Urban Simulation Based On GA And Landscape Pattern Evaluation

With the rapid development of China’s urbanization,urban and rural construction land expansion.In order to avoid the "urban disease" in the process of urbanization,simulation of urban land use dynamic is of great significance in order to predict the future urban structure and evaluate it.Simulation of urban land use dynamic can qualitatively and quantitatively study the mechanism of land use change(Land Use/Land Cover Change,LUCC)in urban system.The model of urban land use dynamic can simulate the process of urban dynamic expansion effectively and predict the distribution and pattern of urban land in the future.How to improve the accuracy of the urban model based on geographic cellular automata has been the direction of academic efforts.Aiming at the deficiency of the conventional logistic regression model,the GA-logistic regression model is constructed,and the dynamic change of the urban land is simulated as an example of the Chengdu Chongqing Economic Zone.In other words,the genetic algorithm is used to fit and obtain the best regression coefficient of logistic regression model to optimize the dynamic model of urban land use.The results show that the urban land accuracy of logistic regression simulation model based on genetic algorithm is increased from 78% to 85.3%,and the overall kappa index is increased from 74.5% to 81.2%,which is respectively improved by 7.3% and 6.7%.Research shows that logistic regression parameter optimization method based on genetic algorithm has a better simulation effect than the conventional logistic regression methods and more suitable for a large range of urban land dynamic simulation of unbalanced data,more features’ data etc.In addition,the model is applied to the simulation of the future urban of Chengdu Chongqing Economic zone.The results show that the maximum patch index,aggregation index and area weighted mean fractal dimension index are rising with urban development,and the patch density index is falling.The results show that the urban agglomeration of the Chengdu Chongqing Economic Zone develops along the large and medium-sized cities,and the large and medium-sized cities have a strong ability of centralized allocation of resources,as well as the strong radiation capacity of the surrounding counties.