[R-sig-Geo] warning: singular in variogram fit

[Edzer Pebesma]

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warning: singular model in variogram fit. site:stat.ethz.ch

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On 06/16/2013 11:54 AM, Israel Ikoyi wrote:
> Dear R-sig-Geo,
> 
> I am trying to fit the the "Materon' model to my data with this command:
> 
> # define gstat object and compute variogram:
> # mal = subset(mal, !is.na(mal$Zntot.s)) # needed if missing values
> g = gstat(id = c("Zntot.s"), formula = Zntot.s~1, data = mal)
> vg = variogram(g)
> # vg = variogram(g, boundaries = c(15,25,45,70,100,150,200,250,300))
> windows(width = 8, height = 6)
> plot(vg, plot.numbers = TRUE)
> 
> # choose initial variogram model and plot:
> vgm = vgm(nugget=0, psill=0.5, range=140, model="Mat", kappa = 0.9)
> plot(vg, vgm)
> 
> # fit variogram model:
> vgm = fit.variogram(vg, vgm)
> windows(width = 8, height = 6)
> plot(vg, vgm, main = "Variogram Zntoy.s")
> vgm
> 
> Then i get this warning: singular model in variogram fit. What does it mean and how do i solve the problem? 
> 
> Thank you
> 
>  
> Kind regards,
> 
> ISRAEL O. IKOYI
> MSc. Thesis Research Student
> Wageningen University 
> Department of Soil Quality 
> P.O. Box 47 
> NL-6700 AA Wageningen 
> The Netherlands
> 
> 	[[alternative HTML version deleted]]
> 
> 
> 
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> 

-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
83 33081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de