  Large-scale networks of human interaction, in particular country-wide
telephone call networks, can be used to redraw geographical maps by applying
algorithms of topological community detection. The geographic projections of
the emerging areas in a few recent studies on single regions have been
suggested to share two distinct properties: first, they are cohesive, and
second, they tend to closely follow socio-economic boundaries and are similar
to existing political regions in size and number. Here we use an extended set
of countries and clustering indices to quantify overlaps, providing ample
additional evidence for these observations using phone data from countries of
various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium,
Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known
approach of partitioning country-wide networks, and an additional iterative
partitioning of each of the first level communities into sub-communities,
revealing that cohesiveness and matching of official regions can also be
observed on a second level if spatial resolution of the data is high enough.
The method has possible policy implications on the definition of the
borderlines and sizes of administrative regions.
