Evaluation of the effects of the spatial - structural – form of the small towns fringing the metropolitan of Tabriz (case study :city sardroud)

 Introduction
The study of statistics related to Sardroud city shows the changes in population growth and the stages of growth and development of the city, so that the population during the 35-year period (1976-2011) has doubled and the area of ​​the city has doubled Increasing industries near Tabriz metropolis, which is located in Sardroud city, plays an important role in changes. As a result, population growth and industrial growth in Sardroud led to unplanned constructions and many changes in the spatial-physical structure of the city, the destruction of agricultural lands so that the area of ​​agricultural lands and gardens in 1999 was 6382180 square meters (65.2%) per year. 2011, 3252635 (26.35%) and the occurrence of various spatial-physical, environmental, social and economic problems in Sardroud city. Therefore, this study evaluated the spatial-physical effects of Tabriz metropolis on Sardroud city with the explanation that the factors affecting change The physical-spatial form of the city informs us of the logical understanding of these factors and of understanding the root of its problems. Each and every logical and correct confrontation with the problems as well as the thoughtful and thoughtful design of the future development of the city helped. Considering the above issues, the questions are as follows: - Has the proximity to Tabriz caused changes in the demographic structure of Sardroud city?- Has the spatial-physical developments of Sardroud city been affected by the expansion of industrial-workshop activities?
 Methodology
In the present study, the method of analytical-comparative research is the type of applied-developmental research. Relevant information from comprehensive study studies and other relevant sources are obtained and classified according to the research needs. Then, the statistical indicators of the research are extracted from the mentioned data based on statistical relations. Quantitative models have been used to analyze the information, which are as follows: Study and analysis of demographic changes using population estimates based on statistics of fertility rates and mortality in Sardroud city through people software, calculation of economic activity diversity index using From the Gibbs-Martin model, comparing the position of different economic sectors of the city with respect to the province using the share change model and the Izard model and measuring the physical-spatial form of the city using quantitative relative entropy models, Gini coefficient, Muran, Gary, and Gary adjustment.
 Results and discussion
In this study few models have been used. According to Bozhugarnia's diagram, the role of Sardroud city in 1996 was industrial, while in 2006-2011 it has taken on a commercial role. Comparing the position of different economic sectors of Sardroud city compared to East Azarbaijan province using the share change model, the growth rate of the total reference economy for 1996-2005 was equal to 1.6 and the economic structure of the province during this period has always been negative and declining. And the employment rate in agricultural sectors is -0.12, industry -0.04 and services are equal to 1.1; and by examining the changes in the economic sectors of Sardroud city based on the Izard model, the only service sector in the city compared to its similar coefficient in the level. The higher province is 252.6 against 137.3 percent, and the results obtained from the measurement of spatial-physical models indicate this. The form of the city is moving towards urban distribution and the values of the indicators in 1999 and 2011 are as follows: (relative entropy = 0.85, Gini = 0.35, Moran = 0.03, Gary = 0.05) And (relative entropy = 0.91, Gini = 0.36, Muran = 0.01, Gary = 1.99). Which has caused the destruction of agricultural lands and orchards, so that in the city of Sardroud in 1378 the share of orchards and agricultural lands was 65.2 and in 1390 it has reached 26.35%.
 Conclusion
Considering that Sardroud city has the most impact from Tabriz metropolis, the development of urban infrastructure of Sardroud city should be considered in line with Tabriz metropolis so that the lack of infrastructure does not lead to marginal growth and inappropriate spatial-physical changes. And in areas where marginalization has taken place, urban renewal and rehabilitation measures and empowerment measures should be taken. Examining the changes in the economic sectors of Sardroud city in the field of industry, private sector investment should be activated and private sector investment in various economic fields should be invested in government economic policies, increasing the amount of investment from city credits, equipping and further development of Shahid Rajaei industrial town. It depends on the carpet weaving and carpet industry in the city.The spatial-physical structure of the city of Sardroud is a pattern of urban dispersion. Due to the need to guide the development of the city towards greater sustainability, the need to change it and the use of strategies for greater compression of the city is felt.- In order to prevent inappropriate urban-physical spatial development towards vulnerable and ecological areas, it is necessary to mention suggestions for improving urban development. Due to the poor growth of the city and its builders, it is necessary for the municipality to exercise strict supervision according to the existing laws and regulations, or for a specific organization or unit to do so under the supervision of the governorates or municipalities.