Analyzing the Mechanism of Land Use Change in Beijing City from 1990 to 2000

The objective of this study is to ascertain the temporal and spatial differences of land use conversion in Beijing.Land use status and land use change information in the year of 1990,1995 and 2000 were extracted by integrating TM images with Remote sense software.We use historical meteorological data,hydrological data and other spatial data to make an in-depth analysis of the changing characteristic based on statistic method in conjunction with GIS,and driving force of land use in Beijing city.This paper illustrates the spatial expansion process and mechanism of urban land utilization through the principal conversion type analysis in 1990s with spatial center of gravity transfer model and fractal model.The more detailed results include: firstly,the main characteristics of the city's land use change are the obvious reduction of the existing farm and the expansion of urban land use along several major roads.The spatial analysis of land use of Beijing shown that the even change rate of land use reached 0.95%. The urban land use grew to(220 131) hm~2 from(147 000 hm~2,) an annual average increase rate of 5.28%.The farm land use decreased from(585 270 hm~2) to(491 521 hm~2,) an annual average decrease rate of 1.60%.Secondly,the direction of gravity transfer of Beijing urban land use is northwest from 1990 to 1995,and southeast from 1995 to 2000.Third,the fractal dimension in different periods is calculated based on the features of different county.The results of analysis suggest that spatial structure of urban land feature in Beijing is obviously fractured.If D1.5,the shape of the urban system is more complex and is in expansion stage.If D1.5,the shape is becoming more simple.According to the results of the calculation,the fractal dimension of spatial structure is 1.74378 in 1990,which implies that urban system is in extension stage.With the evolution of urban system,from 1990 to 1995 to 2000,the increased urban area is evenly filled the city,and the D value is decreased from 1.74378 to 1.58778 to 1.27981.Lastly,the development of economy can better explain the expansion of urban land use than urban population with the partial correlation analysis.The external driving forces of expansion of urban land use in Beijing are the rapid growth of urban population and foreign investment.The basic forces of expansion are the transportation issue,topography,land patterns and the policy of government.