层次性是道路网一个重要的空间结构特征,文中提出一种城市道路网面域层次结构特征的识别与表达方法。首先以路链为基本单元对道路网数据进行重新组织,选取连通度、接近度、中介度和长度对路链的结构特征重要性进行评价;然后以道路网眼作为表达道路网面域层次结构特征的基本单元,依据路链的属性等级、结构特征重要性以及视觉对称性原则,依次选取路链对道路网最大包络区域进行层次剖分从而获得其包含的各级层次道路网眼;最后利用二叉树模型对道路网眼之间的层次关系和邻接关系进行结构化表达。实验结果表明,所提方法能够完整提取出道路网包含的全部道路网眼并准确建立它们之间的空间关系,其结果能较好地反映道路网面域的层次结构特征。
Hierarchy is an important spatial structure characteristic of road network. An recognition and expression method for areal hierarchy of urban road networks was proposed. Firstly, road network data was reorganized and expressed by topological connectivity graph based on strokes. Structural hierarchies of strokes were analyzed by the theory of network analysis, and then a multiple-criteria index was established to evaluated the structural importance of stroke, which took into account degree centrality, closeness centrality, betweenness centrality and length. The road mesh has been selected as a basic unit for analysis of areal hierarchy of urban road networks. The maximum enveloping area of urban road network has been hierarchically subdivided into a large number of the different hierarchical levels of road meshes by selected strokes according to priority established by according to its attribute level, structure level and principle of visual symmetry. Finally, the hierarchy and adjacency relationships between road meshes contained in road network have been expressed structurally based on binary tree model. The experiment results indicated that the method was excellent in the aspect of detecting all of road meshes in the road networks, establishing their spatial structure relationship and preferably reflecting areal hierarchical characteristic of urban road networks.