Discovering Regional Co-location Patterns for Sets of Continuous Variables in Spatial Datasets

This paper proposes a novel framework for mining regional co-location patterns with respect to sets of continuous variables in spatial datasets. The goal is to identify regions in which multiple continuous variables with values from the wings of their statistical distribution are co-located. A co-location mining framework is introduced that operates in the continuous domain without and which views regional co-location mining as a clustering problem in which an externally given fitness function has to be maximized. Interestingness of co-location patterns is assessed using products of z-scores of the relevant continuous variables. The proposed framework is evaluated by a domain expert in a case study that analyzes Arsenic contamination in Texas water wells centering on regional co-location patterns. Our approach is able to identify known and unknown regional co-location patterns, and different sets of algorithm parameters lead to the characterization of Arsenic distribution at different scales. Moreover, inconsistent co-location sets are found for regions in South Texas and West Texas that can be clearly attributed to geological differences in the two regions, emphasizing the need for regional co-location mining techniques. Moreover, a novel, prototype-based region discovery algorithm named CLEVER is introduced that uses randomized hill climbing, and searches a variable number of clusters and larger neighborhood sizes. 1 Author is with the Lunar and Planetary Institute, Houston, TX 77058 2 Author is with Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712 Finding Regional Co-location Patterns for Sets of Continuous Variables in Spatial Datasets Christoph F. Eick, Rachana Parmar, Wei Ding Department of Computer Science University of Houston Houston, TX 77204-3010 Tomasz F. Stepinski Lunar and Planetary Institute Houston, TX 77058 Jean-Philippe Nicot* Bureau of Economic Geology, Jackson School of Geosciences University of Texas at Austin Austin, TX 78712