基于陆路交通网的区域可达性评价——以长江三角洲为例

对于给定的区域而言，区内任意一点可达性的评价应当是区内可达性和区外可达性的综合评价。利用MapX控件和Delphi编程工具，开发了基于时间最短的区域可达性计算与分析信息系统，生成了可达性的分值扩散图。基于长江三角洲的陆路交通网，从时间距离的角度对长江三角洲内16个地级市目前和未来的区内可达性和区外可达性进行了评价。结果表明，长江三角洲区域可达性呈现出以上海为中心的扇状辐射，可达性最好的是上海和嘉兴，可达性最差的是台州和南通。随着苏通大桥、杭州湾跨海大桥和舟山大陆连岛工程的建成，长江三角洲地区内所有城市的区内可达性都有了提高，尤其是绍兴、宁波和泰州，区内可达性减少了1h，其余城市区内可达性平均减少了25 min。随着南通洋口港的建成，长江三角洲境内江苏城市以海港为节点的区外可达性都有不同程度的提高，到达海港的平均时间减少了近1h。

Assessment on Regional Accessibility Based on Land Transportation Network:A Case Study of the Yangtze River Delta

For a given region, internal accessibility and external accessibility should be considered to assess accessibility of each point in the region. Using MapX component and Delphi programming tool, regional accessibility calculation and analysis information system based on minimal pass-time is developed, with which mark diffusing figure could be generated. From the view of time-distance, the present and approaching regional internal accessibility and regional external accessibility of 16 major cities in the Yangtze River Delta are analyzed according to land traffic network. The result shows that, the regional accessibility of the Yangtze River Delta radiates a fan-shaped pattern with Shanghai as the core. The top two cities are Shanghai and Jiaxing. The bottom two cities are Taizhou and Nantong. With the completion of Sutong Bridge, Hangzhouwan Bridge and Zhoushan Bridge, the regional internal accessibility of all cities in the Yangtze River Delta will be improved. Especially for Shaoxing, Ningho and Taizhou, the regional internal accessibility will be one hour decrease. At the same time, the regional internal accessibility of other cities will be about 25 minutes decrease averagely. As the accomplishment of the Yangkou seaport in Nantong, regional external accessibility with the node of seaport of cities in Jiangsu province will be increased with an average decrease in accessibility by about one hour.