Figure 6.  Predicted vs measured for ordinary kriging (OK) using the G₃₀ data set and for IDW with a distance exponent of 2 using each data set (i.e. G_30, G_61a-d, and G_91a-d).  The regression lines are shown as solid lines and the first bisector as a dashed line.  The rmse of the prediction of each prediction is given.