Constrained ID3-CA Model Construction And Urban Expansion Research

With the economic development and population growth,the scale of China's cities will be further expanded,urbanization will enter a new stage of development.The problems such as inefficient land use,traffic congestion and farmland encroachment have become increasingly prominent in urban sprawl.Therefore,under the new urbanization situation,it is of great significance to construct the city model,simulate and analyze the urban expansion,to better plan the city layout,and to avoid the problems existing in the urban expansion in the past.Through the comparative analysis of existing urban models,two main problems need to be solved: one is that dig out valuable information from the past knowledge of urban expansion and learn from past experience;the other is that the time factor is injected into the expansion simulation.Aimed at the above problems,this paper constructs constrained ID3-CA model,the details are as follows:(1)In the process of data processing,a new data processing method is designed to solve the defect of the conventional data processing method of distance drive factor.The new method enriches the information contained in the cell which happened to transformation of land use in the past,highlights location characteristics of the cells.(2)By analyzing that the information gain of ID3 algorithm is 0,this paper improves conventional implementation of ID3 algorithm,and the fault tolerance of the algorithm is improved.And it provides technical support for the combination of new data processing method and ID3 algorithm.(3)The constraint of the constrained CA model is introduced into the ID3-CA model to prevent the spread of urban sprawl.In the implementation of the model,Drawing on the idea of dynamic neighborhood,the injection of time factors in the process of urban simulation is realized by updating the neighborhood of each iteration.That is dynamic simulation.The results show that dynamic simulation accuracy for construction land is 10% higher than static analog accuracy.(4)Compared with the traditional Logistic-CA model,dynamic simulation accuracy for construction land is 16% higher than the traditional model simulation accuracy.Therefore,this paper uses ID3-CA model to forecast the distribution of construction land in 2020,and analyzes the influence of important traffic lines on the urban expansion in the past.