Is the same true for autofitVariogram {automap} ? Shweta
On Wed, Jul 13, 2011 at 1:13 PM, Edzer Pebesma < edzer.pebe...@uni-muenster.de> wrote: > help(fit.variogram) has the following description: > > Fit ranges and/or sills from a simple or nested variogram model to > a sample variogram > > I suspected it would completely ignore anisotropy settings. However, > this seems not to be the case: > > > library(gstat) > Loading required package: sp > Loading required package: spacetime > Loading required package: zoo > Loading required package: xts > > loadMeuse() > > v0 = variogram(zinc~1,meuse, alpha = 0, tol.hor = 45) > > v90 = variogram(zinc~1,meuse, alpha = 90, tol.hor = 45) > > v = variogram(zinc~1,meuse) > > fit.variogram(v, vgm(1, "Exp", 300, anis=c(90,1))) > model psill range > 1 Exp 166238 323.6674 > > fit.variogram(v, vgm(1, "Exp", 300, anis=c(90,.1))) > model psill range ang1 anis1 > 1 Exp 166238 3236.674 90 0.1 > > fit.variogram(v0, vgm(1, "Exp", 300, anis=c(90,.1))) > model psill range ang1 anis1 > 1 Exp 146068.7 2772.751 90 0.1 > > fit.variogram(v90, vgm(1, "Exp", 300, anis=c(90,.1))) > model psill range ang1 anis1 > 1 Exp 200767.2 4027.282 90 0.1 > > > > > On 07/13/2011 11:34 AM, Matevž PavliÄ wrote: > > Hi, > > > > thanks for the reply. Can you explain this a little bit more : > > " it assumes the variogram to fit to is in the major (correlation) > direction (or averaged over all directions)." > > > > I don't know exactly ehat it means.... > > m > > > > -----Original Message----- > > From: r-sig-geo-boun...@r-project.org [mailto: > r-sig-geo-boun...@r-project.org] On Behalf Of Edzer Pebesma > > Sent: Wednesday, July 13, 2011 10:10 AM > > To: r-sig-geo@r-project.org > > Subject: Re: [R-sig-Geo] anisotropy modeling > > > > > > > > On 07/12/2011 10:52 PM, Matevž PavliÄ 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? > > > > Yes. Please note that fit.variogram ignores anything about anisotropy, 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 > >> > >> > >> [[alternative HTML version deleted]] > >> > >> _______________________________________________ > >> R-sig-Geo mailing list > >> R-sig-Geo@r-project.org > >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > > Edzer Pebesma > > Institute for Geoinformatics (ifgi), University of Münster Weseler StraÃe > 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 > http://ifgi.uni-muenster.de > > http://www.52north.org/geostatistics e.pebe...@wwu.de > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > -- > Edzer Pebesma > Institute for Geoinformatics (ifgi), University of Münster > Weseler StraÃe 253, 48151 Münster, Germany. Phone: +49 251 > 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de > http://www.52north.org/geostatistics e.pebe...@wwu.de > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > [[alternative HTML version deleted]]
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