Dynamic Mechanism Research On Xi'an Characteristics Of Urban Expansion In Time And Space,Space Differentiation And Its

City is the most important types of human settlement system,is the concentrated reflection of human social development,is also an important background of social economic development.After the industrial revolution,the world greatly accelerated the process of urbanization,the fundamental changes in the human life picture.Our country after reform and opening up,significantly speed up the process of urbanization,we are experiencing rapid urbanization process,on the one hand,to realize the rapid development of urban economy,urban space expanding,people enjoy a high quality of urban life at the same time,the city internal conflicts and contradictions gradually revealed,densely populated,traffic congestion,the outstanding problems such as wasting resources,these problems not only restrict the development of the city today,is not conducive to the sustainable development of city.Thus to reveal the objective law of urban expansion and analyze the characteristics of time and space,space differentiation phenomenon,in order to realize reasonable control the scale of urban land use and way,coordination between population,land,resources and economic development relationship has important practical significance.In this paper,the communist party of China(2004-2016,12 years 5 issue of the QuickBird remote sensing image as data sources,through from two aspects: general principles and specific rules establishing standards for remote sensing image interpretation,xi "an city extension information extraction,and then by mathematical method and the GIS spatial analysis method,from the urban expansion intensity,speed,compactness,center coordinates,transfer,extension mode,the space-time characteristics of urban expansion in the perspective of research from urban extension in the form of space differentiation and xi" an city function extension space differentiation two perspective in the process of extending the space differentiation phenomenon,finally combined with xi 'an city planning text and statistical data,on the basis of the analysis of the dynamic mechanism of urban expansion,expand the space differentiation respectively analyzed city form and city function extension space differentiation,so as to provide reference for city planning and management.Through this study,the main conclusions are as follows:(1)the extension of time process:From 2004-2016,xi 'an city always maintained extension rate is more than 10 km2 / year,extension strength is higher than 4% of the high-speed expansion stage,large area and expansion intensity and speed are the "hump" shaped,extension strength and speed reached peak in 2007-2010 period,but its strength of extension and speed of change law of xian can predict the future extension model will be made by the large area to rapid extension type large area;(2)the extension of space process: Extension center coordinates transfer: throughout xi 'an center migration path from 2004 to 2016,average annual migration linear distance of 285 meters,but look from the offset direction,center has a tendency to gradually to southwest migration.Extension of compactness: 12 years,xi 'an city of irregular shape,extension form belongs to a compact,urban space form is complicated.And expects the future a period of time,xi 'an city still irregular shape,compact degree is still not high,and the trend of the development of the city have to become more and more irregular shape.Extension mode: xi 'an urban spatial extension model is complex,characterized by a multitude of extension mode combination of the characteristics.Four patterns,the denotative and along the traffic line extension as the main extension mode,and in different periods of the construction of the city,the rest of the extended model role respectively different: in the early part of the urban construction,jump as the main extension mode,and in the city's development gradually stability and,in the process of urban renewal with the internal reform is given priority to with filling type.(3)the extension of city form space differentiation:2004-2016,xi 'an city form extended space differentiation,one of the biggest cities in the extension strength southwest,followed by south and north direction;(4)the city function extension of space differentiation:2004-2016,xi 'an city space differentiation function extension,show the overall function extension strength is not high,the city is higher than the north south,the general characteristics of the west is higher than the east,there shall area of high strength and low strength of the area,and the interval distribution,form the space differentiation pattern of xian city function extension.(5)the urban expansion and differentiation mechanism:Xi 'an urban expansion mainly by natural factors,transport factors,demographic factors,economic factors,development zone,the university factors as well as the urban village reconstruction,cultural relics and other factors.And among them,urban planning and development factor is the main cause of the extension of city form space differentiation,and the cause of urban function extension space differentiation,the extension of time,economic and development zone is probable factors,urban planning and functional zoning,population and traffic as well as the university city construction is the necessary factor.