A modified radius fractal dimension for capturing spatial complexity of a polycentric city

As one of the most important indexes for describing spatial complexity of urban road networks, radius fractal dimension has been proved to be useful in single-central cities. The method needs to choose a traffic hub as the center of measurement, but if the city has more than one traffic center, it will be difficult to choose a proper center and portray spatial complexity of the whole road network. The modified method proposed in this paper regards all the nodes of a network as centers of measurement and considers the whole effect of traffic centers in a polycentric city, so the modified radius fractal dimension describes the spatial complexity of a road network from an overall perspective and overcomes the problem that the traditional method relies on only one center. The experimental results show the modified radius fractal dimension is reliable, which can describe urban road networks in a new perspective.