Chart, a marine or hydrographical map, exhibiting a portion of a sea or other water, with the islands, coasts of contiguous land, soundings, currents, &c. (see MAP). Chart-making has been traced back to about the beginning of the 13th century; now most civilised countries have their system of charts. In the English service, when coasts have been surveyed by the Admiralty, charts are engraved, and are sold at various prices, from 3s. down to 6d. each. This price is below their cost, the object being to encourage their general use as much as possible. The navigating charts, showing the dangers of coasts with sufficient clearness to enable mariners to avoid them, are generally on the scale of half an inch to a mile; those of larger size show all the intricacies of the coast. The merchant-service is supplied with charts by agents, who receive a stock from the Admiralty, and keep them on sale. The preparation of charts is part of the duty of the Hydrographical Department at the Admiralty. In the financial year as represented in the national estimates, a sum of about £14,000 is provided for the branch that takes charge of the engraving of the charts, irrespective of the surveying, which always costs a much larger sum. The Admiralty sells annually some 140,000 charts, besides supplying the navy gratis. Several ships of the navy, besides colonial gunboats and hired steamers, are usually engaged in examining and charting seas and coasts. See GEOGRAPHY, SEA, SOUNDING, CHALLENGER EXPEDITION, &c.
The United States coast survey, a vast undertaking, was begun in 1807, carried on intermittently till 1845, and since then more systematically, save during the civil war, under Professor Bache and his successor, Professor Pierce. In the American service, the coasts of the United States are surveyed and the charts produced by the coast and geodetic survey attached to the Treasury Department, and the unsurveyed foreign coasts are surveyed by the Bureau of Navigation, the charts being produced by the Hydrographic Office, Navy Department. The coast and geodetic charts are sold at from 10 cents to $1 each, being the cost of printing and paper. Naval vessels are supplied free. The charts are obtainable at coast and geodetic survey agencies at all seaports of the United States. They exhibit accurate and minute topography as far inland as will supply landmarks for the navigator, or serve for purposes of defence; the shore line at high-water and sanding to mean low-water; soundings, contours, and material of bottom at different depths; bars, channels, sailing ranges and directions; true meridian and compass variation, rocks, reefs, buoys, beacons, lights; tide establishment; detailed explanation of lighthouses and signal stations. They are carefully corrected for every substantial change in any of those features. They range in scale from (30,401 inches to the nautical mile) to ( of an inch to the nautical mile), and comprise sailing charts exhibiting vast areas, general charts, coast charts, and harbour charts.
The term chart is also given to a graphical representation, by curves or otherwise, of the fluctuations of any varying magnitude—temperature, barometric pressure, population, prices, &c. See GRAPHIC METHODS, TEMPERATURE, STORMS, &c.