variogram {spatial} | R Documentation

## Compute Spatial Variogram

### Description

Compute spatial (semi-)variogram of spatial data or residuals.

### Usage

    variogram(krig, nint, plotit = TRUE, ...)

### Arguments

`krig` | trend-surface or kriging object with columns `x`, `y`, and `z`
`nint` | number of bins used
`plotit` | logical for plotting
`...` | parameters for the plot

### Details

Divides range of data into `nint` bins, and computes the average squared difference for pairs with separation in each bin. Returns results for bins with 6 or more pairs.

### Value

`x` and `y` coordinates of the variogram and `cnt`, the number of pairs averaged per bin.

### Side Effects

Plots the variogram if `plotit = TRUE`

### References

Ripley, B. D. (1981) Spatial Statistics. Wiley.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### See Also

`correlogram`

### Examples

    data(topo, package="MASS")
    topo.kr <- surf.ls(2, topo)
    variogram(topo.kr, 25)

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