中国地级以上城市腹地的测度分析

一个明确而又合理的城市腹地范围,是保证一定区域内各城市实现合理功能整合的关键,也是对城市经济区进行各项研究的基础。通过构建衡量城市综合规模的指标体系,运用主成分分析法计算中国283个地级及以上城市的规模值。在GIS软件支持下,将中国划分为5km×5km的格网,利用场强模型,对2004年283个地级及以上城市的腹地进行了划分,比较腹地的范围及相互关系,并与省域和市域行政范围进行了叠合分析,实现了城市腹地测定、分析的可视化。结果表明:中国地级及以上城市规模值差异较大,最大和最小城市规模相差达284倍。场强值分布呈现明显的东、中、西递减的分异特征,与经济发展的梯度差异一致。中、东部的城市影响力的弱势区域全部分布在省域交界地带,在场强值大于12的级别上,东、中部城市的场强影响范围连成一片。各城市腹地范围相差亦较大,最大和最小城市腹地相差达5488倍。各城市在地理位置上不一定位于其腹地的几何中心,偏移比较大的城市往往成对分布。城市腹地与省域行政范围吻合度较差,根据腹地在市域行政范围内的面积比例,将城市分为4类,并提出相应的空间发展策略。依据腹地的分析结果将全国划分为3个一级城市经济区、11个二级区和38个三级区。

Measurements for Urban Hinterland Area of Cities at Prefecture Level or above in China

Hinterland supplies resources for the economic activities of central cities, so the range and the quality of hinterland are very important to city's development. However, the existing hinterland delimitation models are not enough to explain and analyze the complexities of urban system in China for their lack of maneuverability and their limit to only one indicator. In this paper, complex components for calculating the urban synthetical scale value are selected, with consideration to the following five specific aspects, i.e., population, economy, commerce, traffic and government capability, and the value is calculated by means of principal component analysis. Then, China is divided into 338828 grids, the scale of which is 5 km ×5 km, with the support of ArcGIS software. The field-strength of each grid influenced by cities at prefecture level or above in China can also be calculated. Meanwhile, each grid is allocated to exclusive city in the light of "maximal field-strength choosing" principle, and then, the hinterland area of 283 cities at prefecture level or above in 2004 in China can be delimitated automatically. Finally, the coherence and difference between hinterland area and administrative division are studied by overlaying these areas with province boundaries in order to provide scientific basis for adjustment of administrative division and delimitation of urban economic region. Results show that (1) the difference of urban hinterland cities was obvious among the cities at prefecture level or above in China, and the concrete facts show that hinterland area of the western cities is larger than that of the eastern ones, in which the maximum hinterland area is 5488 times of the minimum one. (2) The relationships between urban hinterlands are identified as four types: coexistence, inclusion, semi-inclusion and competition. (3) The coincidence degree between urban hinterland areas and their administrative division is lower. On the basis of measurement and analysis for urban hinterland, a three-level zoning project of urban economic regions of the whole country is put forward. According to the project, the first-level division includes North Region, Middle-and-east Region and South Region; the second-level division includes 11 regions, which are North China, Northeast China, East China, Shandong, Fujian, Central China, South China, Southwest China, Tibet, Northwest China and Xinjiang; and the third-level division is comprised of 38 districts, which are named after cities at provincial capital level or above. The measurement results also indicate that application of GIS spatial analysis methods to delimitate urban hinterland is convenient, precise and feasible, which can be an alternative approach of urban economic region division and urban system planning.