作者机构:[1]Agricultural College, JiangxiAgricultural University, Nanehang 330045, China, [2]China Earthquake Networks Center, Beij'ing 100036, China, [3]Department of Precision Instrument andMechanology, Tsingkua University, Beijing 100084, China
相关基金:Acknowledgements This paper is supported by the Key Project of Chinese National Programs for Fundamental Research and Development (973 program) (2008CB425704). We thank Dr. Tom Minka (the Mit Media Laboratory, USA) and Prof. Peter Diggle (the Medicine Department of Lancaster University, UK) for their extremely valuable help during the preparation of this paper, and we are also grateful to Prof. Bailian Li (the Ecological Complexity and Modeling Lab. of California University, Riverside, USA) for providing us with the necessary literatures. R, Map, Mapproj and Splancs are all freely available from the R website (URL http://www.cran.r-project.org).