XML-based information mediation with MIX
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Capabilities-based query rewriting in mediator systems
DIS '96 Proceedings of the fourth international conference on on Parallel and distributed information systems
The Geometry of Uncertainty in Moving Objects Databases
EDBT '02 Proceedings of the 8th International Conference on Extending Database Technology: Advances in Database Technology
Integrating GIS and Imagery Through XML-Based Information Mediation
ISD '99 Selected Papers from the International Workshop on Integrated Spatial Databases, Digital Inages and GIS
Supporting Imprecision in Multidimensional Databases Using Granularities
SSDBM '99 Proceedings of the 11th International Conference on Scientific and Statistical Database Management
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Web-based federated spatial databases usually do not support accuracy-aware query processing despite growing availability of individual data quality descriptions. This paper introduces a mechanism for making data quality information operational through the process of accuracy-based query rewriting. A number of keywords are added to SQL to express accuracy constraints in a spatial query. Depending on the specification of error in underlying data sets, a query containing accuracy constraints is rewritten as a single or a set of crisp spatial queries, i.e. those that do not require further accuracy-based disambiguation. The rewriting uses binding of GIS spatial operations to error models via a collection of error propagation templates. This mechanism is implemented as a Web service that works in conjunction with a spatial mediator to aid in rewriting spatial queries in the presence of accuracy metadata.