Geographic Information Systems mainly tend to be two dimensional, thus limiting the applications. As GIS are being developed, researchers and practioners are finding new ways of making GIS three dimensional, even four dimensional in some instances, increasing their usability. This book focuses on the way in which GIS could be made `multidimensional' based on the modelling limitations of current 2D GIS. It suggests extending GIS to incorporate the third and fourth dimensions, as well as time (spatio-temporal GIS), using a variety of programming techniques and discusses current examples of multidimensional GIS.