# [R-sig-Geo] anisotropy modeling

Edzer Pebesma edzer.pebesma at uni-muenster.de
Wed Jul 13 10:09:58 CEST 2011

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On 07/12/2011 10:52 PM, Matevž Pavlič wrote:
> Hi all,
>
>
>
> i 'm am not entirely sure I understand anisotropy kriging in R.
>
> I have a data set in which is (at least i think so) anisotropy is clearly visible. So I made directional variograms....
>
> So as i understand, the only thing that is different from >normal< kriging is the  >anis< property in which you define the diffrenece of ranges? Is that coreect?

it assumes the variogram to fit to is in the major (correlation)
direction (or averaged over all directions).

>
> Bellow is the code i use :
>
>
>
> a<-5000/7000
>
> print(plot(variogram(Z ~ 1, DF, map = TRUE, cutoff = 15000, width = 100), main = "Variogram map, podlaga",col.regions = terrain.colors(64)))
>
> v1.a<-variogram(Z~1, DF, alpha=c(45, 135))
>
> (vmf.a <- fit.variogram(v1.a, vgm(2900, "Pen", 5500, 300, anis = c(135, a))))
>
> print(plot(v1.a, pl = F, pch = 20, col = "blue"))
>
> print(plot(v1.a, plot.numbers = F, pch = 20, col = "darkblue", model = vmf.a))
>
>
>
> podlaga.aniso<-krige(Z~1, DF[-zerodist(DF)[,1],], grd, vmf.a )
>
> print(spplot(podlaga.aniso, zcol="var1.pred", col.regions=terrain.colors(64), contour=T, pretty=T, cuts=15, key.space="right"))
>
> print(spplot(podlaga.aniso,  zcol="var1.var", col.regions=terrain.colors(64), contour=T, pretty=T, cuts=15, key.space="right"))
>
> writeGDAL(podlaga.aniso, "podlaga_aniso.tif")
>
>
>
> thanks for info,
>
>
>
> m
>
>
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>
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--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de

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