Sustainability has become a popular notion in current environmental policyanalysis. Various definitions of this concept can be found in the literature.Analytically, the notion is relevant in the integration of socio-economicdevelopments with environmental effects in order to obtain insight into (potential)environmental conflicts. Important in the operationalization of sustainabilityis the spatial as well as the temporal scale. This relates to so-called weak andstrong sustainability. These interpretations determine the degrees of freedom orthe trade-off possibilities for the policy maker. In environmental policy analysis - where'what if' questions are relevant - a quick and flexible exploration of theseconsequences is often needed. In this paper, the authors argue that GeographicInformation technology particularly if embedded in a DSS enviromnent can be avaluable instrument in sustainability analysis and in particular in exploring theconsequences of several more subjective aspects of sustainability analysis: e.g.,the application of various spatial levels of the sustainability constraint.