Typology of City-based Regions in Urban and Regional Studies: with an emphasis on concept of “Majmoo-e-ye shahri” in Iran

Before the beginning of the twentieth century, two concepts of "City" and "Village" (rural areas) and in a few cases, "Metropolis" would have to describe sufficiently residential forms and spatial development of national territories. But the development of urbanization in the twentieth century in both micro and macro scale caused formation of new phenomena in the spatial organization of the land. Responding to the formation of new spatial phenomena, scholars in spatial science start to conceptualize what were emerging. Reflects of spatial changes in micro scale can be traced in the construction of new concepts like New towns, Satellite cities , Suburbia and more recently Edge cities, Exurbia and Exopolise, Technoburbs and Technopoles that all were emerging in rural-urban fringe of great and pioneer cities. The second category of conceptualization (macro scale) were reflected in creating concepts such as Metropolis, Conurbation, Metropolitan area, City - region, Megalopolis, Mega city, Mega city-region, Functional urban region, Urban agglomeration, Metropolitan region, Polycentric urban region … all conceptualize macro scale spatial phenomena. These types of great regional substance were resulted from, a) initial expansion of the city or metropolis, b) joining together independent neighboring urban areas and, c) existence of functional interaction between physically separate urban and rural areas. In fact, macro scale phenomena were result of expansion, joining together and functional interaction of micro scale phenomena explained above. Definition of macro scale spatial concepts and also providing a kind of typology of these phenomena are the main theme of present paper. The necessity of this typology is nested in the existence of confusion in finding correspondence of real world macro scale phenomena with equivalent accepted concepts among different kind of users. One of the major misconceptions in Iran is seen in finding equivalent concepts for "Majmoo-e-ye shahri" which is considered in our official documents as equivalent of "Conurbation" while it is not. The most important note here is that the effects of these misunderstanding will not be limited to the theoretical field but it will appear in practice. Because, it is evident that finding proper strategy and management systems for a Conurbation will be different from a proper one to a Metropolitan region that is the best concept for naming Majmoo-e-ye shahri in Iran . This paper attempt to reviews prevalent macro scale concepts in literature of urban and regional studies. Twelve concepts were listed at the end of a wide exploratory study. It should be reminded that some of these concepts, their definitions and application in the literature also have some degree of confusion. It seems that there is not a clear distinction between some concepts. Regardless, our typology ended in categorization of all reviewed macro scale concepts into three class: a) the concepts focused on a great built city, b) concepts focused on a typical and coherent city -region and, c) the concepts focused on several independent city regions which are adjacent but physically separated. All concepts in these three categories are distinct according to criteria such as physical cohesion and continuity, intensity of functional interaction and their spatial scale.