Lyon, written historical source GIS – method and examples of developments

Abstract

The Lyons historical GIS was developed from the end of the 1990s whit the goal to reach a new un­derstanding of the transformation of urban and social spaces by spatializing data at the buildings scale. We thought that by such a jump in precision of a factor 100, from a subdivision by 36 quarters to one by 3,500 buildings in the modern period, the mapping would lead to new perspectives and results in urban history. This involved working through two centuries of archival records, taxes registers, censuses, building permits, property changes in order to create critically researched data bases followed by vector GIS layers. It was necessary develop a method to reveal the implicit spatiality of these written sources, to establish a mapping topography, allowed by a careful and geometrically checked reconstruction of the city’s plot pattern together with its variation befo­re 1800, and to take into account the space trans­formation, studied at the actual scale of indivi­dual investments, owing to the building permits checked with the still extant constructions, and the administrative record.