Robustness Analysis of City Road Network at Different Granularities - Space-Time Integration in Geography and GIScience - page 137

Fig. 8.8 Topological form of community-based road network under attacks

under attacks till split into disconnected components. The variation in road network
sparseness between different columns indicate that road network can still operate
even the network is sparse under random attacks. But under intentional attacks
especially betweenness based attacks, even the network seems density, the split will
cause the network malfunction.
To provide the topological changes of network under attacks, we visualize
the topological form of community-based urban road at different level of the
betweenness based attack process in Fig. 8.8 .
The above sub figures in Fig. 8.8 presents the layouts of community-based dual
graph under attacks according to the three stages of the network changes. We can
see that in the second stage, the network split into three disconnect components.
The network becomes malfunction by collapsing into small pieces in the third
stage. The below sub figures in Fig. 8.8 show the layouts of community-based dual
graph of different node removal rate. When 5 % nodes are removed from the initial
network, the network haven't split although the topological form of the network
changes. But when 10 % nodes are removed, the network is split into several
pieces.
Figures 8.7 and 8.8 provide a clear conception of spatial change of urban road
networks under attacks. From which we can figure out how the structure of network
changes under different strategic of attacks.