Evaluation and Prediction of the Optimal Path for Urban Development of Sanandaj Using CA Markov

Introduction
We consider the city as a dynamic system, this system will develop physically as a result of internal and external changes which can be effective factors in urban development. The physical development of the cities is interpreted as the model of physical development. As we need appropriate planning and management, urban planners have persuaded to combine temporal and spatial information to detect suitable developmental and predictive models. Therefore, optimal planning and site selection for different directions of spatial development are important for the future expansion of cities. Sanandaj is located in the northwestern Iran as the capital of Kurdistan province. The population of Sanandaj was changed a lot during the four decades due to immigration and its centrality. Its population was 95870 in 1976 which increased to 204384 in 1986 and experienced the growth of 7.8%. Although its rate decreased in the next two decades, it has been an important target for immigrants and its population was 375280 in 2011.
Methodology
Like the other cities of Iran, the physical development of Sanandaj has experienced great changes during the recent decades. These changes have been purposeless both in rate and in direction of development. Population change after the Islamic revolution has caused to an increase in physical textures of cities as well as the physical changes of the villages. These changes have changed Sanandaj so that it is now one of the cities in Iran where has a high proportion of informal settlement and the nearby villages have had extreme changes in their function. Immigration, national centralization and so on are among the main reasons of this disintegration. The main purpose of this study is data based modeling by spatial and temporal information using GIS and RS. Urban development simulation in urban and nonurban areas was conducted by employing CA-Markov model to determine the optimal path of development. Infill development of urban areas and using internal potential are among the outstanding criteria. This kind of development uses the inside areas of the territories not surrounding for the purpose of redevelopment. This development causes both economizing in using lands and optimal using of infrastructures. It also causes using barren land like development in brownfields which, in turn, leads to the economic use of urban lands and the promotion of neighborhood social and physical qualities.
 
Results and Discussion
In this study, the researchers used a combination of automatic cells models of Markov chaining and logistic regression for the simulation and prediction of the development of the city. Based on the data gathered 1998 and 2006 and satellite photos, the researchers simulated the development of the city for 2022. They have predicted the development based on Markov model and other factors like farming lands. The results of the study show that in the simulation of the current development of Sanandaj up to 2014, more barren and mountainous land (655 hectares) have been changed into urban lands. For prediction of the required lands of sprawl development, infill development was the first choice and then the outskirt lands were taken into consideration. In this study 1. urban old textures; 2. urban unsuitable lands (Brownfield); 3. barren lands of Sanandaj are the main choices of infill development. Based on the last amendment of old texture map in 2014, Sanandaj has got 689.5 hectares of old texture. It has been divided into the historic old texture (central) archaic old texture which has no historic value (middle) and marginal old texture (informal settlement). The area of barren lands for infill development is 791 hectares which include the considerable bulk of sprawl development in Sanandaj. Brownfield lands are not adaptable to the nature of city and urban life. For an optimal interaction and adaptability among urban activities based on the law of the great council of Iran architecture, people should go out from the city territory. The limitation of unsuitable lands of Sanandaj was in 159.4 hectares. In accordance with the data of 2006 and 2014 and the CA-Markov simulation model, internal and sprawl development of Sanandaj has been predicted. Accordingly, 62.6 hectares of the lands with planned cover, 998.8 hectares of barren and mountainous lands will changed into urban territory in 2022.  
Conclusion
Since this area is mountainous and there are a lot of barren lands in urban territory, more barren and mountainous lands have changed into urban areas. It is predicted that the urban territory of Sanandaj will be 5154 hectares in 2022. In fact, b with the required law and applying restriction map, about 329 hectares of old texture lands have been taken into account for urban development and consequently this number of farming lands cannot join to urban territory. By giving priority to the barren lands inside the city in restriction map, the changes of lands has been prevented. It is predicted that most of the sprawl development has been in northwest and south west. In 2022, urban and mountainous lands will change into urban lands to a large degree. Based on the results of the study, Markov automatic-chaining cells model has a high productivity in urban development and prediction.