A rede hidrográfica no mapa de Portugal de Fernando Álvaro Seco (1560)

Abstract

A cartographic examination of the hydrographic network demonstrates, on one hand, its high quality in general and allows us, on the other hand, to seek reasons for the mistakes in its drawing and orienting, as well as the omissions made. To this effect, the plotting of the rivers was compared with itineraries description of that same period. An examination was also made of the distribution of bridges and hydronymy. A solid spatial correlation was found to exist between the quality of the plotting and the density and frequency of the various itineraries, along with the influence of military concerns for the Eastern boundary of the Portuguese kingdom. The correlation with the regional properties of relief and climate is important but less direct. The map-maker undertook complex work of compilation and harmonisation of documents of several origins, probably dating much further back than to when the map was offered in Rome in 1560.