Using XML for the exchange of updating information between geographical information systems
The growth of institutional investment in Geographic Information Systems (GISs) testifies to their increasing importance as analytical decision-making tools utilising highly specialised data. However, a simple system still does not exist for the easy and consistent integration of evolutions into GIS. At present institutions either retrieve the updates themselves, often failing entirely results in information loss and major inconsistencies or they purchase reference data sets from geographic information producers. The problems and expense associated with the integration of updates for geographic databases are well documented. However, it is the lack of choice available in the method of delivering these updates that results in inefficiency, as a whole new database is often delivered even when there is relatively little real change in its data. This paper details the implementation of a new solution for the exchange of updating information for geographical information systems. Developed at the COGIT laboratory of IGN (the French National Mapping Agency) it is based on XML (eXtensible Markup Language) and aims to providing users with structured and detailed information concerning evolutions in order to make their integration into systems easier and more consistent. We highlight the challenges and benefits involved in implementing this transfer method, such as the interoperability between GIS software and the problems of real time updating of databases within client/server architectures. This paper aims to demonstrate that the use of XML in data exchanges is likely to become commonplace between GISs, especially with the aid of Java technology and the web-based client/server data access. It may even be possible to supply consumers with adapted updates on demand and enable real time maintenance of databases to be carried out.
xml (extensible markup language) graphical information systems metadata database evolution geometric modification html sfxml (simple feature xml) sgml (standard generalised markup language) gml (geography markup language) sotf (spatial object transfer format) dtd (document type definition)