The Mapping of Africa on the Nautical Charts of the Age of Discovery

The shape of Africa on Iberian nautical charts of the late-fifteenth and early-sixteenth century is surprisingly mature. The portrayal of the outline of Africa on the Cantino planisphere of 1502 is so good that it was not surpassed in the next two, possibly three centuries. The African coastline on the Cantino planisphere is a mosaic of accurate regional charts on the plate-carrée projection, each with its own scale and orientation. The same holds for its Iberian predecessors. The shape of the parts of Africa depicted on these regional charts was essentially correct on the oldest chart (c. 1471) and was copied to later charts. The projective properties of the regional charts are incompatible with the navigation and charting techniques used in that period. Therefore, serious doubt is cast on the established view that Portuguese pilots and cartographers were the original creators of the source charts.