Classical Matheron estimator: half the average squared difference
of values within each distance bin.
Usage
morie_spatial_variogram(coords, values, n_bins = 15L, cutoff = NULL)
Arguments
- coords
Two-column matrix (or data frame) of coordinates.
- values
Numeric vector of observations.
- n_bins
Number of distance bins (default 15).
- cutoff
Maximum distance considered (default one third of the
maximum pairwise distance, the gstat convention).
Value
A data frame with dist (bin centre), gamma
(semivariance), and np (pair count per bin).
References
Matheron, G. (1963). Principles of geostatistics.
Economic Geology, 58(8), 1246–1266.
Examples
set.seed(1)
coords <- cbind(runif(60, 0, 10), runif(60, 0, 10))
values <- coords[, 1] * 0.5 + rnorm(60, 0, 0.3)
str(morie_spatial_variogram(coords, values), max.level = 1)
#> 'data.frame': 14 obs. of 3 variables:
#> $ dist : num 0.388 0.647 0.906 1.165 1.424 ...
#> $ gamma: num 0.0324 0.102 0.1474 0.1758 0.1261 ...
#> $ np : int 14 16 25 27 28 43 43 57 48 60 ...
