分形视角下的陕北黄土高原沟壑区城乡居民点分布特征研究——以无定河流域为例

摘要/Abstract

摘要： 2015年12月召开的中央城市工作会议提出“在中西部地区培育发展一批城市群、区域性中心城市，让中西部地区广大群众在家门口也能分享城镇化成果”。黄土高原是我国水土流失最严重和生态环境最敏感的地区之一，地貌水系特征对其城镇化建设尤为重要。从黄土高原独特的分形地貌入手，以无定河流域为研究对象，探究城乡居民点与地貌水系的耦合关系。分形维数上，通过盒维数法测算出19处小流域沟道水系分形维数，并分析城乡居民点的数量、等级与沟道分形维数的内在联系。空间上，采取缓冲区分析居民点与沟道水系的临近关系并探究水系与居民点等级对应特征。研究发现：在数理分析上，（1）各小流域的分形维数越高，单位面积的居民点数量越多；沟道分形维数一定时，高等级居民点的出现会降低沟道内单位面积低级别居民点数量。（2）河谷沟道的分形维数达到1.223是沟道内出现县城的必要而不充分条件。在空间分析上，（3）城乡居民点分布与分形沟道水系相临近，并且居民点等级分布规律具有自相似性、层级迭代性。基于以上特征探索具有地域特色的镇村体系布局模式，以期为该地区城镇建设提供理论依据。

关键词: 黄土高原, 分形, 无定河流域, 城乡居民点, 村镇体系

Abstract: “A number of urban agglomerations and regional central cities should be established in in China's central and western regions,so that the people in the central and western regions can share the welfare of urbanization”, that is the spirit of the Central City Working Conference. The Loess Plateau is one of the areas where exist the worst soil erosion problems and the most serious ecological problems in China. So it is very important to study the characteristics of the landforms and the channel network for the urbanization in this area. The subject of the study is the Wuding River Basin in Loess Plateau area. Firstly,the fractal dimensions of nineteen small watersheds are calculated with box dimension method and least square method. The results prove that the landform of the river basin is a fractal form. The fractal features of hierarchy and self-similarity in regional geomorphology are also analyzed. This research further confirms CUI Lingzhou,LI Zhanbin,LEI Huizhu and other experts' judgment that the gully networks in Loess Plateau have the fractal characteristics. Nineteen small watersheds' fractal dimensions are generally distributed between 1.029-1.224. TheWuding River Basin landform is just in its infancy stage,so the soil erosion there is particularly bad. Secondly,there are 2 276 settlements in the Wuding River Basin. The number and grade of the settlements in each small watershed have been calculated. The internal relation between the number and grade of the settlements and the fractal dimension of the channel has been analyzed. Thirdly,buffer zone method is used to analyze the neighborhood relation between the rural settlements and the channel network system,so the corresponding characteristics of the water system and residential level have been discovered. The research shows three conclusions. In mathematical terms: (1)The higher the fractal dimension of each small watershed is,the bigger the number of the rural settlements in per unit area is. There are competitive relations among different grades of rural settlements. When the fractal dimension of channel is certain,the occurrence of high-grade settlements will reduce the number of the low-grade settlements in per unit areas of the small watershed. (2)Only when the valley channel develops to a certain level,can the high-grade settlements be found there. The fact that the fractal dimension of the valley channel reaches 1.223 is a necessary and insufficient condition for the county formation in gully: (3)The distribution of residential area is close to fractal channel network system,and the distribution law of residential grade has self-similarity and hierarchical iteration. Finally, this paper explores the layout model of town and village system which has regional characteristics based on the above conclusion. The layout of high-grade settlements is near the high-grade channel and the low-grade residential areas are located near the low-grade gullies. The channel water system and the flat valley land connect the residents of each grade.

Key words: Loess Plateau, fractal, Wuding River Basin, urban and rural settlements, village town system

中图分类号:

K901

吴冲, 张雯, 向远林, 田达睿. 分形视角下的陕北黄土高原沟壑区城乡居民点分布特征研究——以无定河流域为例[J]. 干旱区地理, 2017, 40(6): 1307-1316.

WU Chong, ZHANG Wen, XIANG Yuan-lin, TIAN Da-rui. Distribution of rural settlements in the Loess Plateau of Northern Shaanxi Province from the perspective of fractal theory:a case of the Wuding River Basin[J]. , 2017, 40(6): 1307-1316.

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