List with the calculated variogram. Components of the list
are: \$dist mean distance of the interval. \$vario calculated
value of the variogram. \$number number of datapoints in the interval.
In nearly all cases vagram will be the output from the program
Type of model. Default is spherical. It is currently the only
Method to use in automatic fitting. Allowed values are 1,2,3
and 4. Default value is 2. For further information see below.
If T the fitting is done interactively by plotting the
variogram on the screen and asking the user to select sill, range and nugget
by the locator function.
Sill of the variogram, or: Limit of the variogram tending to
infinity lag distances (wikipedia).