Art. 3 -  by Miguel Ángel Latre Abadía - UNIZAR (Spain) 

Zaragoza Historical Maps (HistMapsZGZ) is the application that UNIZAR will develop for ENERGIC OD work package 6 on the development of new innovative applications and it will be developed for the Council of Zaragoza. UNIZAR and the Council of Zaragoza have a very intensive technological collaboration background since UNIZAR build IDEZAR, the SDI of the Council of Zaragoza, a pioneering infrastructure in the scope of the local administration in 2004. The HistMapsZGZ application development is included in this collaboration framework.

Currently, the Open Data Platform of the Zaragoza Council is offering a set of historical maps that range from 1879 to 1986, with the intention of increasing the number of these maps that are accessible through the platform. However, the format in which these maps are offered limits their reuse and exploitation: The original paper maps were scanned and are currently offered as open data through the platform as raster files in DjVu format. This is an open file format designed primarily to store scanned documents, very suitable for archiving and long term preservation of digitalised documents. Unfortunately, this format is not widespread, which is a barrier for their exploitation by software developers, the OD community and the citizens in general. Additionally, the DjVu format does not allow for its contents (maps), to be georeferenced.



















The council aims at offering them in a format that encourages their reuse and at providing tools to ease their access. The first step will consist in using a more common format and in georeferencing them. The second, in the development of the HistMapsZGZ application, which will provide a visualisation tool to portray this historical cartography. The application will retrieve the set of the offered historical maps from the Zaragoza Open Data Platform, and will offer users the possibility of exploring the maps with the usual tools (zooming, panning) and of navigating through time changing from one historical map to another. The tool will also allow comparing the historical maps to the current cartography of the city, according to the official, current maps provided by the Zaragoza SDI.

HistMapsZGZ will make use of the Spanish Virtual Hub that will be set up by work package 5 on the architecture and implementation of Virtual Hubs. The application will try to exploit the capabilities of the Virtual Hubs to the limit by, for instance, accessing the VH as a Web Map Tile Service and letting the VH to perform the access to the raw raster files and manage all the cache operations. UNIZAR expects that the VH will decrease the app development and maintenance effort.

HistMapsZGZ will contribute to the valorisation of cartographic heritage for the professional geomatic and historian community; for urban planners; for general citizens, by raising awareness about the changes and development of Zaragoza from 1879 to the present; and for tourists that will be provided with a more complete picture of the area they are visiting. HistMapsZGZ could be used for assessing Zaragoza urban development and transformation through the years and for future urban development planning. It can be used too as an ancillary tool for the archaeological prospects that precede any urban action.

HistMapsZGZ will open the possibility of allowing the inclusion of other volunteered historical maps of Zaragoza into the OD platform and into the app. The app will also serve as the basis for the georeferencing of the historic photographs archive of the Zaragoza Council. A large amount of historic photographs, digitalised but ungeoreferenced are currently offered as OD, but the Council itself has difficulty in georeferencing them, and the VGI community could be of help in this case. Also additional historic photographs could be volunteered.