Message-ID: <3DAD9804.2E3DF6E2@ipimar.pt>
Date: 2002-10-16T16:47:00Z
From: Juan Zwolinski
Subject: Ordinary and simple kriging
I'm performing ordinary and simple kriging from a set of non-negative
values:
>krige.control.sk<-krige.control(type.krige="sk",obj.model=my.variogram.model,beta=my.variogram.model$beta)
>sk<-krige.conv(cadiz.geo,data=amostragem.cadiz$dia1.std,locations=as.matrix(cadiz.polygrid[,c(1,2)]),krige=krige.control.sk)
krige.conv: model with constant mean
krige.conv: Kriging performed using global neighbourhood
and
>krige.control.ok<-krige.control(type.krige="ok",obj.model=my.variogram.model)
>ok<-krige.conv(cadiz.geo,data=amostragem.cadiz$dia1.std,locations=as.matrix(cadiz.polygrid[,c(1,2)]),krige=krige.control.ok)
krige.conv: model with constant mean
krige.conv: Kriging performed using global neighbourhood
where my.variogram.model is gaussian fitted through variofit with
"cressie" weigths.
I'm getting the same predicted values for both models, 12% of them
being negative. Is it because simple and ordinary kriging predictions
are not including the overall mean? If this is the case what mean should
I use?
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