在构建城市影响力指数测度指标体系基础上,运用熵值法计算得出1988、2001及2012年长江经济带内110个地级市以上城市影响力指数;在ArcGis软件平台下,利用空间分析方法,依据改进场模型、扩散模型,综合测度了长江经济带内地级市以上城市的可达性、空间场能及扩散效应,并对其进行深入分析。结果表明:城市间影响力指数差异较大但整体呈缩小趋势,城市可达性水平基本呈现出"东部〉中部〉西部"的格局;区域内存在一条主轴、三大核心圈、多条辅轴的区域空间结构,构成区域"1+3+X"发展格局;长江经济带经过城市孕育、极核发展、点轴扩散、网络化、局域一体化发展5个阶段,基本形成串珠式核心-边缘结构,区域内出现同一时期多个阶段并存的现象。为加快长江经济带空间结构的优化重组,依据"以点布轴,以轴拓面"空间思想,进行结构要素优化,主要有:合理构建城市等级体系,培养地方增长极;科学规划交通网络,优化空间扩散轴线;合理优化区域分工与合作,构建多层级城市群。
Based on measurement index system of urban influence and entropy method,the urban influence index for 110prefecture-level cities in the Economic Belt of the Yangtze River in 1988,2001 and 2012has been calculated in this study.According to field model and diffusion effect model,further analysis on the urban influence index which comprehensively measure accessibility,spatial field and diffusion effect has been conducted with spatial analysis method and the aid of ArcGis.The result showed that:the urban influence index differed a lot but tent to be narrowing,the city accessibility moved mainly towards pattern of" East〉 Middle〉 West",and the urban differences had gradually narrowed due to the rapid development of expressway and high-speed railway.The Economic Belt of the Yangtze River has basically formed regional spatial structure with one main axis,three core cycle and multipleaxis supported,building an development pattern of" 1+3+X.The Economic Belt of the Yangtze River has gone through five phases,i.e.urban gestation,core development,pole-axis diffusion,networking,and local integrated development,mainly forming a beaded core-periphery structure and presenting multi-phrase in those regions at one time.In order to accelerate the optimization of spatial structure in The Economic Belt of the Yangtze River,structural elements will be optimized with the precondition of insistence in ecology and efficiency,the strengthen in reform and innovation of spatial management and the idea of"extending axis based on the point".The optimization of spatial diffusion axis will be performed under the rational urban level system,local growth pole and scientific transportation networking plan.Then,the goal of optimization of the Economic Belt of the Yangtze River will be fulfilled with the rational region distribution and cooperation and multi-level urban agglomeration construction.