Leonardo da Vinci's World Map

In addition to his better known artistic, scientific and engineering talents, Leonardo da Vinci has an extensive reputation as a cartographer, drawing maps for a wide range of hydro-engineering projects for the rulers of Florence, Milan, Arezzo and the Vatican, amongst others. However, he is not generally acknowledged as authoring a world map (or mappamundi) spanning the globe, which was the domain of a few specialized cartographers of the era. Nevertheless, there is a world map among his papers in the Royal Library, Windsor, which is one of the very first to name the Americas, and has the correct overall configuration of the continents, including an ocean at the north pole and a continent at the south pole. Moreover, it has a unique cartographic projection onto eight spherical-geometry triangles that provide close to isometric projection throughout the globe. Although the authenticity of this world map has been questioned, there is an obscure page of his notebooks in the Codex Atlanticus containing a sketch of this precise form of global projection, tying him securely to its genesis. Moreover, the same notebook page contains sketches of eight other global projections known at that time (early C16th), from the Roman Ptolomaic conic section projection to Rossellli's [[i]] oval planispheric projection. This paper explores further remarkable aspects of the geometry and history of Da Vinci's unique mappamundi. References [i] Rosselli F (1508) In: Almagià R. (1951) On the cartographic work of Francesco Rosselli. Imago Mvndi. International Society for the History of Cartography 8: 27-34