基于改进度的城市路网元素连接特性
Connectivity characteristics of urban road network elements based on improved degree

结合城市路网车道属性(数量、宽度与方向等)扩展了复杂网络中度的定义,分别研究了原始法和对偶法下城市路网中交叉口和道路元素的连接特性; 考虑实际路网与居民出行认知特性,将交叉口定义为节点,基于赋名道路法与类Stroke分析从居民认知角度界定道路元素,重点结合机动车道数改进原始度的概念; 在新的路网元素界定下,使用基于改进测度的平均最近邻度方法分析了交叉口与道路的连接特性,并考虑现有方法的不足,提出了连接系数的概念,更好地明确其连接关系; 以厦门市主城区为例对分析方法进行验证,分析了主城区路网连接特性。研究结果表明:该城市交叉口元素网络和道路元素网络皆为无标度网络,其幂指数分别为1.69、2.70; 路网元素的连接皆以某一节点为临界呈现分段特性,其中,基于改进度的连接系数邻界点取值分别为3.40、8.33; 道路元素的等级测度临界点取值为5,基于等级测度的连接系数临界点取值为3,从这一角度来看,城市路网并非简单的同配或异配网络; 提出的路网元素连接特性分析方法对城市路网拓扑特性的认识及路网演化模型的构建具有重要意义。
Combined with the lane properties(number, width, direction, etc.)of urban road network, the definition of degree in complex network was extended. The connectivity characteristics of road network elements including roads and intersections were analyzed by using primal and dual approaches respectively. Considering the features of real road network and resident trip cognition, intersections were regarded as nodes, and roads were determined by named street approach and stroke-like analysis from the perspective of resident cognition. The lane number of motor vehicle was emphasized to improve the concept of degree. Under the new definition of network elements, the connectivity characteristics of intersections and roads were analyzed by using the method of average nearest neighbors' degree based on the improved measures. Considering the deficiency of existing method, the concept of link coefficient was proposed so that a more clear connectivity characteristic was found. The main urban zone of Xiamen City was regarded as an example, the connectivity characteristics of road network were analyzed to validate the analysis method. Analysis result shows that the city's intersection and road element networks are both scale-free networks, and the power exponents are 1.69 and 2.70, respectively. The clear segmentation features are exhibited with the boundaries of particular points. Among them, the threshold values of link coefficients based on improved degree are 3.40 and 8.33, separately. The threshold value of hierarchical measure of roads is 5, and the threshold value of link coefficient based on the hierarchical measure is 3. From the point of view, it is shown that the urban road network is not simple assortative or disassortative network. The proposed analysis method of connectivity characteristics of urban network elements is of great significance for recognizing the topologic properties of urban road network and building network evolution model. 11 figs, 29 refs