ABSTRACT Handling Semantic Heterogeneities Using Declarative Agreements

The focus of this paper is on interoperability issues to achieve data integration in distributed databases for geographic applications. Our concrete application is in the context of the State of Wisconsin Land Information System (WLIS). In WLIS, data is stored in XML using independently maintained local databases. However, answers to many queries must span several databases. Our approach is based on the existence of a central ontology and on declarative transformations, called agreements, between the schemas of the local databases and the central ontology. Using our approach, end users can seamlessly query and aggregate semantically related data that is available throughout the state using a visual interface. An expert at the site of the local database uses another visual interface to specify the agreement between that database and the ontology. Our approach has been fully developed and tested

XML Database Integration for Visualizing US Election Results

In order for data from XML heterogeneous data sets to be viewed and analyzed using a common application, we propose the mapping between each schema and a central schema. The demo uses the example of an application to visualize the US Presidential election results, to illustrate our approach. To minimize the need for human intervention and code maintenance, a declarative approach is used. XML documents are treated as graphs and the queries posed by the user are converted to XPath expressions. The results of the XPath expression are collected and displayed to the user, using interactive maps in a web browser.