基于“点—轴系统”理论的城市群边界识别

Delineating the scope of urban agglomerations based upon the Pole-Axis theory

合理界定城市群的边界是认识和研究城市群的必然要求,也是通过空间规划落实区域功能空间布局和发展指向的基础条件。然而,社会各界对城市群的概念尚未达成统一的认识,对城市群空间范围的理解更是莫衷一是。为此,本文从经济地理学的"点—轴系统"理论出发,对城市群的概念进行了梳理,并提出判别城市群边界的4个步骤:一是分析对象区域是否存在若干发育良好的中心城市;二是分析这个区域的城市体系是否健全,是否具有较好的资源和环境条件;三是分析城市之间是否具有较强的社会经济联系,使之具有一体化发展的社会经济基础;四是通过对城市群实际生长边界的判别,对"点—轴系统"的发育程度进行评估,从而对该区域是否已经形成城市群进行判断。较之以往的学术研究,强调城市群的发育程度也应该作为城市群判别的重要条件,同时,也通过POI数据的Densi-Graph分析提出了判别城市群发育程度的方法。基于此,对京津冀及全国主要地区城市群的形成和发育进行了分析。结果表明,长三角城市群和珠三角城市群发展较为成熟,京津冀城市群一体化程度较之偏低,长江中游城市群和成渝城市群则尚处于形成阶段。这些结论对于客观认识城市群以及制定城市群未来发展的目标和战略具有重要意义,可为多层次的空间规划和管理政策提供参考。

Delineating the scope of urban agglomerations is a basic condition for understanding the evolution of cities and regions and for developing strategies and planning of urban agglomerations. At present, the scope of urban agglomerations in China are mainly decided based upon analyses of center cities and their connections with other cities by viewing them as separate points, but there is few consensus on how to define the spatial boundary of urban agglomerations other than using the jurisdiction border of the cities. In practice, there is a tendency to take urban agglomeration as a policy tool for raising the importance of certain areas and promoting regional development. As a result, the number and scope of urban agglomerations have been exaggerated. In order to solve these problems, in this article a methodology for delineating the scope of urban agglomerations is discussed from an economic geographic perspective based on the 'Pole- Axis Theory'. A four- step process was proposed:(1) to make judgment of the existence of central cities;(2) to examine the cities' rank system and the resources and environment base of the region to see if an urban agglomeration can be sustained;(3) to analyze the social and economic connections between central cities and other cities in the region;(4) to evaluate the development level of urban agglomerations with the scale of 'Pole-Axis Theory'. A case study is conducted in the Beijing-Tianjin-Hebei Region, and a comparison is made about the formation and development of the five main urban agglomerations in the Beijing- Tianjin- Hebei, Yangtze River Delta, Perl River Delta, Middle Yangtze River, and Chengdu-Chongqing regions.