n by 2 matrix with a set of locations, typically a
prediction grid
coords
data coordinates
krige
a list defining the model components and the type of
kriging. It can take an output to a call to krige.control or
a list with elements as for the arguments in krige.control.
Value
An scalar with the value of the global variance
References
Isaaks, E.S and Srivastava, R.M. (1989) An Introduction to
Applied Geostatistics, pag. 508, eq. 20.7. Oxford University Press.