Regional Historical Paper — 1:50,000 (Digital) — 1999 edition

Cartographic series taken from Austrian topographical production (scale 1:86.400) and Piedmontese (scale 1:50,000) of the first half of the nineteenth century.This is a primary knowledge base in the completeness of contents for a reading of the Italian pre-unitary territory.In the context of this editorial initiative, from this historical documentation available for almost all northern and central Italy, they were recomposed, on the 1:50,000 scale and with the cutting of the modern sheets of the Military Geographical Institute, the data relating to the area of Emilia-Romagna.The photographic images of the original sheets were scanned at 1016 dpi (points per inch), recognised about 15 trigonometric points for each sheet, similar transformations of the images constrained on the analytical coordinates of the known points have been performed; the new georeferencing presented metric residues with very low values; this also confirms the excellent quality of historical maps.