geoR interpolation with log transform
Dear Kapo I've replied your private message with some details Let me add the "honouring the points" will dependes on which interpretation is given to the nugget (micro-scale variation measurement error or a combination of these) In geoR there are arguments micro.scale and signal in n krige.control() and output.control() respectivelly, to control such behaviour Paulo Justiniano Ribeiro Jr LEG (Laboratorio de Estatistica e Geoinformacao) Universidade Federal do Parana Caixa Postal 19.081 CEP 81.531-990 Curitiba, PR - Brasil Tel: (+55) 41 3361 3573 VOIP: (+55) (41) (3361 3600) 1053 1066 Fax: (+55) 41 3361 3141 e-mail: paulojus AT ufpr br http://www.leg.ufpr.br/~paulojus
On Sat, 13 Nov 2010, kapo coulibaly wrote:
I?m using geoR to interpolate hydraulic conductivities. I constructed the variogram using the log transform as follows: dummy.var<-variog(dummy.geo,max.dist=40000,uvec=25,lambda=0) # Then I fitted a spherical model using eyefit parameters as starting parameters dummy.param<-eyefit(dummy.var) param1<-variofit(vario=dummy.var, ini.cov.pars=dummy.param[[1]]$cov.pars, cov.model = dummy.param[[1]]$cov.model,nugget=dummy.param[[1]]$nugget) spatPara<-krige.control(type.krige="ok",obj.model=param1) # I then interpolate across the map InterMap<-krige.conv(dummy.geo,loc=loc,krige=spatPara) Ma question is why are my interpolated values higher than the actual measurements. I expected the interpolation to honour measurement points at least. Am I missing something? Thanks [[alternative HTML version deleted]]