Research On Urban Expansion Analysis And Scenario Simulation Of Yinchuan Plain

At present, the rate of urbanization has reached51.26%in2011, and the urban expansion is in a stage of high expansion, at the same time, a series of problems of urbanization appears with the rapid development of the economy and in the process of urbanization construction. The urban spatial growth is presenting a tendency of growing into an organic, open economic zone mania, such as Beijing, Shanghai. As a result, a serious of social and ecological problems appears, such as urban land resource configuration is not reasonable, scattered layout, traffic congestion, land reclamation from lake marshes. Yinchuan plain is located in the west of our country, has exposed many problems in the rapid urbanization process, bringing a serious challenge to the management and sustainable development.In addition, the urban agglomeration of the Yinchuan Plain which is one of the eight bolo urban agglomeration, is in the stage of development. So it’s very important to formulate reasonable strategy for urban spatial expansion, driving the economic development of the city along the yellow river and Ningxia. In order to provide certain scientific basis for the establishment of regional urban development plan, it’s necessary to predict the future urban spatial expansion.The primary aim of this research is to simulate future urban expansion of Yinchuan Plain exploring some scientific basis for urban development strategy based on four scenarios by making use of cellular automata methodology in the SLEUTH modeling platform. The four scenarios established from the aspects of ecology, planning and compact city were designed to simulate the spatial pattern of different urban conditions, considering the characteristics of the region and development strategy. The main research contents and results are as follows:(1) Using the maximum likelihood method to get the information of wetland (river, lake and so on) and5periods of urban data between1978and2011by remote sensing image. The characteristic of urban spatial expansion of Yinchuan Plain was analysed from the time and spatial scale in the last30years. The results showed that the urban area and expansion intensity is growing, and the city size of Yinchuan city is the largest, the speed of expansion intensity has increased since1999. (2)To get the input layers of SLEUTH model after data preprocessing, information extraction, and format conversion, by remote sensing and GIS technology, data is from remote sensing image, DEM, planning data. Different calibration methods were used to evaluate the rough calibration, and the results showed that the five indexes is the idea calibration methods. Then get the best predict growth coefficient value for this study area after rough calibration, fine calibration, final calibration and drive forecasting coefficients. Kapaa coefficient method and contrast analysis method were used to evaluate the prediction ability of the model, and the results showed that the prediction precision of the SLEUTH model was appropriate.(3)By altering the composition of SLEUTH input layers, four scenarios of urban spatial expansion in the future was generated, according to the regional characteristics, relevant development strategy, city planning and policy. The results showed that urban will expand in all directions and more farmland will be occupied for the maintain status quo; urban planning has a guiding role of urban development, the expansion is restrained; the local ecological such as river and lake will be protected in the scenarios of ecological sustainable development, but urban development will seriously limited if a total ban on surrounding farmland; Compact urban expansion plan ensures the urban agglomeration, urban spatial structure is more compact, and is more helpful for intensive utilization of land. Therefore, the government departments should formulate feasible urban development planning and management measures to guide the future urban space expansion, to control the wetland occupied by construction land strictly, and to reduce the waste of land resources by improving the land use intensity.