Famous charts and forgotten fragments: exploring correlations in early Portuguese nautical cartography

Abstract

The authors of the well-known collection Portugaliae Monumenta Cartographica hinted at connections between two anonymous portolan charts from the beginning of the sixteenth century, namely the portolan chart at the Bibliothèque Municipale of Dijon and a fragment of a chart kept in Lisbon in the Archive at Torre do Tombo. Later, they also mentioned affinities between those two charts and the famous chart known as Kunstmann III. However, they did not pursue these observations further. The present paper proceeds from where those researchers stopped investigating and proposes a fresh look on this cartographic material by combining a traditional historical approach with modern digital techniques. First, a comparative study of the toponomy of a common area of the charts will be presented. Later, each chart will be examined with the help of cartometric methods to access their implicit geometry. The advancements on the study of correlations between these charts will be shown, thus confirming that the combination of traditional and digital methods of investigation open very promising perspectives to the study of unsolved questions in the History of Cartography.