Journal of Geo-information Science >
A Fast Method for Making Candidate Clusters in Spatial Scan Statistic Method
Received date: 2013-01-14
Revised date: 2013-03-20
Online published: 2013-08-08
Spatial scan statistic method is a widely adopted spatial cluster detection method in the field of public health surveillance. It can detect a sub-zone where the number of disease cases rises abnormally, based on infectious disease surveillance data, and thus is able to make early warning on possible outbreak of infectious disease. Chinese Center for Disease Control and Prevention (China CDC) launched China Infectious Disease Automated-alert and Response System (CIDARS) in 2004, which handles the infectious disease surveillance data of all of the counties of China to detect possible case clusters. The making of candidate clusters is a key step to this method, which to some extent determines the accuracy and time efficiency of the spatial scan statistic method. There are two deficiencies if the existing candidate clusters making method is applied to a very big research area with a lot of sub-regions. The first is that, the inappropriate separation distance of grid points might miss a lot of possible candidate clusters, which affects the accuracy of detected result. The second is that, the existing method might duplicate a great number of candidate clusters, which could prolong the computing time of subsequent spatial scan operation. In this paper a new efficient method is proposed according to the former existing candidate clusters making method. Based on the correct setting to the separation distance of grid points, the new method could greatly reduce the possibility of missing of some possible candidate clusters. At the same time, applying multiple-sort arithmetic, the proposed new method could find and delete a great number of duplicate clusters in the original-making candidate clusters in a shorter time. Finally, the paper applies and tests the proposed method for the making of candidate clusters in 608 counties in southwest Shandong Province and proves that the method works satisfactorily in both two aims, that is, it reduced the computing time and reduced the missing of candidate clusters.
Key words： candidate cluster; grid; multiple-sort; spatial scan statistic
LI Xiao-Zhou, WANG Jin-Feng . A Fast Method for Making Candidate Clusters in Spatial Scan Statistic Method[J]. Journal of Geo-information Science, 2013 , 15(4) : 505 -511 . DOI: 10.3724/SP.J.1047.2013.00505
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