Web geoservices and ancient cadastral maps: the Web C.A.R.T.E. project

In the State Archive of Como, Northern Italy, about 15000 historical maps are preserved. These maps belong to different cadastral productions: the Theresian cadastre (1718-1722), the Lombardo-Veneto cadastre (1854-1858), the updates of 1898 and for some locations also the New Lands Cadastre maps (1905). These large-scale representations have not only a considerable aesthetic value but mostly a cultural and historical one, and this is why they are nowadays a precious instrument for historical scholars and professionals in the urban and territorial planning. The project Web C.A.R.T.E. (Web Catalogo e Archivio delle Rappresentazioni del Territorio e delle sue Evoluzioni), sponsored by the Fondazione Provinciale della Comunità Comasca Onlus and presented in the paper, has been started to enhance this immense cartographic heritage using the most recent technologies of map processing and web services.

 

In the Web C.A.R.T.E. framework the historical maps undergo a well structured series of phases. After the high-resolution digitization step, a georeferencing and warping procedure is needed to place them in the actual Italian reference system, thus making it possible to overlap them to the current cartography. Different georeferencing mathematical models of both proprietary and open source software have been tested, comparing their abilities to face the complex tasks of managing large raster maps and providing at the same time suitable interpolation models and performances of the results.

 

Dealing with historical georeferenced maps, it's also of the utmost importance their documentation in terms of metadata. Up to date in Italy exists a metadata schema that is proposed by CNIPA (Centro Nazionale per l’Informatica nella Pubblica Amministrazione), which implements ISO19115 and is in agreement with the INSPIRE European Directive. Metadata for the  georeferenced cadastral maps have therefore been compiled according to that standard using an ad hoc localized version of GeoNetwork Opensource. We aim to provide an official Italian version of the software which is not today included in the application standard distribution.

 

A dedicated webGIS client based again on FOSS solutions has finally been realized to make every possible user, also non-experts in GIS field, interact in a friendly way with maps of different epochs and compare them to the current cartography. The large dimension of raster maps, together with the need of providing an interactive and fast navigation of the webGIS, represented one of the biggest challenges of the project and led to specific choices both on the server and client side.