基于GIS的丘陵山区小城镇扩展模式及其机制分析——以浙江省仙居县为例

A GIS Based Patterns and Dynamic Mechanisms of Small Town Land Use Spatial Expansion in Xianju County,Zhejiang Province

利用GIS空间分析技术,结合区域社会经济统计数据,对1981～2000年仙居县小城镇时空扩展模式和机制进行分析。结果表明,仙居县小城镇扩展有圈层式蔓延、带状和低密度蔓延等模式;其空间扩展是多种因素综合作用的结果,经济发展、人口增长、交通建设和自然地理环境对其扩展速度和方向都起着比较重要的作用;小城镇在不同时期,某种和几种因素的作用强度互不相同,从而产生不同的外部形态与小城镇空间扩展模式。

The land use maps of Xianju, Zhejiang Province in 1981, 1991, 1996 and airphotos in 1997 was used to study the spatial expansion of small town. First, The land use map in 1996 and airphoto in 1997 were updated to 2000 through field surveying. Second, the land use database was established. After database was established, overlay analysis techniques of GIS was carried out and area of small town in 1981, 1991, and 2000 were calculated. Also, the spatial differentiation maps of urban land use growth in Xianju during 1981～1991 and 1991～2000 were made. It was found that the small towns in Xianju expansion rapidly. During 1981～1991 the small town expanded 50%, and in Qiushan, even to 76.33%.The expansion speed slow down during 1991～2000. The spatial pattern of small town land use growth in Xianju include (1)concentric sprawl pattern, the new-added small-town land use were increased in distinct concentric zones. such as Chengguan, the center of government and economic, it expanded 52.09% surround the town zone during 1991～2000; (2)linear pattern, the new-added land use were increased along river or highway, such as Baita and Guanlu, and low-density sprawl pattern, The expansion were along the Linshi highway; and (3)low-density sprawl pattern, because of traffic inconvenience and industry underdeveloped, these small-towns take on a low-density sprawl pattern. the expansion speed was slow comparing with above pattern.During small-town expansion, a number of cultivated lands were destroyed and transformed to unrenewable construction land. In order to sustainable development, conservation of cultivated land should be taken into account.Dynamic mechanisms were analyzed using socioeconomic data. It is concluded that the rapid small-town resulted from the economic development and population increasement. In addition, the traffic construction and natural geographic environment are also contributed to the small-town expansion.