Gerardus Mercator (1512-1594) was a 16th Century Flemish cartographer whose most important innovation was his 1569 map, on 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 accurately depicted the shapes and directions of landmasses, which made the map very useful for sailors before the invention of complex navigation systems.
This type of map, which became known as the Mercator Projection, enabled sailors to precisely plot a course from one place to another. He also introduced the term atlas for a collection of maps.
Mercator's map was a significant advance in cartography, allowing explorers, adventurers and merchants an effective means to more easily navigate unfamiliar waters and avoid treacherous conditions.