One of the world's foremost figures in cartography, Gerardus Mercator developed a new projection for the map of the world in 1569 that still bears his name. Before Mercator's time, world maps were basically useless to navigators plotting voyages of discovery and trade. The maps may have shown landmasses correctly, but generally they did not show proportional distance and direction so navigators could not plot a compass course. In his map, Mercator drew straight, equidistant longitude lines, perpendicular to latitude lines, forming agrid which could be used to accurately determine sea routes. Mercator createdand published numerous other maps, many of which were posthumously publishedby his son as Atlas' or Cosmographic Meditations on the Structure ofthe World. This marked the first use of the world atlas in connectionwith a book of maps. Mercator also introduced the use of italics to the textof maps.
Mercator was born Gerhard Kremer on March 5, 1512, in Rupelmonde, Flanders, and changed his name when he became a student at the University of Louvain in1530. Though Mercator studied philosophy and theology, he also developed an interest in astronomy, mathematics, geography, art and engraving. He studied the first two subjects under Gemmy Phrysius, a cartographer and mathematician.While Mercator lived in Louvain, from 1530 until 1552, Mercator made scientific instruments and worked as a surveyor, while makings his first maps and globes. His earliest globe was finished about 1536, and he published his firstmap in 1537. Its subject was Palestine. In 1844, Mercator was imprisoned forseveral months in Louvain for heresy, though he was set free due to lack of evidence. In 1552, Mercator moved to Duisberg in what is now Germany, where hewas employed by the Duke of Cleves. Mercator did his most significant work under Cleves's patronage in Duisberg.
In 1569, Mercator designed his Great World Map to facilitate sea travel, inspired by his contact with sea captains and navigators. His grid based of equidistant meridians (longitude lines) and parallels (latitude lines) drawn perpendicularly is known as a graticule. Mercator's graticule allowed constant compass bearing to be plotted as a straight line. While Mercator's map was useful for navigators because it preserved constant compass directions, it had drawbacks. Landmasses were not depicted in their true area and proportions, except at the equator. The further from the equator the landmass is, the bigger it looks on Mercator's map. Hence, Greenland looks much larger than the continent of South America, though it is really half its size. The North and SouthPoles cannot be projected at all. But the relationships between these landmasses are correctly depicted. Mercator's innovation did not become widespread until 1599, when Edward Wright published corrective tables for navigator's use.
Mercator also designed, engraved, and published many maps of Europe and its different parts. In 1554, for example, he published an accurate, detailed mapof Europe. Eventually, 107 of these maps appeared in the atlas published by his son in 1595. Mercator also built globes on commission, including a one made of crystal and wood for the Holy Roman Emperor, Charles V. Mercator died inDuisberg on December 2, 1594.