Mercator, Gerardus

Mercator, Gerardus (jərär`dəs mûrkā`tər), Latin form of Gerhard Kremer (gār`härt krā`mər), 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 Ptolemy's map); in 1541 he made a terrestrial, and in 1551 a celestial, globe. He was appointed (1552) to the chair of cosmography in Duisburg. In 1554 he made a six-sheet map of Europe. The first map using the projection (the translation of the spherical earth to a two-dimensional flat plane) that bears his name appeared in 1569. Accurate in equatorial regions but distorting the size and shape of numerous other areas of the world, the Mercator projection has been more generally used than any other projection for navigators' world maps. In 1585, Mercator began a work (for which he coined the word atlas) that included many of his earlier maps; the atlas was completed by his son and published in 1594. Mercator did cartographical work for Charles V and was cosmographer to the duke of Jülich and Cleves. He wrote several books on subjects such as ancient geography and the science and mathematics of geography and cartography.

Bibliography

See N. Crane, Mercator: The Man Who Mapped the Planet (2003).

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Mercator, Gerardus

 orig. Gerard Kremer

(born March 5, 1512, Rupelmonde, Flanders—died Dec. 2, 1594, Duisburg, Duchy of Cleve) Flemish cartographer. He received a master's degree in 1532 from the University of Louvain (Belgium), where he settled. By 24 he was a skilled engraver, calligrapher, and scientific-instrument maker. He and his colleagues made Louvain a centre for construction of maps, globes (terrestrial and celestial), and astronomical instruments. He was appointed court cosmographer to Duke Wilhelm of Cleve in 1564, and in 1569 he perfected what has become known as the Mercator projection, in which parallels and meridians are rendered as straight lines spaced so as to produce at any point an accurate ratio of latitude to longitude. It permitted mariners to steer a course over long distances, plotting straight lines without continually adjusting compass readings. While the meridians are equally spaced parallel vertical lines, the lines of latitude are spaced farther and farther apart as their distance from the Equator increases; on world maps the projection greatly enlarges areas distant from the Equator.