Analysis of Spatial Expansion Challenges in Metropolitan Areas with a National Security ApproachCase Study: physical-spatial challenges in Tehran Metropolitan Area

The Spatial Expansion of the metropolitan area of Tehran has taken place in recent decades with an accelerated speed and a heterogeneous character. With this approach, the aim of the current research is to analyze the challenges of the metropolitan area of Tehran with the approach of national security and its explanatory-analytical implementation method. In this research, five types of challenges include informal settlements; annexation, integration and depopulation of the village; land use change; Centralization and rapid and heterogeneous urbanization were explained and it was found that the challenges under the influence of two factors threaten national security; The first factor is related to the national nature of the metropolitan area of Tehran and the second factor is related to the anti-security nature of the challenges.The results show that physical-spatial challenges play an effective role in threatening national security, but their effectiveness is different. The challenge of informal settlements has the greatest impact on national security, and the challenge of annexation, integration and depopulation of villages poses the least threat to national security among the examined challenges. The most important result obtained from the research is a challenging and security look at the Spatial Expansion model in the metropolitan area of Tehran and finding new windows from the concept of security of Spatial Expansion issues. In other words, space development has been considered as the origin of processes that threaten national security, but they have been neglected in the view of security officials in many cases.