Mapping Regional Shopping Center Trade Volumes in Atlanta, Georgia

MAPPING REGIONAL SHOPPING CENTER TRADE VOLUMES IN ATLANTA, GEORGIA Borden D. D en t* INTRODUCTION. The purpose of this paper is to report on a study that was conducted in Atlanta, Georgia, to determine the retail trade areas of eight large regional shopping centers distributed throughout the metropolitan area. A regional shopping center is defined as any planned center with at least one large department store. The present study focuses on the application of a method not frequently seen. An adaptation of the Huff model was devised, applied to the study area centers, and used to determine if the adaptations give reasonably reliable results in delimit­ ing retail trade areas in practical application, especially when compared to the familiar shopper survey technique. The study is not theoretical in its orientation; it was planned to develop a simple, yet firm, base upon which quick reliable estimates could be made regarding components of the retail landscape of any large metropolitan area. BACKGROUND NOTES. Geographers and others interested in the spatial aspects of marketing have carefully studied many of the char­ acteristics of retailing at the urban scale, especially with regard to trade area delimitation. One of the earliest certainly was William J. Reilly, who formulated what is now generally known as “Reilly’s Law of Retail Gravitation.” (1) Subsequently, others joined this vigorous research, notably Converse, who devised slightly altered versions of Reilly’s original formulations. These have been called the “New Laws of Retail Gravitation.” (2) Central place theory is implicit in Reilly’s research although it was done prior to Christaller’s Die zentralen orte in Siiddentochland . Fundamentally, these laws are not theoretically based, but are rigid, deterministic devices that allow researchers 1) to ascertain the relative strengths of two towns’ retailing activities, and by extension, 2) to determine breaking points which give approximations for develop­ ing trade areas around centrally located towns. The mathematical formu­ lations for these laws can be found elsewhere. (3) There have been fewer studies on retail trade area delimitation at the intra-city level. Yet from these it is clear that trade area delimitation at this scale is exceedingly difficult. The principal reason is that as shoppers have so many intervening opportunities, it becomes more burdensome to place them in one, well-defined trade area. (4) Most of •Dr. Dent is associate professor of geography at Georgia State University. The paper was accepted for publication in June 1972. 70 S o u t h e a s t e r n G e o g r a p h e r the research and practical application has been to develop trade areas around individual selling units, the chain-store supermarket for ex­ ample. (5) A few studies have dealt with intra-city trade areas of large shop­ ping centers, perhaps most recently by Brunner and Mason. (6) These researchers have found that in addition to the recognized factors of population, population density, purchasing power, and others, driving time is also a factor in consumer shopping center preferences. (7) Spe­ cifically, their findings for Toledo, Ohio, led them to conclude that the 15-minute driving time line was adequate for delimiting a center’s principal trade area (three-quarters of the center’s patrons resided within this area). Subsequent research by Cox and Cooke has supported the findings, but also points out that shopping center size and natural barriers around each center also influence trade area. (8) HufFs work is notable in this discussion because it was the basis around which the present research was formulated. Huff has stated that for intra-city trade area delimitation, Reilly’s law of retail gravitation fails because 1) it leads to a “fixed boundary” for trade areas, 2) there is no good reason to assume that a constant exponent in the equation would exist to describe all intra-urban consumer movement, 3) it incor­ porates little theoretical framework. (9) As a consequence of these stated limitations, he developed a more behaviorally oriented model, with the consumer at its center, to assist in developing shopping center trade areas. Huff states: “The analysis will utilize the conceptual prop­ erties of the gravity model, but its focus will be on the...