Victor Olerskiy served as Deputy Minister of Transport of the Russian Federation. He was also Head of the Federal Agency for Maritime and River Transport from 2016 to 2018. This article will look at nautical charts, exploring some of their most common features and how data is gathered.
The term 'nautical charts' is often used to describe navigational charts, which are essentially maps of the world's oceans and waterways. They are rather different to a conventional roadmap since the oceans do not have cities, towns, streets or roads.
A marine chart is more akin to a topographical map that shows the contour of the land in addition to the shapes and heights of mountains, hills and other geographic features. As the name would suggest, nautical charts tend to focus on what is going on beneath the waves, detailing depths, ridges, shallows, islands and similar features. This information is crucial to a sailor, providing him or her with vital information about the layout beneath the ocean surface, enabling them to navigate safely and avoid hazards lurking beneath them.
Unlike road maps, nautical charts include extensive details about navigation aids, including information on lighthouses, daymarks, buoys and other fixtures created to mark dangerous waters and help seafarers find their position.
Nautical charts are available in both paper and electronic formats today.
On a nautical chart, water depths are represented by numbers. Depth measurements are generally acquired via hydrographic surveys. Depths may be in either fathoms or feet, and the chart will indicate which. A nautical unit of measurement, a fathom is equal to six feet.
Water depths may be connected with a line called a depth contour on a nautical chart. Depth contours are similar to the topographical lines often incorporated in regular land maps, essentially providing mariners with a picture of the bottom of the seabed.
Hydrographic surveys are a time-consuming, laborious process that involves gathering hydrographic data. Nevertheless they are incredibly important, as a dated nautical map could be unreliable. Depths are measured in several ways. Historically, cartographers used a sounding line, but more recently, echo sounding has become the go-to method of measuring the seabed in the open ocean.
The international chart series is a global system of nautical charts coordinated by the International Hydrographic Organization. The scheme was developed with the goal of unifying as many chart systems as possible, eliminating uncertainties. While charts published by commercial publishers often carry additional information of particular interest, for example, information relevant to yacht skippers, only charts issued by national hydrographic offices are deemed 'official'.