Figure 1.
The geography of talk in Great Britain.
This figure shows the strongest 80% of links, as measured by total talk time, between areas within Britain. The opacity of each link is proportional to the total call time between two areas and the different colours represent regions identified using network modularity optimisation analysis.
Figure 2.
Defining regions through the spectral modularity optimization of telecommunications networks.
a - even with just three regions we obtain a total modularity of 0.31, indicating a fairly good network partitioning. b - the final partitioning of Great Britain yields a modularity of 0.58. c - further fine tuning according to the process suggested by Newman [16] increases the modularity to 0.60.
Figure 3.
By combining the output from several modularity optimization methods we obtain the results shown in this figure. The thick black boundary lines show the official Government Office Regions partitioning together with Scotland and Wales. The black background spots show Britain's towns and cities, some of which are highlighted with a label.