Survey of spatial forms - physical city using quantitative modelscase study : sardroud city

 Considering that the population growth rate of the surrounding cities of Tabriz metropolis in 2006-2010 Sardroud, Ilkhichi, Osku, and Basmanj cities is 2, 1.8, 0.87 and 0.83, respectively, that the growth rate of Sardroud city is more than other all surrounding cities of the metropolis of Tabriz. The study of statistics related to Sardroud city shows the changes in population growth and stages of growth and development of the city so that the population has increased 2.6 times and the area of the city has increased 2.7 times during the 35 years (1976-2011).The increase of industries of Sardroud has played a significant role in the spatial-physical changes of Sardroud. By comparing the position of different economic sectors in Sardroud with East Azerbaijan province, the total growth rate of the reference economy in 1996-2006 has been equal to 1.6. Also, the province's economic structure during the mentioned period has always been negative and has had a downward trend. The variation rate of the economic structure in the province has been 3.126% in 1996-2006, in comparison with Sardroud city with a high variation coefficient of 7.164%.Population growth and increase in industries in Sardroud city have led to the 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 has been 6382180 square meters (65.2%) and, 3252635 square meters (26.35%) in 2011), and the emergence of various spatial-physical, environmental, social and economic problems, including land-use change, air pollution, water, soil, negative effects on green space, etc. Therefore, the current study can contribute to the logical understanding of these factors and recognizing the urban issues and problems, proper and rational dealing with these issues, and the thoughtful and tactical design for the future development of the city by recognizing and assessing the physical-spatial growth of the city in two periods of 1998 and 2012 and its changes over time.

The research method is adjusted based on the nature, subject, and objectives of each research. Therefore, the current study is comparative-analytical research and is applied- developmental in terms of nature. The information related to the area, etc. were collected from the master plan (provided by the Rajan Ab Zagros consultant engineers) and other researchers and is classified based on the research requirements. Relative quantitative entropy model, Gini coefficient. Moran, Gary, and adjusted Gary coefficients were used to analyze the data.

Based on investigating the density ratio of Sardroud neighborhoods in 2011, the entropy value of Sardroud was 0.91 in 2011. The entropy value in 1999 has been 0.85 for Sardroud neighborhoods. Although it has had more concentration compared with 2011, the entropy value has been towards zero. However, its value is high and indicates the sprawl in the neighborhoods of Sardroud city.The obtained Gini coefficient for 1999 and 2011 is 0.35 and 0.36, respectively, indicating the unequal distribution in two decades.However, the Gini coefficient value for 2011 shows the unequal dispersion of the population comparing to 1999. Moran coefficient was calculated for 1999 and 2011. The obtained value for 1999 is 0.03, indicating the unipolar random accumulation pattern of Sardroud similar to most of the cities in Iran. Also, the obtained value for 2011 was 0.01, indicating the movement of Sardroud towards being multipolar in the future. Gary coefficient was also calculated for 1999 and 2011. The obtained values for 1999 and 2011 are 0.05 and 1.99, respectively. It indicates that in 2011, the city was closer to the sprawl dispersion pattern and shows that accumulation and density in Sardroud were more in 1999, comparing to 2011, and the urban sprawl increases in 2011.
The calculations show that Sardroud city has been towards sprawl development, and this dispersion leads to the destruction of the agricultural lands and gardens.

According to the research findings, this type of urban structure has had many negative consequences in different environmental, social, and economic sectors, including destruction of the agricultural lands around the city and so on.  Taking efficient urban management policies to consider density, public transportation and land use that affect the urban form of Sardroud city. Since the city is inevitable to grow and expand and population growth is always present in cities, it is necessary to use specific strategies and tools to manage the growth of cities and effectively control the sprawl expansion of cities, to avoid further waste and destruction of suitable suburban agricultural land around the cities and reduce the negative consequences of this type of urban development.