[R-sig-Geo] problems in anisotropy detection

Emanuele Barca em@nue|e@b@rc@ @end|ng |rom b@@|r@@@cnr@|t
Sat Jul 13 07:32:22 CEST 2019


Dear friends,

I have a dataset of hydraulic heads, mydata = <X, Y, HH, Z> and i would 
like to check for anisotropy.

In R I found 3 functions to carry out such task:

1. likfit

x_geodata <- as.geodata(mydata, coord.cols = 1:2, data.col = 3,
                         covar.col = 4)
fit_mle  <- likfit(x_geodata,
                    fix.nugget = FALSE,
                    cov.model = "exponential", psiA = 0, psiR = 1,
                    ini = c(var(Y), 1), fix.psiA = FALSE, fix.psiR = 
FALSE,
                    hessian = TRUE)

that detects no anisotropy.

2. estimateAnisotropy

mydata.sp <- mydata
coordinates(mydata.sp) = ~ X + Y
estimateAnisotropy(mydata.sp, depVar = "LivStat", "LivStat ~ Z")

that returns the following

[generalized least squares trend estimation]
$`ratio`
[1] 1.340775

$direction
[1] -35.29765

$Q
               Q11          Q22          Q12
[1,] 1.926136e-05 2.329241e-05 5.721893e-06

$doRotation
[1] TRUE

finally,

3. estiStAni

vmod1 <- fit.variogram(vgm1, vgm(18, "Ste", 1300, 0.78, kappa = 1.7))
estiStAni(vgm1, c(10, 150), "vgm", vmod1)

that returns an error:

Error in `$<-.data.frame`(`*tmp*`, "dir.hor", value = 0) :
   replacement has 1 row, data has 0.

I am very puzzled, can anyone help me understanding if there is 
anisotropy in my dataset?

thanks

emanuele



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