Redundancy Reduction for Prevalent Co-Location Patterns

Spatial co-location pattern mining is an interesting and important task in spatial data mining which discovers the subsets of spatial features frequently observed together in nearby geographic space. However, the traditional framework of mining prevalent co-location patterns produces numerous redundant co-location patterns, which makes it hard for users to understand or apply. To address this issue, in this paper, we study the problem of reducing redundancy in a collection of prevalent co-location patterns by utilizing the spatial distribution information of co-location instances. We first introduce the concept of <italic>semantic distance</italic> between a co-location pattern and its super-patterns, and then define redundant co-locations by introducing the concept of <italic> δ-covered</italic>, where <inline-formula><tex-math notation="LaTeX">$\delta \,(0\leq \delta \leq 1)$</tex-math> <alternatives><inline-graphic xlink:href="wang-ieq1-2759110.gif"/></alternatives></inline-formula> is a coverage measure. We develop two algorithms <italic>RRclosed</italic> and <italic>RRnull</italic> to perform the redundancy reduction for prevalent co-location patterns. The former adopts the <italic>post-mining</italic> framework that is commonly used by existing redundancy reduction techniques, while the latter employs the <italic>mine-and-reduce </italic> framework that pushes redundancy reduction into the co-location mining process. Our performance studies on the synthetic and real-world data sets demonstrate that our method effectively reduces the size of the original collection of closed co-location patterns by about 50 percent. Furthermore, the RRnull method runs much faster than the related closed co-location pattern mining algorithm.