The map to the left is a graph of a social network of mayors:

We are seeing more and more interest in "regional economies" all over the world. One of the key players in regional economics are the mayors of the cities in that region. How are the mayors in your region connected? Are they exchanging ideas? Are they assisting each other? Or are they chasing smokestacks and high tech labs, and only competing with each other?

Above is a network map of mayors from a small country in the European Union. The population of this country is around 5 million, about the size of typical economic region. The nodes, representing each mayor, are colored by political party.

Want to know how to interpret the map? Go read Valdis's post.

(Found via Patti.)