Evaluation of Properties to determine the Importance of individual Roads for Map Generalization

Many researchers have paid much attention to the importance of individual roads for various applications such as traffic flow analysis and road network generalization. This paper gives a comparative analysis of different properties to determine the importance of individual roads for road network generalization purpose. These properties include one geometric property (length); three topological properties (degree, closeness and betweenness) and one thematic property (road class). Two representative selective omission approaches (stroke-based selection and mesh densitybased elimination) are implemented to generalize road network. For each approach, different properties are respectively used to determine the importance of individual roads. The road network of Hong Kong Island is used as study area for testing and two measures (similarity and connectivity) are employed to evaluate the selections. Results show that, when the stroke-based selection approach is implemented, using length performs best in determining the importance of individual roads, and using betweenness or closeness performs well in preserving the connectivity of the retained network; when the mesh density-based elimination approach is implemented, all these properties have quite similar selections.