An Evaluation of Alternative Spatial Models

Abstract

struct having space as one component.' Evaluation will be limited to economic models involving one or more commodities (primary, intermediate and/or final goods) and depicting one or more of the following economic activities: the regional location and level of production -including primary (farm) and/or secondary (processing) stages; shipping patterns of primary, secondary, and/or final goods; the regional level of consumption of final goods; and the relative and/or absolute level of regional prices. This includes formulations commonly called analysis models, interregional competition models, models, spatial equilibrium models, and plant location models. Model Classification and Description As the number of alternative models prohibits individual evaluation (without being too discriminating, one can list well over 500 separate formulations), they must be grouped according to some common characteristics. Although several meaningful classifications could be used, the usual distinction and the one followed here is to group the models into: standard equilibrium formulations using demand and supply relations and activity analysis models involving physical production activities and demand relationships. The two groups are not mutually exclusive-both may portray partial or complete equilibrium, their representation of shipping and consumption activities are similar, and the simplest model of each is the standard transportation model with preassigned regional quantities produced and consumed. In the standard equilibrium type model,2 discrete regions are defined and all production and/or consumption in each region is assumed to take place at one point (implicitly assuming homogeneity throughout the entire region). Quantities supplied and demanded in each region may be preassigned or a function of local prices and relevant exogenous variables, and unit transfer costs are specified between each producing and con