Gerardus Mercator (1512-1594), Latin name of Gerhard Kremer, was a Flemish cartographer, geographer and mathematician best known for his mapping work, especially the Mercator projection, which used straight lines to indicate latitude and longitude. He was born in Rupelmonde.
In 1537 he produced his first map. Mercator studied in Leuven, Belgium, under Gemma Frisius, and in 1552 he became a mapmaker and lecturer at the University of Dvisburg. His map of Europe (published in 1554) was the best of its kind for many decades. He produced a map of the British Isles in 1564 and in the same year was made court cosmographer to Duke William of Cleve.
In 1568 he devised and produced a system of map projection, now called Mercator projection. This system represents meridians by parallel lines and parallels of latitude by straight lines intersecting the meridians at right angles. Only four copies of this map are known to exist. Mercator's great Atlas (begun in 1569), in which he sought to describe the creation and history of the world, was printed in its unfinished state by his son in 1595.