Searching geographic resources through metadata-based queries for expert user communities

Many systems have been implemented to allow users to benefit from available data on the Internet. In this paper we present a retrieval method which takes into account specific properties of geographic data and discriminates among them on the basis of a core set of metadata elements. Along this line, four different typologies of queries have been proposed, which combine two levels of data searching with two kinds of matching. The query language and the data management are accomplished by following an XML approach based on XML.