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Bayesian kriging Instead of estimating the parameters, we put a prior distribution on them, and update the distribution using the data. Model: Matrix with i,j-element C(s i -s j ; ) (correlation) measurement error T (Z(s 1 )...Z(s n )) T
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Prior and posterior Prior: Posterior: Predictive distribution: kriging predictor
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Specifically Exponential isotropic correlation function: Default correlation model in geoR. Prior on defaults to flat, but can also be normal or fixed Prior on 2 defaults to reciprocal, but can be scaled inverse chisquare or flat Prior on can be exponential, uniform, reciprocal, squared reciprocal, or user specified (discrete)
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More priors A prior is assigned to. Defaults to fixed=0, but can also be uniform or user specified (discrete). These choices are made for computational reasons. For example, the posterior distribution of 2 is inverse chisquared. For details, see http://www.leg.ufpr.br/geoR/geoRdoc/bayeskrige.pdf
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Prior/posterior of
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Variogram estimates mean median mode
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Predictive mean
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Comparison Ordinary kriging Bayesian kriging
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Kriging variances BayesClassical range (52,307) range (170,278)
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Introduction to geoR Commands available at the web site. “Official” introduction to geoR is http://www.leg.ufpr.br/geoR/geoRdoc/vignette/geoRint ro.pdf http://www.leg.ufpr.br/geoR/geoRdoc/vignette/geoRint ro.pdf
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