Photogrammetric techniques and surveying applied to historical map analysis

Since historical maps are kept in digital format archives, they have not only the planimetric errors attributable to the cartographer but also those transferred during digitalising. This paper describes a methodology based on photogrammetric techniques and surveying applied to evaluate the accuracy of historical maps. The aim of the study is to take reference points on tracing paper from the original map and ground control points in order to use photogrammetric techniques to recover the metrics of the digitalised map. This ensures that the historical map in digital form has the same metric quality as the original map, since the errors arising from scanning are removed. This method is applied to 1775 map of the Real Sitio de Aranjuez (Spain), demonstrating that the application of photogrammetric techniques are useful tools for correction and analysis of historical maps. Consequently, photogrammetric techniques applied to the analysis of historical maps open up new perspectives for the study of the historical Cartography.