A nautical chart is a scaled representation of a geographic area, showing navigable waters and adjacent coasts. It is an essential tool for identifying navigational aids and plotting courses.
Nautical charts represent a defined navigational area and identify aids and dangers to navigation: buoys, reefs, shallows, traffic lanes, cardinal directions, etc. Charts are used aboard all types of vessels: ships, yachts, fishing boats, etc.
Nautical charts can be paper or electronic. The Mercator projection is the most common of the many different types. Polar projection charts also may be used in very high latitudes. Nautical charts must be updated regularly to account for the constant changes in navigational aids.
The fundamental criterion is the part of the globe to be sailed.
