Compute Spatial Variogram

DESCRIPTION:

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

USAGE:

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

REQUIRED ARGUMENTS:

krig
trend-surface or kriging object with columns x, y, and z
nint
number of bins used

OPTIONAL ARGUMENTS:

plotit
logical for plotting
...
parameters for the plot

VALUE:

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

SIDE EFFECTS:

Plots the variogram if plotit = T

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.

SEE ALSO:

EXAMPLES:

topo.kr <- surf.ls(2, topo)
variogram(topo.kr, 25)