Kriging uses the covariance structure of the field to estimate
interpolated values. The resulting interpolated field is optimal
in the sense of minimizing the variance among all possible linear,
unbiased estimates. Kriging requires a two step process - the fitting
of a semivariogram model function (of distance) followed by the
solution of a set of matrix equations.

The semivariogram calculation is carried out using the GSLIB library software
package (Deutsch and Journel, 1992). The user selects a
semivariogram function, sill, range, and nugget. Given these
parameters, a weighted average of the observation points is computed.

### References

Deutsch, C. V. and A. G. Journel (1992) GSLIB: Geostatistical Software
Library and User's Guide, New York, Oxford University Press.