基于分形理论的长株潭城市群等级规模结构研究及对策

运用城市群等级规模结构分形理论和方法,对长株潭"3+5"城市群(以下简称"3+5"城市群)的等级规模结构进行了实证研究,通过测算几年来"3+5"城市群等级规模分布的分维值,得出结论:"3+5"城市群规模分布符合分形特征;模型拟合认为其人口、经济分布的分维值均大于1,表明"3+5"城市群等级规模结构集中,已处于发展的相对成熟阶段。为此在对这些特征做出解释的基础上,认为可从强化首位城市、加快长株潭一体化建设、提升次中心城市、重点发展中小城市、加快小城镇建设等方面着手对长株潭城市群等级规模结构进行优化。

RESEARCH AND COUNTERMEASURES ABOUT GRADING SCALE STRUCTURE OF CHANGSHA-ZHUZHOU-XIANGTAN CITY CLUSTER BASED ON THE FRACTAL THEORY

Hierarchical structure is one of the three structures in urban agglomerations,reflecting the variation of cities in scale as well as concentration or dispersion of the urban population,and it is of help for understanding the phase of urban agglomerations．The "3+5"city cluster is regarded as the trial zone of "the two-type society" of the country, it must be made bigger and more powerful, in order to realize enriching the people,building up the province and the scientific spanning development.This paper makes a demonstration about the grading scale structure of the Changsha-Zhuzhou-Xiangtan "3+5" City Cluster (here in after referred to as "3+5" City Cluster) in Hunan province with the use of fractal theories and methods．It is found that this region exhibits a city-size distribution following the rank-size rule．Based on the fractal theory, the anthors make an analysis on the size distribution of "3+5" City Cluster．Conclusions have been drawn by caculating dimensions of urban system over the past several years in "3+5"city cluster:"3+5"city cluster's scale distribution with fractal characteristics. This distribution seriously affects the exerting of radiariy action of the primate city. It could be concluded through the models that the grading scale structure of the city cluster is concentrated just in the more mature stage,since the fractal dimensions of the population and economic distribution is more than 1. Also, this article calculated that the 2, 4, 11 urban cities' index of "3+5"city cluster, showed some characteristics of the city cluster that the first distribution is not obvious, the urban primacy index is low, the scale effect is inevident,the urban scale is small in whole,the development of metropolis and big cities is not enough,medium-sized cities are prominent and the spatial distribution of cities is not equa1.To optimize its Grading Scale Structure, the following measures can be taken combine to: strengthen the main role of radiation in Changsha as the first city; to accelerate the integration of Changsha, Zhuzhou and Xiangtan,combining the three cities as one; to enhance the development of local characteristics and personalities of key cities; to focus on the development of small and medium-sized cities to avoid the distraction of fractal dimension; to speed up the construction of small towns and optimize the layout of cities and towns and other areas of Changsha, Zhuzhou and Xiangtan City Cluster; Taking these problems into consideration, this paper puts forward some detailed measures to improve this structure and realize the scales of a sustainable,rapid and sound development．