Hole-effect Models

A semi-variogram $/gamma({/boma h})$ is said to display a hole effect when its growth is not monotonic. The hole effect can appear on models with or without sills, cf. Figure 4.7.

Figure 4.7: Hole-effect Model.

Example 4.5: The Outputs in Figures 4.8 and 4.9 illustrate empirical variograms of the Copper and Nickel data from Table 2.7 how they are produced by a computer program (e.g. see Dutter, 1992[]). The numerical values with the number of pairs together with the minimum distance, the maximum and the averaged one, are listed in Tables 4.1 and 4.2. A corresponding graphic, Figure 4.8, shows a kind of hole-effect, while the nickel data in Figure 4.9 eventually indicate a nested structure. Both figures may also indicate a drift.

Table 4.1: Empirical Values of the Variogram of Copper Data.

Table 4.2: Empirical Values of the Variogram of Nickel Data.

Figure 4.8: Variogram of Copper Data.

Figure 4.9: Variogram of Nickel Data.