Study On Urban Three-dimensional Expansion Based On GIS And CA

The urban problems become much complicated with the rapid progress of urbanization,and have a profound impact on society,economy and environment.Along with the rapid economic development and urban land resource limitation,the horizontal space of urban expansion is getting much smaller and the trend of vertically upward expansion become much obvious.Through the research of characteristics of urban three-dimensional expansion,explore its mechanism and simulate land use change,multi-source and multi-timing geospatial data combined with GIS and CA technology,based on the urban three-dimensional system as the research object,so that we can master the law of urban spatial expansion from the whole and provide decision-making support for urban planning and development at a certain extent.It has very important significance for understanding the agglomeration and diffusion of demographic and economic,and achieve sustainable urban development.Taking Zhongshan district of Dalian city as an example,through the above research the major conclusions are:(1)The characteristics of urban three-dimensional expansion of Zhongshan district are obvious,the characteristics are mainly as:①The high-rise buildings maintain a rapid growth,the largest number growth are small high-rise buildings,the largest proportion growth are high-rise buildings and super high-rise buildings;different types and heights of buildings show aggregate distribution and present significant positive spatial correlation.② The fluctuation of urban skyline in Zhongshan district is obvious,showing a state of "west-high and east-low" and "north-high and south-low",and super high-rise building aggregation appears in northwestern.③ There has an obvious difference both with floor area ratio(FAR)of land parcel and building density on the spatial distribution,the land parcel with low FAR is reducing and increasing with high,and the greater the FAR of land parcel exhibit continues to increase.(2)A local land use competition cellular automata(LLUC-CA)model is built and simulated land use change in Zhongshan district,the result proved that the model has a good simulation accuracy by comparing the Kappa Index of Agreement with the simulated land use map by LLUC-CA model and the actual land use map,as well as comparison with traditional CA-Markov model.(3)The pattern of urban three-dimensional expansion of Zhongshan district in current time is mainly "endogenous" type,and belongs to the highest stage of the development of urbanization.The possibility of two-dimensional expansion is getting much smaller,the building floors and construction density will continue increase,the development intensity of three-dimensional space will be further enhanced,and urban expansion will grow into the third dimensional direction,driven by natural conditions,traffic connections,urban planning and development strategy,and the evolution of industrial structure and industrial agglomeration.