The sudden appearance of portolan charts, realistic nautical charts of the Mediterranean and Black Sea, at the end of the thirteenth century is one of the most significant occurrences in the history of cartography. Using geodetic and statistical analysis techniques these charts are shown to be mosaics of partial charts that are considerably more accurate than has been assumed. Their accuracy exceeds medieval mapping capabilities. These sub-charts show a remarkably good agreement with the Mercator map projection. It is demonstrated that this map projection can only have been an intentional feature of the charts’ construction. Through geodetic analysis the author eliminates the possibility that the charts are original products of a medieval Mediterranean nautical culture, which until now they have been widely believed to be.

This book from the Peter Whitfield cartographic series traces the history of humankind's relation to the sea as revealed in ten centuries of maritime maps. Presenting sixty maps reproduced in color over double-page spreads, and commentary describing their special features and their significance in the history of navigation, the book explores ancient navigation; the Middle Ages and the Age of Discovery; the printed sea chart, 1600-1800; and the modern sea chart.

Professor Harvey traces the development of western mapmaking from the early Middle Ages to the first printed maps of the late 15th century, discussing their traditions, artistic and technical aspects, and uses.