Design of Optimal Horizontal Urban Growth Model (Case Study: Yasuj)

Expanding cities is unavoidable, and this growth becomes problematic when the expansion process is spontaneous. As a result, urban development monitoring, analysis and forecasting planning has been considered. The purpose of this study is to develop the city of Yasuj using a GIS-based cellular automata model to evaluate urban horizontal development by 1410. At first, physical fitness parameters, communication paths and neighborhood effect were calculated. Then, according to the demand of different land uses, the developed and undeveloped areas were identified. In the next step, the allocation of demand-side land uses has been made using the interaction between demand and the overall proportion of each real estate and proportional to the maximum value obtained among the land-use maps. The results showed that the proposed modeling increases the development of Yasuj city from its outer radius and especially from the southwest area, because the natural obstacles in the north and east of the city prevent its expansion. Cellular automata modeling evaluation indicates 61% accuracy for horizontal growth. In general, the results of this study can be a reference for future urban planning.         Extended Abstract       Human civilization is currently entering the urban century (Korit et al., 2014). Urban areas are experiencing rapid growth, mainly as a result of population growth, rising incomes, and declining travel costs (Brochner and Larji, 2008), especially in developing countries, as cities grow rapidly and the number Metropolises have increased significantly. According to the United Nations in 2014, 54% of the world's population is urban. That number was about 30 percent in 1950. In 2050, it is projected to reach 66 percent, making population control and urban area a major challenge (World Urbanization Prospects, 2014). Also, according to the census of the Statistics Center of Iran in 2016, 74% of the population is urban, while the growth in 1390 was equal to 71.4% and the urban population in 2016 compared to 1390 has grown by 2.6% (center) Statistics of Iran, 2016). The city of Yasuj is an immigrant city due to its low urbanization history and being located as a political, administrative and service center and favorable weather conditions, and it is facing a large increase in population every year. So, this city is moving towards development and growth, willingly or unwillingly. In recent years, the development of the city of Yasuj is one of the most important proposals on the agenda of the authorities.        In this article, we seek to answer the question of how modeling urban space patterns can provide a good view of the development of cities under different social, economic and environmental conditions. Therefore, the purpose of this article is the horizontal development of Yasuj city with GIS-based cellular automatic model. By the way, it is adjacent to developed urban areas. Some areas such as green spaces, gardens, military areas and zoos are not expandable.       Steps must be taken in modeling the horizontal development of the city using the cell automation model. In the first phase of the study, the overall fit of the undeveloped parts with the parameters of the physical fitness factors, access to the transport infrastructure, and the neighborhood effect were calculated. In the next step, the allocation of demand-driven applications is done using the interaction between demand and the overall fit of each property and in proportion to the maximum value obtained among the fitness maps. Using physical fitness factors, access to transportation infrastructure and neighborhood effects, overall fit of underdeveloped parts was calculated and a separate map of each factor was prepared. Finally, according to statistical relationships, they are combined using multi-criteria evaluation method.       Criteria for urban growth and development of these cells are the result of a combination of environmental and environmental criteria (slope, land capability) and physical (distance from the communication network and land use). Combining these criteria using the raster model creates 3 modes suitable for development, somewhat suitable and unsuitable for development for cells. Therefore, 6 features are expressed for cells, including: urban development, rural development, communication network, suitable for development, somewhat suitable, unsuitable for development. In order to calculate the neighborhood effect, all neighboring parts of the desired piece up to a radius of 700 meters (Optimal radius) Selected and tailored to the type of use and level of service (neighborhood, district and region), the interactions of the target user and the neighboring user are extracted in three categories of adaptation, dependence and centralization and based on the distance and area of ​​use. Neighbor to the target property piece, the final score of compatibility, dependency and centralization was calculated. Finally, after standardization and application of the weight of expertise, they were combined. In this section, the cellular automatic model with the characteristics specified in the study area was simulated in 10 two-year time periods on the data of 1390 and the future growth path of Yasuj city until 1410. The area of the city extends from the outer areas of its radius, especially from the southwestern part, because in the north and east of the city, natural barriers have prevented its expansion. The inner development of the city has occurred to a small extent in the northeastern parts. But an important part of the future growth of Yasuj city has taken place in the form of development outside the area and in the southwest.        The city of Yasuj expanded in three axes during 1986-1995, and as a result, a large number of neighboring villages merged with the city. Yasuj is an immigrant city due to its low urbanization history and being located as a political, administrative and service center and favorable weather conditions, and it is facing a large increase in population every year. Therefore, in this study, the horizontal development of Yasuj city was investigated using cellular automatic model. The results of modeling the development of Yasuj city using cellular automata showed that the city increases its radius from the outer areas and especially from the southwestern area, because in the north and east of the city, natural obstacles prevent its expansion. It can help urban planners and decision makers understand the implications of their decisions about urban growth and development. Urban planners also use dynamic systems to control urban growth, given that the factors influencing the formation and change of cities change over time and even vary from city to city and from region to region. , It is suggested that in future studies, different parts of the city be considered to find the optimal parameters of cellular automation. Also, in this article, cellular automata have been used to model the horizontal development of Yasuj city. Therefore, in the next step, the mentioned model can be used to model the vertical growth of Yasuj city.