Quantifying How Haussmann Changed the Function and Form of Paris

"[A] new study by a collaboration of mathematical physicists and social historians in France shows that, simply by analysing old and new maps of the city, it’s possible to quantify what effect Haussmann’s plans had on the shape and life of Paris," reports Philip Ball. "The results offer a case history of how cities may evolve through a combination of spontaneous self-organisation and top-down central planning."

"Marc Barthelemy of the CEA Institute of Theoretical Physics in the Parisian suburb of Gif-sur-Yvette and his colleagues have analysed maps of the city road network at six moments in time since the Revolution began: 1789, 1826, 1836, 1888, 1999 and 2010. They looked at some basic properties of the networks, such as the numbers of nodes (intersections) and edges (roads between intersections), as well as using more sophisticated concepts from the modern theory of complex networks, such as the quantity called 'betweenness centrality' (BC) that measures the importance of individual nodes to navigating the network."

"The results are revealing," says Ball. "Whether or not Haussmann made a difference depends on what you look at."