可达性测算中速度参数的敏感性研究——以闽赣两省机场人口覆盖为例

Sensitivity analysis of speed parameter in time-based accessibility measurement:a case study of Fujian and Jiangxi Provinces

可达性是地理学重要的研究内容.在考虑时间距离的可达性测算过程中,道路速度的设置会对可达性测算结果产生影响,但目前关于道路速度设置对可达性测算结果影响的研究仍较缺乏.以福建和江西2省的机场可达性测算为例,采用机场1.5h内覆盖的人口数量来衡量机场可达性,比较不同道路速度设定情景下的可达性评价结果,从而考察道路速度设置对可达性测算的影响.结果显示:道路速度设定的不同所导致的机场覆盖人口比例差异显著,其中县道速度对覆盖人口比例的影响最大;不同速度设定下各机场覆盖人口数排名前五的机场没有发生变化,而排名后5位的机场发生了位次变化,对道路速度的敏感性较高.

Accessibility is an important indicator in the between nodes is required in such evaluation. One popular evaluation of transport network. The shortest time technique of GIS analysis is often used to calculate time cost by setting road speed according to road level. In this process, the settings of road speed may have significant influence on accessibility evaluation. Although this method has been applied widely in China, sensibility analysis of road speed impact on accessibility is seldom considered. In this paper, we investigated such effect in Fuiian and Jiangxi Provinces. Population within 1.5 h driving distance of an airport is defined as accessibility indicator. Accessibility evaluation is compared in 6 scenarios of different speed settings. The setting of speed is found to impact significantly on accessibility evaluation, both on absolute value of accessibility and on relative position of airport accessibility index. Relatively small values are especially affected more by speed setting. The speed on county road has a more powerful impact on accessibility value.