7.1 The Poisson process and spatial randomness 150
7.2 Inhibition models 156
7.3 Clustered models 158
8 Isotropy for spatial point patterns 167
8.1 Some large sample results 169
8.2 A test for isotropy 170
8.3 Practical issues 171
8.4 Numerical results 173
8.4.1 Poisson cluster processes 173
8.4.2 Simple inhibition processes 176
8.5 An application to leukemia data 177
9 Multivariate spatial and spatio-temporal models 181
9.1 Cokriging 183
9.2 An alternative to cokriging 186
9.2.1 Statistical model 187
9.2.2 Model fitting 188
9.2.3 Prediction 191
9.2.4 Validation 192
9.3 Multivariate covariance functions 194
9.3.1 Variogram function or covariance function? 195
9.3.2 Intrinsic correlation, separable models 196
9.3.3 Coregionalization and kernel convolution models 197
9.4 Testing and assessing intrinsic correlation 198
9.4.1 Testing procedures for intrinsic correlation and symmetry 201
9.4.2 Determining the order of a linear model of coregionalization 202
9.4.3 Covariance estimation 204
9.5 Numerical experiments 205
9.5.1 Symmetry 205
9.5.2 Intrinsic correlation 207
9.5.3 Linear model of coregionalization 209
9.6 A data application to pollutants 209
9.7 Discussion 213
10 Resampling for correlated observations 215
10.1 Independent observations 218
10.1.1 U-statistics 218
10.1.2 The jackknife 220
10.1.3 The bootstrap 221
10.2 Other data structures 224
10.3 Model-based bootstrap 225
10.3.1 Regression 225
10.3.2 Time series: autoregressive models 227
10.4 Model-free resampling methods 228
10.4.1 Resampling for stationary dependent observations 230
10.4.2 Block bootstrap 232
10.4.3 Block jackknife 233
10.4.4 A numerical experiment 233
10.5 Spatial resampling 236
10.5.1 Model-based resampling 237
10.5.2 Monte Carlo maximum likelihood 238
10.6 Model-free spatial resampling 240
10.6.1 A spatial numerical experiment 244
10.6.2 Spatial bootstrap 246
10.7 Unequally spaced observations 246
Bibliography 251
Index 263
In the spatial or spatio-temporal context, specifying the correct covariance function is fundamental to obtain efficient predictions, and to understand the underlying physical process of interest. This book focuses on covariance and variogram functions, their role in prediction, and appropriate choice of these functions in applications. Both recent and more established methods are illustrated to assess many common assumptions on these functions, such as, isotropy, separability, symmetry, and intrinsic correlation. After an extensive introduction to spatial methodology, the book details the effects of common covariance assumptions and addresses methods to assess the appropriateness of such assumptions for various data structures.
About the Author Michael Sherman, Professor of Statistics, Texas A&M University Michael Sherman has done extensive research on re-sampling methods for temporally or spatially dependent data and spatial statistics. He has published various papers in JASA, Biometrics and JRSS-B. In 2000 he created a course in Spatial Statistics at Texas A&M University and has given over 35 invited presentations at University seminars, ASA meetings and special topic meetings.
9780470699584 (cloth) 0470699582 (cloth)
2010029551
Spatial analysis (Statistics) Analysis of covariance.