An Overall Urban System Assignment Papers.
Following a half century of popularity, central place theory experienced 20 years of neglect when the new urban system theory of network modeling gained attention at the beginning of the 1990s. However, central place theory remains valid, and it seems there has been a reemergence with it.An Overall Urban System Assignment Papers.
Using the Greater Pearl River Delta (Greater PRD) as an experimental study region, this paper intends to present an empirical study that validates central place theory and shows that it can be integrated into an overall regional urban system. The study uses the compound Central Place Importance (CPI) to evaluate whether there is a hierarchy among the urban centers within the study area. The results indicate the existence of a hierarchy. Furthermore, empirical observation finds distinct complementarity relationships, rank-size distributions, and co-operative actions between the different cities, thus substantiating the claim that central place theory can be incorporated into an overall regional urban system. Besides, the presence of the densely distributed modern infrastructure system also appears to constitute a dimension of the overall urban system. There need further theoretical and empirical studies in order to support this proposition.An Overall Urban System Assignment Papers.
Central Place Theory, Network Urban System, Overall Urban System, Central Place Importance, Complementarity, Rank-Size Distribution, Co-Operation, Greater Pearl River Delta
1. IntroductionUrban systems studies have evolved for almost two centuries since von Thunen published the famous book Der isolierte Staat in 1826. Important contributions have been made in many disciplines. Although the urban network idea seems becoming popular due to advanced technologies and economic globalization, traditional theories such as central place theory (CPT) still work and even have signs of reemergence.An Overall Urban System Assignment Papers. Compared to many scholars who assert that central place theory have outdated and have been supersede by theories such as new economic geography in explaining the spatial structure and intercity relationships of urban systems, a few researchers claimed that CPT still have merits, and can be part of the modern complicated urban system paradigm. Parr stated that the urban system of a region comprises two distinct components: activities governed by central place theory principles and activities influenced by specialized-functions, both helping to form the overall urban system together  . Meijers believed that there should be a sequential link between CPT and urban network model  .The purpose of this paper is to demonstrate that central place theory not only works, but also can be integrated with the emerging urban network idea. This will be achieved through the concept of overall urban system, and through the definition and implementation of a synthesized index of Central Place Importance (CPI), which will use the Greater Pearl River Delta as an empirical study area.2. Theoretical Fundamentals2.1. From Central Place to Network Urban SystemOriginally formulated by Walter Christaller  and thereafter developed by August Lösch  , central place theory (CPT) provides an explanation for the number, size, spacing, location and functional content of settlements within a sub-national or regional area.Since the pioneering formulations of Christaller and Lösch, the central place model has been elaborated, extended and criticized by many researchers. The major elaborations have essentially involved relaxing the restrictive assumptions upon which central place theory was based.An Overall Urban System Assignment Papers. Central place theory’s inability to accommodate the processes of change and its anachronistic assumptions has been identified as significant shortcomings  . CPT has also been challenged because of its somewhat weak explanation for the emergence of the hierarchy and its lack of a solid microeconomic foundation  . Furthermore, even when extended, the central place model is unable to address the location of economic activities that are not market-oriented and therefore not governed by principles of centrality.Despite the many endeavors and accomplishments of numerous researchers, the basic theoretical principles behind the theory remain, although it has encountered increasing obstacles over time. However, these deficiencies do not require the abandonment of central place theory but rather indicate the need for a broader framework that can subsume the central place model  .The network urban system model appeared during the last decade of the 20th century, although its basic principles can be traced back to the concept of the “dispersed city”  . Camagni and Salone  defined “city networks” as systems of horizontal, non-hierarchical relationships among specialized centers that provide externalities from complementarity or from co-operation among centers. Kloosterman and Musterd  described “polycentric urban regions” as collections of historically distinct, administratively and politically independent cities that are located in close proximity to one another and that are well connected through infrastructure. Obviously, this urban network theory has at least two features that better describe the spatial distribution and arrangement of urban economic activities: complementarity, different urban centers fulfill different and mutually beneficial roles; and co-operation between different settlements.2.2. A View of the Overall Urban System2.2.1.An Overall Urban System Assignment Papers. Some Missing ElementsAs originally defined by Christaller, the concept of centrality, wherein economic activities essentially include retail and/or service industries, is still valid. However, activities exist that contribute to urbanization and therefore help to mold an urban system but do not figure in the central place framework. Here, these activities are referred to as “specialized-function activities”. Functions relating to tourism, civil administration, public facilities, or military installations can form a basis for urbanization. In the case of resource exploitation, the existence of a resource does not guarantee its exploitation or the associated urbanization. Another important specialized-function activity is manufacturing. Manufacturing activity tends to be influenced by a variety of factors other than centrality. Firm agglomeration is another example in which the central place model does not play a role in locational choice and thereby influence urbanization because here, the dominating driving forces are agglomeration economies.2.2.2. An Overall Urban System Assignment Papers. The Overall Urban SystemThe idea of overall urban system was formally put forward by John B. Parr in 2002  . Except for combining CPT principles and specialized-functions, this overall urban system should have several distinctive features.The first characteristic is related to the nature of the hierarchy of centers. In a central place system, the hierarchy is successively inclusive, whereas in an overall urban system, the functional hierarchy is most likely more complicated and generally includes both central place activities and specialized-function activities”.The next characteristic is concerned with the socio-economic structure of the urban centers and how it varies with size. Two dimensions must be discussed. One concerns the degree of diversification or complexity represented by the various functions within an urban center. It is generally accepted that the larger the center is, the higher its level of diversification or complexity. This characteristic is very strong with respect to the central place component of the urban system, but it is also valid for the specialized-function component.Another aspect of the socio-economic structure of urban centers concerns the extent of differences between the profiles among the different settlements within an entire urban system, each settlement’s socio-economic structure, and the differences between (or distances to) other settlements. This aspect can be labeled “complementarity”.One further characteristic of this broader urban system concerns the size distribution of urban centers. Generally, the size distribution of urban centers conforms to the commonly known “rank-size distribution” formula, which can be expressed as follows:(1)where PR is the size (population) of an urban center of rank R, and P1 is the size of the largest urban center, while q is the slope of the function representing the extent of the center-size inequity or the level of interurban concentration.An Overall Urban System Assignment Papers. In fact, with respect to the size distribution of urban centers, another important aspect should be noted: the spatial distribution of urban centers across a region’s geographic territory. Should they be evenly distributed or unevenly distributed? To what extent? There appears to be an extremely wide variety of territorial distributions of urban centers across different regions around the world.Based on the previous discussion, it appears that the central place theory approach is wanting in a sufficiently large number of aspects, and it cannot be regarded as a general theory of the urban system. However, rather than replacing the central place model with the network model, it is widely accepted that a sequential link between the models exists, and path-breaking studies can be conducted not only to create a new theoretical paradigm but also to examine empirical case studies. Central place theory might provide a foundation upon which other facets (e.g., specialized-function activities) of the urban system can be superimposed.Here, an overall urban system concept is formulated based on the idea that the urban system of a nation or region comprises two quite distinct components. The first is concerned with the range of economic activity; the locational pattern for this activity is governed by the principle of centrality and can be approached in terms of central place theory. The second component involves specialized-function activities, whose locational pattern results from a diverse set of influences. Together, the two components help to form an overall urban system  . Thus, features of the network model and characteristics of the central place model are present within this overall urban system.In the following sections, empirical data from the Greater Pearl River Delta are presented and tested to verify the idea that the central place model and the network model can be integrated and that these two dimensions can form an overall urban system.3. The Greater Pearl River Delta Study Area and DataFacing the South China Sea to the south and located in a central position in coastal southern China, the Greater PRD study area is a relatively isolated region, with the Changsha metropolitan area 700 km to the north, the Xiamen metropolis 500 km to the east, and the city of Nanning 800 km to the west. The geographic range of this study area is between 21.6 and 24 degrees north latitude and 112 and 115.4 degrees east longitude. The area is 44,891.2 km2 and had a population of 61,861,000 in 2010. Administratively, the Greater PRD consists of eleven prefecture-level and upper administrative/political units: two sub-provincial level cities, namely Guangzhou, and Shenzhen; seven prefecture-level cities, namely Huizhou, Dongguan, Zhuhai, Zhongshan, Jiangmen, Foshan, and part of Zhaoqing; and two Special Administrative Regions (SARs, considered provincial level political units), namely Hong Kong and Macao (Figure 1).This study area’s natural endowments appear to be almost perfect, although there are few mineral deposits, such as oil and iron, for traditional industries. The loamy land, comfortable weather, abundant surface water, and long history of farming culture have made the Lower Pearl River Basin a productive region. Agriculture flourished in the past, and Guangzhou (the capital of Guangdong province) was always considered to be the most important commercial and cultural center in southern China. Since 1978, with the adoption of China’s policy of openness and reform, the Greater PRD has become a center of rapid economic growth and systemic reforms, a key destination for foreign investment, and a platform for China’s growing integration into the global economy. Within the mainland portion of the Greater PRD (except Hong Kong and Macao), per capita GDP grew at 17.9 percent annually between 1978 and 2000 and 13.4 percent annually from 2000 to 2008. An Overall Urban System Assignment Papers. Contributions from primary, secondary and tertiary activities in the area changed dramatically during the past three decades, from 25.8%, 45.3%, and 28.9% in 1980 to 2.4%, 50.3%, and 47.3%, respectively, in 2008.Figure 1. Location and physical geography of the Greater PRD study area.4. Methods4.1. Definition of the Network Urban SystemIn central place theory, an urban system consists of a hierarchical ranking of urban centers, associated market areas and transportation networks. A polycentric urban region can more or less be identified by structural characteristics such as the location of cities relative to each other and their size distribution. Urban networks could be considered to be an advanced type of polycentric urban region. There must be a certain level of functional integration and complementarity for a regional urban system to be justified as an urban network.A network urban system (overall urban system) can be defined as a nodal region that consists of nodes (cities, towns, firms, etc.), linkages between the nodes (infrastructure, ties), socio-economic complementarity relationships, interactions (flows) between the centers, and areas surrounding the nodes (hinterlands, including farmlands, ecological/environmental protection areas, etc.). An Overall Urban System Assignment Papers. Hierarchical relationships may exist between the urban centers (nodes), while complementarity relationships and spatial interactions between the urban centers must be present, at least to some extent    .The scale of a network urban system can be as small as the Randstad (less than 10,000 km2), or as large as the Yangtze River Delta (more than 100,000 km2). The distances between the urban centers range from dozens of kilometers to a little more than 100 kilometers. Nevertheless, the keys are the polycentric urban structure and the complex intercity relationships.An Overall Urban System Assignment Papers.