ABSTRACT
Most environmental models take as their input a sequence of parameters that are observed at only a limited number of points. There are many practical circumstances in which one wishes to extend these models to make spatially continuous predictions. In such cases, the question arises whether to interpolate the inputs to, or outputs from a model into an output grid (Figure 18.1). The issue is important because the two approaches differ in the efficiency and quality of the results that are produced. With the number of situations in which dynamic environmental models are being linked to GIS now expanding rapidly, this is a generic and as yet under researched question that the GIS and environmental modelling communities need to tackle.
