 2.515 HWM line. Registered Surveyor carries out such survey at coastal areas whereas hydrographic surveyor conducts their survey in deep seas for maritime and navigational purposes.Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore oil ...

Topographical helps determine accurately the terrestrial or three-dimensional space position of points and the distances and angles between them using leveling instruments such as theodolites, dumpy levels and clinometers.Topographic surveying is a field of geoscience and planetary science and is concerned with local detail in general, including not only relief but also natural and artificial features, and even local history and culture.Topographic surveying is the mapping of existing natura...