A Theoretical Framework for Weight-Value Set Construction in Land Suitability Assessment

When using the rating and weighting (RAW) method in land suitability assessment, planners often substitute the theoretical weight-value range [0, 1] with a weight-value set, an ordered set of discrete values reduced from the continuous weight-value range. In constructing such a weight-value set, one needs to decide on how many weight values should be used (size of the value set) and where in the value range they should be placed (the choice of weight values). At present, one must make these decisions and defend their credibility on the basis of “professional judgments”, as a theoretical framework for such purposes is simply not available. Can a theoretical framework be established so that one can make these decisions systematically? If so, is it advantageous to use such a framework, instead of the existing methods, in constructing weight-value sets? In this paper these two issues are explored. I found that the theoretical weight-value range [0, 1] is actually sliced into segments; that in producing land suitability scores, weight-value sets that are constructed from these segments function just as effectively as the weight-value range; and that a five-rule framework comprised of these weight-value sets offers a higher level of efficiency and greater transparency than existing methods.