基于GIS技术的扬中市可达性定量研究——以过江通道的建设为例

A GIS-based Approach for the Quantitative Evaluation of Accessibility in Yangzhong——A Case Study of the Building of Taizhou Chang Jiang River in Yangzhong

可达性是指从一个地方到另一个地方的容易程度,目前主要运用距离度量法、拓扑度量法、重力度量法、累积机会法等传统度量方法,应用于人文地理学、区域与城市规划等相关研究领域当中。该研究以ArcGIS Desktop9.2平台为技术支撑,通过对影像数据、图形数据以及社会经济等属性数据进行整理来构建矢量数据库(geodata-base),运用GIS矢量和栅格数据的空间分析模块,采用时间成本加权距离方法,对扬中市过江通道建成前后的可达性变化进行了分析。该方法突破了传统的描述性研究,通过进行等时圈分析可以得到节点城市影响腹地的范围,并且可以精确统计出通勤覆盖范围的地域面积、人口规模和经济规模,为地区资源的合理配置提供更为科学的依据。

Accessibility denotes the ease with which activities may be reached from a given location using a particular transportation system. There is a number of accessibility measures： Time of access to city centre, mean travel costs, opportunity accessibility, economic or population potential. However, most of these measures lacked any social indicators about society equity. In this research, a quantitative method based on accessibility was put forward to improve the evaluation systems. The basic landscape data were obtained from satellite images, graph data, social and economy data, using geographic information system （GIS）. Based on the concept and principle of the accessibility, a cost weighted distance analysis（ in ＂Spatial Analyst＂ module of Arcmap）was conducted to analyze the changes of accessibility after the building of Taizhou Changjiang River in Yangzhong. Finally, the influences for the spatio-temporal change of accessibility were explained in detail. The results showed that the methods used in this research were able to evaluate the distribution pattern and rationality of urban resource.