[R-sig-Geo] LDL factor

[Edzer Pebesma]

I tried out on the dataset (off-list), and found the following duplicate
point pair:

> coordinates(dataset)=~X+Y
> zerodist(dataset)
     [,1] [,2]
[1,]   82   84


On 07/05/2012 03:24 PM, Waldir de Carvalho Junior wrote:
> Hi
> I am having problem when try to use the krige function in R.
> I dont have duplicated points and the commands and the error message are:
> 
>> freg = arg.1~1 # regression formule> G<-gstat(id='dataset$ID', formula= freg, locations=~X+Y, data=dataset)> ev <- variogram(G, cressie=F, boundaries=c(seq(0,600,200),seq(800,5800,1000)))> vgm = fit.variogram(ev, vgm(4055, "Exp", 421,3774)) # adjustment> krige(id='dataset$ID', formula= freg, locations=~X+Y, data=dataset,newdata =dataset[,],model = vgm)[using ordinary kriging]
> 
> "chfactor.c", line 131: singular matrix in function LDLfactor()Error
> in predict.gstat(g, newdata = newdata, block = block, nsim = nsim,  :
>   LDLfactor
> 
> 
> I have a database of 208 points of soils samples, and i am trying to use
> gstat to estimate the clay content of surface layer.
> I read that the error maybe because of 2 points at the same location, but
> this is not the case.
> If someone can help, I could pass the database to some tests.
> Thank you
> Waldir
> 

-- 
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