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 a grid which could be used to accurately determine sea routes. Mercator created and published numerous other maps, many of which were posthumously published by his son as Atlas' or Cosmographic Meditations on the Structure of the World. This marked the first use of the world atlas in connection with a book of maps. Mercator also introduced the use of italics to the text of maps.

Mercator...