Spatial models have been in existence in the environmental and social sciences for a long time. More recently, specialised software for the capture, manipulation and presentation of spatial data, which can be referred to as `Geographical Information Systems' (GIS), have vastly increased the range of possibilities of organising spatial data by new and efficient ways of spatial integration and spatial interpolation. Coupled with the improvements in data availability and increases in computer memory and speed, these novel techniques give rise to new types of spatial models which exploit the technological potential now available, make better use of existing data, stimulate the collection of new data and open up new ways of working with geographic information. This book explores the potential and impact of GIS on spatial modelling.