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Optimizing Multi-Way Spatial Joins of Web Feature Services


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1

College of Geomatics and Geoinformation, Guilin University of Technology, Guilin 541004, China

2

Guangxi Key Laboratory of Spatial Information and Geomatics, Guilin 541004, China





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Academic Editors: Zhao-Liang Li and Wolfgang Kainz

Abstract Web Feature Service WFS is a widely used spatial web service standard issued by the Open Geospatial Consortium OGC. In a heterogeneous GIS application, a user can issue a query that relates two or more spatial datasets at different WFS servers. Multi-way spatial joins of WFSs are very expensive in terms of computation and transmission because of the time-consuming interactions between the servers and the client. In this paper, we examine the problems of multi-way spatial joins of WFSs, and we present a client-side optimization approach to generate good execution plans for such queries. The spatial semi-join and area partitioning-based methods are combined to prune away non-candidate objects in processing binary spatial joins, and the filtering rate is used as an index to determine the execution strategy for each sub-area. Two partitioning methods were tested, and the experimental results showed that both are effective if a proper threshold to stop the partitioning is chosen. In processing multi-way spatial joins of WFSs, the filtering rate is used as an indicator to determine the ordering of the binary joins. The optimization method is obviously superior to the other two methods when there are adequate spatial objects involved in the join query, or when more datasets are involved in the join query. View Full-Text

Keywords: multi-way spatial join; Web Feature Services; execution plan; client-side; optimization multi-way spatial join; Web Feature Services; execution plan; client-side; optimization





Author: Guiwen Lan 1,2, Qiang Zhang 1,* , Zhao Yang 1 and Tong Li 1

Source: http://mdpi.com/



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