Introduction
Spatial structure is the result of historical and physical processes and changing economic, social and political conditions. This structure is generally considered in two dimensions, population and employment, the first one describes the residence system and the second one describes the activity structure. The sudden and leaping increase in housing prices and, as a result, rents in Tehran has been an important factor for the reversal of the migration process. In fact, following the convergence of a huge number of immigrants towards Tehran and the excessive increase in the price of land and housing in another period of time, it has led to the divergence of the number of immigrants towards the city of Tehran and in contrast to the pathological attention to the surrounding space of this national city. According to previous studies in the analysis of the spatial structure of metropolitan areas, the impact of housing developments as a key factor in attracting and repelling the population has not received enough attention, so that in the analysis of the process of suburbanization and displacement, only the qualitative descriptions of housing are presented as an influencing factor; While to answer the research questions, methods that have taken on a spatial dimension have been used. Therefore, the current research aims to study the process of development and formation of the spatial structure of the metropolitan area of Tehran with regard to quantitative changes in housing prices in a morphological approach.The research method is descriptive-analytical according to the nature of the study. The nature of the methods used is the type of methods and analyzes of spatial statistics. The variables of population density and employment are used as dependent variables and distance from the center, distance from main roads and housing price are also used as independent variables. In order to measure the spatial analysis of population density and employment, kernel density tests, hot and cold clusters, and Moran's test were used. Then, to perform spatial statistics on the variables, standardization was first applied based on zero to one, and finally, geographic weighted regression (GWR) was used to measure the effects of independent variables on dependent variables.According to the regression of the spatial pattern of housing prices, it can be said that the level of housing price increases over time has an increasing role in the spatial distribution of the population, so that this number has reached 27% in 2015, from 23% in 2015, and it is an important contribution to the change The spatial structure of the metropolitan area will have. The density of employment tends towards the areas with low and medium average housing prices, and in terms of spatial distribution, the density of employed people in the metropolitan area of Tehran tends to the southern areas of the capital and the cities close to it. The independent variable of road distance infers 33% of the dependent variable of population density and is considered one of the important factors of population settlement in the spatial structure of the metropolitan area. The effect of the distance from the center has had an increasing effect on the population density, so that the distribution of the population compared to the distance from the center has increased from 18.8% in 1385 to 26.7% in 1395, and the cities and towns closer to Tehran have a greater increase in population compared to More distant regions have experienced.According to the R2 coefficient of the regression of housing price effects on population density, it can be said that the level of housing price increase over time has an increasing role in the spatial distribution of the population and has made an important contribution to changing the spatial structure of the metropolitan area of Tehran. Due to the rapid growth of housing prices in the recent period, the distribution of population and workers from the center has increased and tends to the areas with low housing prices, which spatially are large villages and close to urban centers, Mehr housing projects and new cities with relatively low prices. Housing compared to other residential centers will have the potential to attract more people. It seems that the trend of housing price developments in the long term will intensify the migration flows within the province and the pattern of the spatial structure of the metropolitan area of Tehran will undergo more spatial changes.

Keywords: spatial structure, Tehran metropolitan region, Changes in housing prices