Geographic database of the Ile-de-France conurbation

Consultation and cooperation between public authorities in the Ile-de-France region, and particularly in the central conurbation, is hampered by the unavailability of the most essential elements of large-scale land mapping or, when they do exist, usually in an imperfect form, by the difficulty of sharing them (licenses, rights of use). This situation is just as worrying in the field of regulatory urban planning as it is in that of operational land use planning. Setting up shared cartography has therefore become a project in its own right, and a very useful one in many respects. The study consisted in drawing up an inventory of available geographic data from 10 communes (the City of Paris and 9 neighboring communes, 3 from each département), and then testing the feasibility of creating a modern reference geographic database (in GIS mode) by integrating the data from each. The inventory shows that everyone's needs are similar, but that the data collected by each is very heterogeneous. Where it has been possible to assemble similar data in raw form, this has only been done in degraded mode, and at best only covers 60 or 70% of the communes. For the 124 communes in the inner suburbs, this approach seems virtually impossible. On this basis, the creation and maintenance of a GIS would undoubtedly be impossible. The study therefore suggests the need to set up a genuine project for the creation and dissemination of geographical reference data, in collaboration with the départements, the region and the State's decentralized services, with the communes, their groupings and associated organizations also being the users.