Search algorithms for multiway spatial joins

Author： Papadias Dimitris Arkoumanis Dinos

ISSN： 1365-8824

Source： International Journal of Geographical Information Science, Vol.16, Iss.7, 2002-11, pp. : 613-639

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Abstract

This paper deals with multiway spatial joins when (i) there is limited time for query processing and the goal is to retrieve the best possible solutions within this limit (ii) there is unlimited time and the goal is to retrieve a single exact solution, if such a solution exists, or the best approximate one otherwise. The first case is motivated by the high cost of join processing in real-time systems involving large amounts of multimedia data, while the second one is motivated by applications that require 'negative' examples. We propose several search algorithms for query processing under theses conditions. For the limited-time case we develop some non-deterministic search heuristics that can quickly retrieve good solutions. However, these heuristics are not guaranteed to find the best solutions, even without a time limit. Therefore, for the unlimited-time case we describe systematic search algorithms tailored specifically for the efficient retrieval of a single solution. Both types of algorithms are integrated with R-trees in order to prune the search space. Our proposal is evaluated with extensive experimental comparison.