Enriching SQWRL Queries in Support of Geospatial Data Retrieval from Multiple and Complementary Sources

Finding relevant geospatial information is increasingly critical because of the growing volume of geospatial data available through distributed environments. It is also a challenge for the ongoing development of the Geospatial Semantic Web. Data brokers provide searchable repositories through which users can generally retrieve the requested data. But generally, these mechanisms lack the capacity to find and combine complementary data from multiple sources. However, such capacity is needed to answer complex queries. In this paper, we propose a new type of system that supports geospatial data retrieval from multiple and complementary sources. The system uses the Semantic Query-Enhanced Web Rule Language (SQWRL) to support reasoning with complex queries and to enable combination of complementary and heterogeneous data. We have developed and included in this system a query expansion method for the resolution of semantic heterogeneities. The proposed system is illustrated with a case study on the detection of hazardous events.