gstat warning message from cross validate linear model
You are using a variogram that is permissible in 1D, but not in 2D (linear with sill). This will generate negative variances, from which the square root (sqrt) is computed in order to produce z scores. The advice is to not use this model for data spanning more than one dimension; the software, or its author, assumed you know this.
On 04/07/2014 08:59 PM, Moshood Agba Bakare wrote:
Hi, The four variograme models below are fitted to the same dataset. I got a *warning message *while cross validating a fitted linear variogram model as Warning message:In sqrt(ret[[var.name]]) : NaNs produced from this R script lin.kcv <- krige.cv(yield ~ 1, canmod.sp, model = lin.var,nmax=100, nfold = 5) what is the meaning of this warning? Each time I run this R script, I got different values for the cross validation statistics of linear. Model RMSE MSDR Spherical 0.66 1.61 Gaussian 0.62 3.17 Exponential 0.65 1.91 Linear 95.91 83.25 These valueslook very strange compared to others because of warning message above. How do I explain this? I made effort to redefine my nfold to be 10 but still give the same warning. Thanks Moshood
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