ABSTRACT
This chapter treats the gravity and gravity-type models, still not widely recognized by social scientists, as reflecting basic spatial behavior of society. It extensively develops the rationales of spatial choice models; emphasizing the discrete choice problem of an individual behaving unit and taking into account both spatial awareness and spatial information processing. The chapter examines interregional and interurban migration studies, examining hierarchical information processing use and interesting variations of the strict gravity model. Since 1960, a very large array of gravity and spatial interaction models has evolved. They relate to many different kinds of interactions, some purely theoretical but much more frequently interactions concerned with everyday problems and planning for which useful applications have been sought. The chapter finally examines applications of location-allocation models wherein an optimization framework is employed to identify both the optimal site for a single facility and the best set of sites for a network of facilities wherein forces for clustering and decentralization are examined.
