Mapping Sardinia in the 19th Century. The “Piano della rada e darsena di Cagliari”

The essay is part of a wider research that analyzes the cartographic heritage of Sardinia between the end of the eighteenth century and the first half of the nineteenth century. This period -characterized by a significant development of the survey methodologies and by an improvement of the topographical instrumentsdetermines an excellent quality of maps in terms of the precision of the territorial data and graphic representation. Sardinia’s territory in this era is interested by an intense knowledge activityespecially of the coastal landscape- carried out by French and English Navy’s experts and by the Piedmontese officers. Coastal defense -entrusted to the strongholds of Cagliari, Alghero and Castelsardo and to a system of watchtowers- and access to ports, are the main reasons that guide the reconnaissance. The extensive documentation kept in the Archives clearly shows the methodologies employed based on the use of cornerstones (as towers, bell towers, or others elements visible even at a great distance) necessary for the construction of an accurate survey grid, that allow -if compared with aerial photogrammetric surveys- an historical reinterpretation of landscape transformations. Among these documents the “Piano della rada e darsena di Cagliari”, realized by the French Navy in 1841 and analyzed in the present contribution, arouses considerable interest.