Connecting the Fractal City

Living cities have intrinsically fractal properties, in common with all living systems. The pressure to accommodate both the automobile and increased population growth led twentieth-century urbanists to impose anti-fractal geometrical typologies. The fractal properties of the traditional city were erased, with disastrous consequences for the urban fabric. To undo this damage, it is necessary to understand several things in some detail: (i) what these fractal properties are; (ii) the intricate connectivity of the living urban fabric; (iii) methods of connecting and repairing urban space; (iv) an effective way to overlay pedestrian, automotive, and public transports; and (v) how to integrate physical connections with electronic connections. First of all, some basic misunderstandings about fractal structure have to be cleared up. I will then underline the nature and importance of hierarchical coherence. We can use the fractal criterion to test the geometry of cities as one condition for their success. Another independent criterion is connectivity, which has to be studied topologically. I will use lessons learned from the evolution of biological systems and the internet to discuss the distribution of sizes, inverse-power scaling laws, and 'small-world' networks. These concepts show us that extreme densities favored in contemporary urbanism -- suburban sprawl on the one hand, and skyscrapers on the other -- are pathological. The challenge for the contemporary city is how to superimpose competing connective networks in an optimal manner.

Keynote speech, 5th Biennial of towns and town planners in Europe (Barcelona, April 2003). The text is going to be pulished in "Principles of Urban Structure", a new book by Nikos Salingaros, Delft University Press.
© Nikos Salingaros