城市交通网络形态特征分形计量研究

The Study of Fractal Approach to Measure Urban Rail Transit Network Morphology

从城市形态结构“增生和替代”的变化方式和城市形态“向外扩展”和“内部重组”的双重演变过程,阐述了城市形态和城市交通网络形态的互动滋长演变关系及其形态相似性;本文首次明确提出了城市交通网络形态计量问题,并根据分形几何学的基本原理,提出了容量维数、覆盖维数、阻抗维数和分枝维数四个分形维数指标,分别对交通网络的容量水平、出行服务覆盖状况、网络整体可达性及网络结构的复杂程度及其变化特征进行数学描述,建立了交通网络特征的分形计量方法.通过对北京、墨西哥和莫斯科三城市轨交网络的测算表明,该方法能够较好地刻画不同形态类型交通网络的主要形态特征.

This paper described the interactive growth relationships and morphological similarities between urban morphology and urban transport networks morphology. From the view of ＂increase and replacement＂ mode of urban morphology structure and the interactive process of ＂urban sprawl and inter reconstruction＂ of urban morphology, The paper brings forth the method to measure urban rail transit network morphology and, by adopting fractal geometry＇s principles, builds four fractal dimensions： traffic capacity dimension, passenger coverage dimension, resistant dimension and branch dimension to mathematically portray traffic network capacity level, trip service coverage status, traffic network connectivity and their varieties. A fraetal measure method of urban transit rail networks morphology is established. The measurement to rail transit networks of Beijing, Mexico and Moscow has indicated that the method can character the main fractal features of different rail transit network form preferably.