Sample variogram (gstat variogram conventions)

Pairs binned into \((b_k, b_{k+1}]\) (default cutoff a third of the bounding-box diagonal, width cutoff/15); estimators classical, cressie (Cressie and Hawkins 1980), mad (Dowd 1984), pairwise_relative and relative (Isaaks and Srivastava 1989); covariogram (with gstat's lag-zero row); pseudo cross-variogram against z2 (Myers 1991); indicator variogram of z <= threshold; directions alpha (degrees clockwise from north) with tolerance tol_hor; cloud.

Usage

SampleVariogram(
  z,
  coords,
  cutoff = NULL,
  width = NULL,
  boundaries = NULL,
  alpha = NULL,
  tol_hor = NULL,
  estimator = "classical",
  covariogram = FALSE,
  cloud = FALSE,
  z2 = NULL,
  threshold = NULL
)

Arguments

z

Values.

coords

Two-column matrix.

cutoff, width, boundaries

Distance bins.

alpha

Directions in degrees.

tol_hor

Angular tolerance.

estimator

Estimator name.

covariogram

Estimate the covariogram.

cloud

Return the variogram cloud.

z2

Second variable (pseudo cross-variogram).

threshold

Indicator threshold.

Value

List with np, dist, gamma, dir_hor (or the cloud).

References

Cressie, N. and Hawkins, D. M. (1980). Robust estimation of the variogram: I. Mathematical Geology 12, 115-125.

Myers, D. E. (1991). Pseudo-cross variograms, positive-definiteness, and cokriging. Mathematical Geology 23, 805-816.

Examples

SampleVariogram(c(1, 2, 4, 3), rbind(c(0, 0), c(1, 0), c(0, 1), c(1, 1)), boundaries = c(0,
  1.2, 1.5))
#> $np
#> [1] 4 2
#> 
#> $dist
#> [1] 1.000000 1.414214
#> 
#> $gamma
#> [1] 1.5 2.0
#> 
#> $dir_hor
#> [1] 0 0
#>