广州市地铁可达性时空演化及其对公交可达性的影响

应用GIS方法,选取2000、2003、2009和2012年4个时间节点,运用复杂网络理论构建了广州市公共交通网络模型,通过对比分析地铁站点与线路加入到公共交通网络中所产生的变化,定量分析地铁网络建设对公共交通可达性的影响,分析地铁发展不同时期内,城市公共交通可达性空间格局的演化,全面探讨地铁建设对城市公共交通可达性的影响,以期为一体化的多模式城市公共交通体系发展决策提供理论支持。结果显示:①广州市地铁网络顺利完成由树状向回路网络的转变,地铁可达性重心与广州市空间扩展方向呼应,呈现出向南、向东迁移特征;②地铁在很大程度上提高了广州城市公交网络可达性,且其改善作用随地铁线路网的增加和回路网络的发育而日益显著;③地铁网络对城市公交可达性格局的影响,打破了常规公交网络圈层式公交可达性格局,逐渐呈现出圈层式加沿地铁线路分布的廊道式格局;④地铁对公交各站点网络可达时间的影响,常规公交站点可达时间变化程度呈现出由地铁线路向外递减的空间分布趋势,当地铁网络发育形成回路网络时,大大地提升公交网络的运营效率,缩短各个站点之间的出行时间。

Spatial-temporal evolution of Guangzhou subway accessibility and its effects on the accessibility of public transportation services

Investigating effects of subway on urban public transportation network and accessibility is important because it contributes to sound planning of subway systems, improving urban public transport service accessibility, and providing possibility for the transformation of individual travel modes. This research uses the theories and methods of accessibility study to explore the relationship between the development of urban rail system and bus services, taking Guangzhou as an example. The study focuses on the status of public transportation system in four years (2000, 2003, 2009 and 2012). Data used in this study cover the stations and networks of buses and subways that come from our digital processing with GIS. Using published maps and Internet data as sources, this study established a database of public transport in different years. It uses complex network theory to establish the model of public transportation network in Guangzhou and quantitatively analyses the influence of urban rail system on bus accessibility through a comparison of the urban transportation network that incorporates urban rail system and the bus network that did not include urban rail system. The evolution of the spatial pattern of public transportation accessibility in different time periods is also discussed. Subway accessibility analysis is based on subway station and network accessibility and the change in center of high accessibility is analyzed to represent network accessibility change over time. The purpose of this study is to provide theoretical support for an integrated development of urban public transportation system through the analysis of the comprehensive influence of subway construction on urban public transportation. The principal findings of this study are as follows: (1) The Guangzhou subway network successfully completed the transformation from the tree-shaped to the loop network. The high accessibility center of the Guangzhou subway network moved to the east and south and this is consistent with the direction of the city's spatial expansion. (2) The incorporation of the urban rail system did have impacts on the overall accessibility of the public transportation network. (3) The subway network influences the spatial pattern of Guangzhou public transport accessibility. Along the metro line public transport accessibility is better than other regions. (4) Through the comparison of accessibility over years, we found that urban subway network expands residents' travel range and shorten travel time at the same time. As urban rail network continues to expand, public transport accessibility will steadily improve along the subway lines. This study only discusses transportation infrastructure-the subway and bus networks. Travel demand of city residents is not considered in this study. Future research can examine the coordination of the subway network and urban public transportation network and explore demand and supply of subway and bus networks by taking into account the distribution of resident travel demands..