The practise of variogram fitting should be treated as more than just a curve fitted to data points exercise. The experimental variogram can be impacted by lack of data, sampling bias, clustering and the proportional effect. A seasoned resource geologist will already have a variogram in their mind prior to doing any exploratory variography. The points plotted on the graph are merely a confirmation of the hypothesis

The objective of this exercise is to try and picture what the variogram model for the different spatial grade distributions looks like. The steps you should follow are as follows:

* Select the appropriate variogram model, nugget effect and range for the line A-B.
* Assume the figures measure 100m by 100m.
* Think of the colours as representing the full spectrum of grade ranges. Try and imagine which colours represent the mean and standard deviation (plus and minus).
* Look at the grade patterns and picture anisotropy ratios, directions of continuity and any other features you observe.