The Nature of the Land Area of the City Center in Regional Planing Four spatial phenomena at the Metropolis TehranAbstrac

Land in the city center is the outcome of relationships and physical performance. The extension of these relations complicates the understanding both spatial phenomenon and regional planning. This study has surveyed the four terms in regional planning (Metropolitan Region, City-Region, Functional Urban Region and Polycentric Urban Region) and it has paid attention to the explanation of every phenomenon’s nature by using of the comparative analysis method according to functional and morphological factors. The needed information has been collected in the documentary- library method. The Statistical methods and the models of planning such LQ and activity rate are used to adjust the spatial model of Tehran metropolis and its surrounding areas with the obtained theoretical framework. Thus, the optimized spatial model of Tehran metropolitan and its around has been presented in different scales. The findings show that Tehran metropolis accept the central roles not only in the complex scales such as national and regional but also between them. So, the existence of various patterns of functional interactions between Tehran metropolitan and its surrounding cities can add a new spatial nature to this metropolis and its surrounding areas. From physical viewpoint about the spatial phenomena, the urban based territories seem morphologically closer together. It is deserved that the spatial phenomena has been focused on the complex systems of morphological, functional, relational and political factors. The spatial nature of Tehran metropolis and its surrounding areas is studied in each of models. Therefore, three concepts of metropolitan region, functional urban region and city-region introduced as acceptable and definable spatial models in the various optimized scales.