Mercator, Gerardus (1512–1594)

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Mercator, Gerardus (15121594)

A Flemish cartographer who invented a system of setting lines of latitude and longitude on charts of the spherical earth, the Mercator projection, which has become a standard for maps into modern times. Born in Rupelmonde, a small town in Flanders, he studied at the University of Louvain, where he achieved a master's degree in 1532. Troubled by the conflict of ancient Greek philosophy with Christian doctrine, Mercator studied mathematics, philosophy, geography and astronomy in order to reach some conclusions about the origins and true nature of the world. He was above all fascinated by the developing art of mapmaking, which in his day benefited from the discoveries of explorers and traveling merchants. He became a skilled maker of globes and instruments; under the training of Gemma Frisius and Gaspar Myrica, two men expert in the craft, he also mastered the difficult art of engraving. A workshop set up by the three men turned Louvain into an important center of globe making, cartography, and the production of sextants, telescopes, and other scientific instruments. His far-ranging exploration and questioning of accepted Christian doctrines, however, landed him in trouble with the religious authorities, and in 1544 he was arrested, tried, convicted, and briefly imprisoned on a charge of heresy.

In 1552 Mercator moved to Duisburg, in the Germany duchy of Cleves, where he was appointed a professor of mathematics and also became a land surveyor. In Duisburg, where he remained for the rest of his life, he helped to found a grammar school and continued his work in cartography. After publishing a map of Europe in 1554 and then several other local maps of Britain and the European continent, his reputation spread. He also developed a new method of producing globes, in which he pasted on the sphere printed maps that were cut to fit by tapering their edges toward the top and bottom.

Mercator was appointed by the Duke of Cleves as an official court cartographer. He perfected his system of marking parallel lines on a map to indicate degrees of longitude that could be applied to navigation charts and allow ship captains to more accurately follow their course at sea. He first used this system on a map of the world he completed in 1569. In the 1570s he began producing an atlas, a collection that included the maps of the ancient Greek astronomer Ptolemy as well as his own maps covering France, Germany, Italy, the Netherlands, eastern Europe, Greece, and the British Isles. This work, which he completed over the span of more than twenty years, was finally published by his son after his death.

Mercator, Gerardus (or Gerhard Kremer)

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(b. Rupelmonde, Flanders, 5 March 1512; d. Duisburg, Germany, 2 December 1594)


Mercator’s family name was Kremer, but he latinized it on entering the University of Louvain in 1530. Philosophy and theology were his principal subjects at Louvain, and he retained a concern with these matters throughout his life. Soon after his graduation he became concerned with mathematics and astronomy, studied these subjects informally under the guidance of Gemma Frisius, and acquired considerable skills as an engraver. His first known work was a globe, made in 1536; the following sear he published his first map—of Palestine. Mercator was a man of many talents, well versed in mathematics, astronomy, geography, and theology, and was also a great artist whose contributions to calligraphy and engraving influenced several generations of artisans. His lasting fame rests on his contributions to mapmaking: he was undoubtedly the most influential of cartographers.

Mercator’s maps cover a variety of subjects. During his sojourn at Louvain (1530–1552), besides his map of Palestine, he made maps of the world, globes, and scientific instruments and also established a reputation as a surveyor. Accused of heresy in 1544, and imprisoned for several months, he was released for lack of evidence, and in 1552 moved to Duisburg, where he became cosmographer to the duke of Cleves. His years at Duisburg were most fruitful: he published the first modern maps of Europe and of Britain, prepared an excellent edition of Ptolemy, and in 1569 published a world map on a new projection that still bears his name.

The 1569 world map of Mercatsor was designed for seamen. In order to lay out his course easily, the navigator needed a map where a line of constant bearing would cross all meridians at the same angle. Mercator designed a cylindrical projection, tangent at the equator; on it meridians and parallels are straight lines, intersecting at right angles, and distortion gradually increases toward the poles. Such a map shows loxodromes as straight lines, and for small areas it conforms to shapes, but lends to distort large areas, especially at high latitudes. Nonetheless, the Mercator projection, as modified at the end of the sixteenth century by Wright and Molyneux, remains the most important tool of the navigator.

Mercator’s second great contribution to geography and cartography was the collection of maps he designed, engraved, and published during the last years of his life. It consisted of detailed and remarkably accurate maps of western and southern Europe. In 1595, the year after Mercator’s death, his son, Rumold, published the entire collection under the title “Atlas— or Cosmographic Meditations on the Structure of the World,” the first time the word “atlas” was used to designate a collection of maps.


The most detailed and authoritative biography of Mercator is the work of H. Averdunk and J. Müller-Reinhard, Gerhard Mercator and die Geographen unter seinen Nachkommen, which is Petermanns Mitteilungen, Ergänzungsheft, no. 182 (1914). His correspondence was published by M. Van Durme, Correspondance Mercatorienne (Anvers, 1859). Among the main studies dealing with Mercator’s life and works, a special publication, on the occasion of the 450th anniversary of his birth, is “Gerhard Mercator— 1512–1594: zum 450. Geburtstag,” in Duisburger Forschungen, 6 (1962).

George Kish

Mercator, Gerardus

views updated May 18 2018

Mercator, Gerardus (1512–94) Flemish cartographer. His huge world map of 1569 employed the system of projection now named after him, in which lines of longitude, as well as latitude, appear as straight, parallel lines.

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