Using GIS and outranking multicriteria analysis for land-use suitability assessment

Land-use planners often make complex decisions within a short period of time when they must take into account sustainable development and economic competitiveness. A set of land-use suitability maps would be very useful in this respect. Ideally, these maps should incorporate complex criteria integrating several stakeholders' points of view. To illustrate the feasibility of this approach, a land suitability map for housing was realised for a small region of Switzerland. Geographical Information System technology was used to assess the criteria requested to define the suitability of land for housing. An example dealing with the evaluation of noise levels illustrates the initial steps of this procedure. Because the required criteria are heterogeneous and measured on various scales, an outranking multicriteria analysis method called ELECTRE-TRI was used. However, using it to assess the suitability of any point in a territory was impractical due to computational limitations. Therefore, a mathematical function to evaluate closeness relationships and classify the study area into homogeneous zones was used. This function is compatible with the outranking function of ELECTRE-TRI used to assess the suitability index. The resulting maps lend efficient support to negotiation and are very useful in dealing with inherent conflicts in land-use planning.