A meta-study of research related to urban and regional spatial structures in Iran; from 2001 to 2019

In recent decades, the study of spatial planning in general and “spatial structure” in particular has taken a special position in international references. The review of related theoretical texts published in recent decades shows great changes in this area. Most of the research has reviewed and scrutinized the spatial structure in the theoretical literature and international empirical research (Parr, 2013; Meijers, 2005; Davoodi, 2003; Guillain et al., 2006; Cao, 2016; Gebhardt, 2016; Goletz, 2016). In national references, new concepts and foundations have been explored in the field of spatial structure in particular and spatial planning in general. On the one hand, the diversity and variety of research conducted in this field in national references, the contradictory results obtained from some of the research, and the lack of a single finding may imply the uselessness of the conducted research and the waste of time and money. On the other hand, the results confuse some scientific societies and theorists, policymakers, planners, and decision-makers. Therefore, a meta-study approach is used to remove such conditions in research methods and their revision process. By using a meta-study, the present study aims to review the national research in the field of spatial structure to identify and examine theoretical and scientific gaps and address the strengths of research. Finally, by combining and summarizing the studies on spatial structure, the theoretical frameworks of reviewed studies are explained.

The present research is a developmental-applied study in terms of objective and includes quantitative and qualitative aspects in terms of type and nature of data. According to the characteristics of the research topic, this study is descriptive-analytical research carried out using a meta-study research method.

The content analysis of the reviewed studies showed that in these studies, four approaches had been applied to analyze the spatial structure. They include hierarchical, systemic, relational-synergistic, and contextual approaches. There are also three perspectives on “spatial structure”. The origin of these perspectives is rooted in the areas addressed in the theoretical foundations of studies. In studies on topics such as “monocentric, polycentric and scattered patterns”, the perspective on “spatial structure patterns” was applied to analyze the spatial structure. In studies on topics such as “centralized, decentralized, scattered, compact, random, sprawl, fragmented and leapfrog patterns”, the perspective on “spatial structure development patterns” was applied. Those articles focusing on topics such as “linear, island, cluster, symmetrical, correlated, radial, sector, complex, porous patterns” have analyzed the spatial structure using the perspective on “form patterns of spatial structure.” Moreover, the analysis of studies showed that the confusion of topics and concepts has taken place in the field of spatial structure. In many studies, the concepts of spatial growth patterns and spatial form patterns have been used instead of spatial structure patterns, indicating a misunderstanding of key concepts in the field of spatial structure. The analysis of studies also showed that various factors and driving forces- internal factors including “backgrounds and contexts, economic, demographic, social dimensions and infrastructure” and external factors and drivers of development including “government policies and decisions- spatial planning policies, globalization - global processes and economic rivalries”- influence the formation and change of the spatial structure of cities and regions.

In the general review, it can be stated that the study of the spatial structure has become an important issue in Iran only in the last two decades. About 80% of these studies have been conducted in less than a decade, indicating the emergence of this concept in the spatial planning system of Iran. On the other hand, 87% of the studies have an applied-developmental nature, and only 13% have addressed basic concepts, indicating the poor scientific development of this concept in applied-developmental studies. Among the effects of this shortcoming, one can mention the low-quality and inadequacy of the theoretical foundations presented in the studies, which was observed in 42% of the reviewed studies, according to the present study results. Only 34% of the studies were evaluated well in terms of theoretical foundations. Some significant weaknesses identified in the qualitative evaluation of studies include less use of up-to-date and reliable references, the lack of proper coherence between the objectives and research questions and theoretical foundations, and improper use of theoretical concepts and foundations. There is also a particular weakness in focusing on the approaches. There is a lack of knowledge in the reviewed studies, and most of them have expressed related approaches and theories without having any theoretical knowledge. On the other hand, more than 65% of the studies have relied on a morphological approach rather than land use, functional, and combined approaches. Therefore, in future research, it is required to pay more attention to the development of theoretical and approach concepts, structures, and frameworks and analytical approaches to the spatial structure to fix existing gaps. Also, in the analysis of geographical distribution, it was found that most of the studies focused on Tehran metropolitan area and Tehran metropolis and other geographical areas have been less studied, indicating a weak balance in exploring the different geographical areas of Iran. Of the four spatial scales, 54% of studies were performed at urban and metropolitan scales, and researchers have less considered other spatial scales.