Research On Construction Land Expansion Based On GIS And RS In Guangzhou For Nearly 20 Years

The past 20 years, the urbanization development is in a rapidly period in Guangzhou,the built-up land expansion will be the main features in LUCC, and it will being increased, the agricultural land will be reduced, however, the land resources is limited. Thus study on dynamic change in urban built-up land and its driving factor, while planning to build the built-up land reasonable, making the social and ecological sustainable development of the fundamental objectives.In this paper, with the date source based on the TM remote images in 1990, 1995, 2002 and 2008 of Guangzhou, NDBI and comprehensive index method were used for the expansion of built-up land. Study of built-up land expansion from several points: I.Urban expansion intensity; II.Urban space complexity and stability; III.The direction of urban expansion; IV.its driving factor. The conclusions as follow:I. Using NDBI, comprehensive index method,comprehensive index method and supervised classification extraction method to extract the built-up land on TM image,the result shows that comprehensive index method and supervised classification extraction method is the best.II. For nearly 20 years, it is a high speed and will being increased in expand the area of built-up land in Guangzhou City: Firstly, the urbanization of Guangzhou City, Panyu and Huadu District, were higher than Conghua, and Zengcheng, while the rate of built-up land development were also higher. Secondly, the urban land use is expaning rapidly in year 1995~2002. Finaly, the expansion of built-up land is expanding as Concentric circles in 1990, expansion of the distribution ring is more concentrated.III. The expansion of built-up land area is 867.34 km2 from year 1990 to year 2008 in Guangzhou, accounting for the proportion of total area total area increased from 5.49% up to 17.16%,the proportion of built-up land area increased by 32%, the average annual expansion area is 48.1km2, the average annual expansion intensity is 0.65%. Overall, average annual growth rate and the average annual expansion intensity continue to decrease for nearly 20 years.IV. From year 1990 to year 2008, the fractal dimension of built-up land shows a decreasing trend in Guangzhou City. The stability of built-up land is better.(1)1990~1995, the fractal dimension and the stability of built-up land is be increasing.1995~2008, the fractal dimension showing a decreasing trend, the stability get stable with time.(2) Guangzhou City is the largest in the fractal dimension, Showing the highest degree of urbanization, the most complex form of built-up land. Panyu District is the smallest in the average fractal dimension.V. The rate of urban centroid in built-up land is the fastest between 1995 and 2002, the urban centroid is relatively stable from 2002 to 2008. The urban development plan is main reasons for the migration of built-up land.VI.Socio-economic development and population growth in urban built-up land expansion is the main driving factors in the factor analysis.on the one hand, Socio-economic development is the most fundamental drivers, The population growth is the most direct factors.