Combining Fuzzy Sets and Databases in Multiple Criteria Spatial Decision Making

Spatial decision making is a fundamental function of contemporary Geographic Information Systems (GIS). One of the most fertile GIS development areas is integrating multiple criteria decision models (MCDM) into GIS querying mechanisms. The classic approach for this integration has been to use Boolean techniques of MCDM with crisp representations of spatial objects (features) to produce static maps as query answers. By implementing: 1) fuzzy set membership as a method for representing the performance of decision alternatives on evaluation criteria, 2) fuzzy methods for both criteria weighting and capturing geographic preferences, and 3) fuzzy object oriented spatial databases for feature storage, it is possible to visually represent query results more precisely. This will allow decision makers to be more informed, and thus, more correct. We conclude the paper with future research directions and implementation prototype strategies.