Charts help captains of ships and pilots of airplanes navigate to their destination quickly and safely. They are like maps, but for the sea and air. There are two kinds of charts: nautical charts and aeronautical charts.

Nautical charts feature information about the sea, such as depth and behavior of the water in particular areas. Nautical charts detail where swells, tides, and ocean gyres develop. Nautical charts also represent features of the sea floor, such as canyons and reefs. They may contain the locations of man-made features such as buoys, lighthouses, and harbors. Sea captains use this information to plan their routes. They also use the charts to determine the location of their ship.

Aeronautical charts show features of the land such as mountain ranges, bodies of water, tall buildings, airports, and safe landing areas for pilots. They also show the distance between certain points and the official airspace of different countries. Aeronautical charts typically display different radio frequencies for the areas they depict, so pilots can call for assistance in an emergency or bad weather. These charts help pilots navigate their airplanes and determine a safe flying altitude.

Both types of charts include information about the Earths magnetic field. This is important because equipment can experience irregularities as vessels approach the magnetic north pole or the magnetic south pole.

Most charts are printed on large sheets of paper and come in different scales. Some charts depict a very small area, such as the coastline around a harbor. Others depict an entire ocean or continent. There are also electronic charts, created using a geographic information system (GIS). GIS charts are stored on computers.