On Extraction and Fractal of Urban and Rural Residential Spatial Patten from Yanggong River Drainage Area in Yunnan Province
云南漾弓江流域城乡聚落形态信息提取与分形分析

Yanggong River is a tiny anabranch of upper reaches of the Changjiang River. Its drainage are consists of Lijiang basin and Heqing basin,and is a representative area in northwest Yungui Plateau. Furthermore,there are differeat natiouality and culture background between the upper basin and the lower. Before late 1990s,urbanization process in Yanggong River drainage area is spontaneous,after then,it has been quickened,especially the county seat of Lijiang and Heqing. Spatial pattern of urban and rural residential area has changed greatly, which was reflected mainly in spatial diffusion. With the changes,the problem of how can we realize sustainable development of urban and rural residential area in scale,form,pattern and function in a certain spatial and temporal range shonld be paid attention to. The paper explores the method to extract urban and rural residential information of research area by remote sensing technology,using imitated ratio of vegetation index(RVI)to extract the spatial information from the Landsat TM images of 1996's and 1999's,measuring fractal dimensions to explain urban and rural residential area complexity and stability with time out,and comparing the pattern characteristics of the two county seat cities. According to the bigger residential fractal dimension value of total residential area in 1999 than 1996's and the contrary result while excluding the county seat of Lijiang and Heqing,we find that the Lijiang city and Heqing city become more complex and unstable from year 1996 to 1999 ,but the pattern changes of rural residential area is different. Although the changes of residential area pattern are caused by many factors that interact with each other,the function of various factors is different. We study the dynamic mechanism for facilitating the pattern of the residential area on the bases of research pattern,and find that the earthquake happened in February,1996 and opening of the highway from Dali to Lijiang passing through Songgui basin in 1998 are primary factors influencing the Lijiang and Heqing city and rural residential area along the road. And the flourishing tourism is also important,which leads to the different change rate between Lijiang and Heqing in past three years.