Chart

CHART, n. A hydrographical or marine map; a draught or projection of some part of the earths superficies on paper, with the coasts, isles, rocks, banks, channels or entrances into harbors, rivers, and bays, the points of compass, soundings or depth of water, _c., to regulate the courses of ships in their voyages. The term chart is applied to a marine map; map is applied to a draught of some portion of land.

A plan chart is a representation of some part of the superficies of the globe, in which the meridians are supposed parallel to each other, the parallels of latitude at equal distances, and of course the degrees of latitude and longitude are every where equal to each other.

Mercators chart, is one on which the meridians are straight lines, parallel and equidistant; the parallels are straight lines and parallel to each other, but the distance between them increases from the equinoctial towards either pole, in the ratio of the secant of the latitude to the radius.

Globular chart, is a meridional projection in which the distance of the eye from the plane of the meridian, on which the projection is made, is supposed to be equal to the sine of the angle of forty-five degrees.

Selenographic charts, represent the spots and appearances of the moon.

Topographic charts, are draughts of particular places, or small parts of the earth.