Weighing decision factors in a GIS-assisted DSS : application in upland development planning and allocation in the Philippines

Abstract

A prototype GIS-based procedure for setting priority sites for upland development based on a hierarchical integration of ecological, social and economic criteria and involvement of stakeholders in the selection process was developed for the Okoy-Banica watershed area in the Philippines. The basic steps involve the preparation of digitised data sets, derivation and classification of ecological, social and economic factor maps, elicitation of factor weights among stakeholders of the study area and encoding the factor weights into the factor maps, and overlaying and computing the factor maps to generate the decision/priority maps for upland development in accordance with the study model.

The key aspect of the study is the investigation of the impact of factor weights being assigned by different stakeholder groups as a departure from the usual practice where experts assign the factor weights. Factor weights produce the numerical scale of judgement in order to quantify and use mathematical operations to produce objective decisions using GIS. In a GIS-assisted DSS, factor weights link the human dimension of decisions with the physical site attributes.

Results of the study reveal, that the statistical test on priority rating of selection criteria by different stakeholder groups yielded a generally significantly different responses and that the resulting factor weights when encoded and overlaid in GIS produced variations on the extent and location of selected priority sites. The study shows the potential use of the consensus or multi-sectoral approach to factor weight assignment as a key towards generating multi-sectoral involvement in ensuring success of upland development projects. It also illustrates the important role the factor weights play in a GIS-assisted decision making and in the integration of people's participation towards ensuring sustainable development consideration in the planning and allocation process of upland development projects.