عنوان مقاله [English]
The rapid development of urbanization is one of the challenges for urban planners in the 21st century. Rapid urbanization in Iran with the influx of migrants to the cities without any effective program lead to development of informal settlements and marginal communities in cities, destruction of agricultural land and gardens, and extreme physical development.
In view of the marginalization due to land degradation around the city, the formation of unsustainable urban network, rising urban crime, increased urban poverty and expanding discordant town, make it essential to have manage the growth and physical development of the city. Researchers have led to developments outside the program to control, monitor and forecast models.
Urban modelling in the cellular space, first by the definition of the cellular geography in urban studies has compiled cellular automata and is a perfect tool for modeling the spatial dynamics. Despite the benefits of cellular automata model, this model also has its limitations to create a true urban dynamics, simulation and not powerful enough. Therefore, to fix limits of this model, it is required to combine it with used Markov chain model.
In this research, the Markov chain model and automated cells to simulate land use change process is used to evaluate the physical expansion of the city of Urmia between 1984 -2016 and to predict land use changes to year 1410.
To run the model, Satellite images of Landsat 5 and 7 and 8 in the years of 1984, 1992, 2002, 2012, 2016 of Urmia were prepared and then using ENVI software, IDRISI and ArcGIS, land use changes were calculated and finally the Markov chain model and automated cells were obtained.
Results and discussion
Urmia city due to very favorable natural substrate (highly desirable areas of agriculture and water resources) and the development of communication network and immigration in recent years has experienced rapid population growth. The rapid growth of unorganized settlement causes marginalization and ultimately converts the incorporation of surrounding land into the city, the settlements have been cooperative. An overview of the research (research overviews) carried out in conjunction with the physical growth of the city of Urmia shows the capabilities of satellite images and models existing in connection with this type of data for the evaluation of physical growth of the city.
n this research, use of satellite image information show that urban areas formed around the margins of the city in different time periods is one of the main factors of physical growth in the past decade. This form of growth and the expansion of the city caused the destruction of agricultural land and orchards of the region in particular. Urban area compared with other landuseshas expanded 5 times during this period. Garden and agricultural areas are declined in this period. The garden and agricultural lands around the city have decreased from 29.59 percent in 1984 to to 7.24 percent in 2016. During the period of nearly 32 years, half of bare lands around the city are converted into building environment. . In connection with the expansion of the city of Urmia, the surrounding settlements expanded in all directions. The city is mainly expanded in the South and South West and South East parts of the city. Given that the southern part of the city is mainly agricultural lands and gardens, this area has been changed into urban use. In the South-Eastern part the largest land use is bare lands for the city. A lot of Gardens and agricultural land of Urmia City are destroyed. It also reviews how the expansion of the city at this time indicated growth in the initial nucleus of the marginalization and the rural settlements around the city. The simulation results also show that until year 2030, urban built lands will increase to 7523.01 hectare (86.58 percent) according to master plan. The area of gardens and agricultural lands reduced to 619.60 hectares and arid lands to 546.33 hectares.
According to the tips listed in the city of Urmia, satellite imagery, maps and the results offered the following suggestions:
Due to the growth of the city and making indiscriminate opposition to the species of mushrooms and marginalization of the most recent period, it is necessary to monitor the municipality more accurate and more serious.
The physical development of the city update monitoring using satellite images with better separation for classification of land cover maps in the next research.
Due to being a dynamic process of land-use changes over time, it is recommended. In the meantime, the next research the use of dynamic models of physical and economic factors such as CA_Markov, social, and political factors, affecting the user changes, as well as comments to be considered.