Topological analysis on vulnerable spots of a city

In this paper, the methodology to evaluate viability of a city is proposed. First, districts in a city are classified into two groups, based on the difference between the distributions of population and facilities. One is the group of districts with a relative abundance of facilities, and the other is the group of districts with a relative shortage of facilities. Then only the roads that connect the districts with a relative abundance of facilities and the districts with a relative shortage of facilities are regarded as effective links from the viewpoint of efficient use of facilities in a city. Topological index of the graph consisting of effective links is calculated to evaluate the ability of complementing functions. The application of the methodology to some cities is also shown