Analysis Of City Spatial Expansion And Driving Force By GIS

Study on the expansion of the city is an important content of the new urbanization in the background, the development of the town, to promote the city space expansion research is particularly important, city spatial expansion of Mianyang city and the driving factors of the research in theory and practice to a small city in the future have important reference and guiding significance in the city expansion and land colleges and universities, intensive, sustainable use, and provide a new idea for the decision making of the local government on city construction.In this study, Fucheng district and Youxian district of Mianyang city as the study area, the study area in 1992, 2000, 2010 and 2013 four period and remote sensing images in 1992 and 2013 and the continuous data needs and research areas related to planning graph as the data source. Application of RS and GIS remote sensing data processing method, a difference of building coverage index(DBI=TM7-TM4) model, using the model to extract built-up land information. According to the area of information extraction, the quantitative and spatial characteristics analysis of city land expansion of Mianyang city and the analysis of the internal spatial structure of planning, and the driving factors of Mianyang city spatial expansion are analyzed in detail. Through the study, summed up the following conclusions:1) DBI index model to extract the urban built-up area of Mianyang city land use information extraction effect is an ideal selection, and the accuracy of information is more than 80%, meet the research needs.2) Area to extract built-up area and the data of Statistical Yearbook in the comparison of precision, the average precision of extraction of the area is 86.7%, the average error is 13.3%,and can be used for the city space expansion research.3) Mianyang city spatial expansion, expansion intensity is from strong to weak in 1992-2013 period.4) The study area city use of construction land increasingly compact, at the same time, the city built-up area of construction land is still in the continued expansion of the state.5) Built-up area of Mianyang city in the eight directions is spatial difference.6) Mianyang city spatial expansion is the result of joint action of natural environment, city traffic,economy, population, city and fixed asset investment and policy orientation,and economic is one of the most prominent factors.