Acta Geodaetica et Cartographica Sinica ›› 2018, Vol. 47 ›› Issue (9): 1250-1260.doi: 10.11947/j.AGCS.2018.20170321

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A Nonparametric Test Method for Identifying Significant Cross-outliers in Spatial Point Dataset

YANG Xuexi, DENG Min, SHI Yan, TANG Jianbo, LIU Qiliang   

  1. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China
  • Received:2017-06-19 Revised:2018-05-10 Online:2018-09-20 Published:2018-09-26
  • Supported by:
    The National Natural Science Foundation of China (Nos. 41471385;41730105);The National Key Research and Development Program of China (No. 2016YFB0502303);The Fundamental Research Funds for the Central Universities of Central South University (No. 2016zzts085)

Abstract: In the field of geography,a spatial outlier is an object whose non-spatial attribute value is significantly different from the values of its spatial neighbors. Detection of spatial outliers will be helpful to uncover special geographical phenomenon,so it has become an important branch of spatial data mining.Although existing methods are able to measure spatial outlier factor,the significance of these outliers can not be evaluated in an objective way. Furthermore,the existing methods are mainly designed for single class dataset,without taking into account the interaction between different categories of dataset.In this study,a nonparametric test was developed to identify the significant cross-outliers in spatial point dataset.Firstly,a reasonable and stable spatial neighborhood is constructed for the primary dataset entitys using the constraint Delaunay triangulation.Then,using the number of reference dataset entitys falling in the spatial reference neighbor radius to measure the initial outlier factor.Constructed the support domain by α-Shape method,the null model is constructed based on spatial randomness process,and the significant spatial cross-outliers are identified by statistical test.Finally,the stability of the spatial cross-outlliers are evaluated by the living distance.Experimentson on both simulated and real-world datasets show that the proposed permutation test is effective for determining significant spatial cross-outliers in spatial point datasets.

Key words: spatial data mining, spatial outlier detection, cross-outlier, nonparametric test, significance

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