The nugget-effect approaches of SAKWeb for environmental modelling

Ordinary Kriging (OK) seems to achieve better spatial interpolation results than other methods regarding environmental pollution, for instance, although sampling distribution can turn out to be a problem. This latter issue leads to a crucial topic identified as the nugget-effect, the distance interval in which capturing spatial dependency is most important. SAKWeb^© developments have been made using four approaches to this factor: (1) with and (2) without nugget-effect, (3) micro-scale component and (4) measurement error inclusion that leads to a non-exact Kriging version. Although no spatial patterns can be found regarding which nugget-effect fits best, the possibility of simulating different on-the-fly models and comparing discrepancy among them is already significant in a W3 context.