Integrated Approach of Spatial Metrics by Graph-based Road Network on Remotely Sensed Imagery for Urban Transportation Planning

In these days, remotely sensed imagery has been widely used for GIS-T (Geographic Information Systems for Transportation). As for this approach, topological measure and spatial metrics of transportation network structure such as road layer can be considered as one of important factors in urban transportation analysis. Related to this measure, it is known that the connectivity such as alpha index and gamma index which means degree of network connectivity and complexity on a graph or a circuit, provide useful information for urban transportation planning. As well, shimbel index is one of GIS-based spatial metrics to characterize degree of network concentration. However, the approach using these quantitative indices has not been widely used in the practical level dealing with actual data sets yet. While, as other spatial metrics, circuity terms a concept to represent the difference extent between actual nodes and fully connected nodes in the target analysis zone, and accessibility is used to represent accessibility level in the matrix form by connectivity level between node to node in a zone. In this study, several spatial metrics functions, such as connectivity, accessibility, and circuity, mentioned above were first implemented to extract transportation indices from a graph-based network. In conclusions, new quantitative information to characterize an urban transportation environment in a certain region can be easily obtained and utilized as meaningful indicators related to transportation planning process or urban transportation planning.