Optimization of sampling locations for variogram calculations

A method is presented and demonstrated for optimizing the selection of sample locations for variogram estimation. It is assumed that the distribution of distance classes is decided a priori and the problem therefore is to closely approximate the preselected distribution, although the dispersion within individual classes can also be considered. All of the locations may be selected or points added to an existing set of sites or to those chosen on regular patterns. In the examples, the sum of squares characterizing the deviation from the desired distribution of couples is reduced by as much as 2 orders of magnitude between random and optimized points. The calculations may be carried out on a microcomputer. Criteria for what constitutes best estimators for variogram are discussed, but a study of variogram estimators is not the object of this paper.