The social and spatial structure of urban and regional systems
The social and spatial structure of a given urban or regional systems have played important roles ever since cities and towns first came into existence, their role in the evolution of townscape has changed and evolved over the years, sometimes driven by planning and sometimes by circumstances. First of all, for a better understanding of the research terms, looking at the research title, four articulated variables of the study can be identified, that are the structures of: urban social, urban spatial, regional social and regional spatial systems. Though they are different systems at various levels, but at the same time they are interconnected in a way that each system affects the other in terms of its characteristics, regulations, and organization. Since the total population and the average density of a given area are the basis for any socio-spatial structure study, the difference between the urban and regional systems will be evident beside of the different scales in the first place.
After clarifying the distinctive terms of the study, it is important to introduce definitions of the interrelated spatial structure and social structure in both levels. The urban spatial structure, to start with, examines the order and relationship among physical elements and land uses in urban areas as they evolve from interaction among the key systems and pass through transformations in time and space (Garba, 2013). Thus, it basically considers the location of different activities as well as their relationships. This spatial structure arrangement serves as a support for social structure activities that are functionally related hierarchy to the various elements that form the structure of urban space (residential areas, services and business areas, industry, and transportation network). Moreover, drawing on (Coiacetto, 2006) the social structure of the city is a variegated pattern of social groupings that tend to be characterized by common features such as socioeconomic status, age, life stage (e.g. child rearing), ethnicity, and lifestyle.
Three classical theories of spatial organization were constructed to examine single cities and they do not necessarily apply to metropolitan areas so common in today’s world (Garba, 2013), these theories/models are Burgess-Concentric zone theory, Hoyt-Sector theory and Ullman and Harris-Multiple nuclei theory (figure 1). However, these models had their limitations as they do not reflect the current situation of our cities, and they do not adequately explain the distribution of social activity around urban areas.
Figure 1: classical theories of spatial organization (Burdett, 2014)
Looking at cities urban spatial structure, it can be recognized that the most distinguished node is the central area with the agglomeration of core activities, which is the CBD (Central Business District); its emergence is the result of an historical process that has changed the urban form and the location of central activities. According to the core location and function one can trackback the evolution of spatial structure of a city from the pre-industrial era with one centric CBD, to the industrial revolution era and beginning of expanding the center, and finally the contemporary era with the emergence of suburban areas and new centers.
Figure 2: The Evolution of the Spatial Structure of a City (Rodrigue, 2013)
Mainly four models of the urban spatial structure can be characterized by its level of centralization and clustering (figure 3); they are namely, the monocentric, the polycentric, urban village, and the composite models.
Figure 3: The Models of the Urban Spatial Structure (Hayward, 2013)
Moving to the regional level, first it is important to examine the concept of region in order to put it in context. Regions are commonly organized along an interdependent set of cities forming what is often referred as an urban system (Rodrigue, 2013); they usually contain areas that have distinguishing characteristics from other areas. The spatial structure of most regions can be subdivided in three basic components: locations of specialized industries, service industry sites, transport nodes and links. Jointly, these elements define the spatial order of the region, mostly its organization in the hierarchy of relationships involving the social structure with the flows of people, freight and information (Rodrigue, 2013). Also, it is important to note that the same concept of centralization and dispersion apply on a regional level, but on a different scale (figure4). A polycentric regional spatial structure refers to the situation in which the cities in the region are relatively equal in size. A dispersed regional spatial structure relates to the situation in which a large part of the population is not living in cities but spread out across the territory in a non-concentrated pattern (Burger, Meijers, & van Oort, 2013).
After examining all of the research terms, it is interesting to point out the relationship between them and where they possibly interrelated. Three conceptual categories of urban, regional socio-spatial organization can be observed in: Central places / urban systems models, Growth poles, and Transport corridors (Rodrigue, 2013).
Figure 4: Dimensions of Regional Spatial Structure (Burger, Meijers, & van Oort, 2013)


