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Gerardus Mercator
Gerardus Mercator , Latin form of Gerhard Kremer , 1512-94, Flemish geographer, mathematician, and cartographer. He studied in Louvain , where he had a geographical establishment (1534). From 1537 to 1540 he surveyed and mapped Flanders . In 1538 he produced his first map of the world (based on...
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map projection
map projection transfer of the features of the surface of the earth or another spherical body onto a flat sheet of paper. Only a globe can represent accurately the shape, orientation, and relative area of the earth's surface features; any projection produces distortion with regard to some of these ...
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astrolabe
astrolabe , instrument probably used originally for measuring the altitudes of heavenly bodies and for determining their positions and movements. Although its origin is ancient and obscure, its invention is frequently ascribed either to Hipparchus or to Apollonius of Perga. For many centuries it was...
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Giovanni da Verrazano
Giovanni da Verrazano , c.1480-1527?, Italian navigator and explorer, in the service of France, possibly the first European to enter New York Bay. Sailing west to reach Asia, Verrazano explored (1524) the North American coast probably from North Carolina to Maine. In 1526, or later, sailing from Fra...
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scale
scale in cartography, the ratio of the distance between two points on a map to the real distance between the two corresponding points portrayed. The scale may be expressed in three ways: numerically, as a ratio or a fraction, e.g., 1:100,000 or 1/100,000 ; verbally, e.g., "one inch to one mile...
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Adriaen Block
Adriaen Block fl. 1610-24, Dutch navigator. Eager to establish a fur trade with the Native Americans, Amsterdam merchants sent (1613) Block and another Dutch navigator to explore the region discovered by Henry Hudson. After wintering near Albany, Block sailed from the Hudson into Long Island Sound ...
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George William Blunt
George William Blunt 1802-78, American hydrographer; son of Edmund March Blunt, a pioneer publisher of nautical books and charts in Newburyport, Mass. He established (1821) himself in a similar business in New York and published the numerous editions of Bowditch's Navigator, Blunt's Coast Pilot, ...
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contour
contour or contour line, line on a topographic map connecting points of equal elevation above or below mean sea level. It is thus a kind of isopleth, or line of equal quantity. Contour lines are drawn on maps with a uniform interval of vertical distance separating them (usually 10, 20, 50, or 1...
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chart
chart term referring to maps prepared for marine navigation and for air navigation. All charts show, in some convenient scale , geographic features useful to the navigator, as well as indications of direction, e.g., true north (the direction of the geographic North Pole), magnetic north (the dir...
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map
map conventionalized representation of spatial phenomena on a plane surface. Unlike photographs, maps are selective and may be prepared to show various quantitative and qualitative facts, including boundaries, physical features, patterns, and distribution. Each point on such a map corresponds to a ...
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