A comprehensive framework for exploratory spatial data analysis:Moran location and variance scatterplots  

作　　者：J.G.Negreiros M.T.Painho F.J.Aguilar M.A.Aguilar 

机构地区：[1]Institute of Statistics and Information Management,New University of Lisbon,Campus de Campolide,Lisbon 1070-312,Portugal [2]Department of Agricultural Engineering,Almerı´a University,Almeria 04120,Spain

出　　处：《International Journal of Digital Earth》2010年第2期157-186,共30页国际数字地球学报（英文）

摘　　要：A significant Geographic Information Science(GIS)issue is closely related to spatial autocorrelation,a burning question in the phase of information extraction from the statistical analysis of georeferenced data.At present,spatial autocorrelation presents two types of measures:continuous and discrete.Is it possible to use Moran’s I and the Moran scatterplot with continuous data?Is it possible to use the same methodology with discrete data?A particular and cumbersome problem is the choice of the spatial-neighborhood matrix(W)for points data.This paper addresses these issues by introducing the concept of covariogram contiguity,where each weight is based on the variogram model for that particular dataset:(1)the variogram,whose range equals the distance with the highest Moran I value,defines the weights for points separated by less than the estimated range and(2)weights equal zero for points widely separated from the variogram range considered.After the W matrix is computed,the Moran location scatterplot is created in an iterative process.In accordance with various lag distances,Moran’s I is presented as a good search factor for the optimal neighborhood area.Uncertainty/transition regions are also emphasized.At the same time,a new Exploratory Spatial Data Analysis(ESDA)tool is developed,the Moran variance scatterplot,since the conventional Moran scatterplot is not sensitive to neighbor variance.This computer-mapping framework allows the study of spatial patterns,outliers,changeover areas,and trends in an ESDA process.All these tools were implemented in a free web e-Learning program for quantitative geographers called SAKWeb#(or,in the near future,myGeooffice.org).

关 键 词：GEOCOMPUTATION exploratory spatial data analysis spatial autocorrelation Moran scatterplot Moran’s I variography 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]