Wednesday, November 25, 2009

Networks, cities and trees

Occupying and connecting. Frei Otto. 2009. P.51

The image above is provided by Otto in support of his argument that human spontaneous networks of urbanity follow similar patterns to ones formed in nature through the structures of leaves, insect colonies or soap bubbles. The attractive part of this argument has to do with an energy analysis. Since none of these networks mentioned is formally planned, their form is the outcome of an evolutionary process favouring systems with a minimal energy path or more accurately an energetic equilibrium. In a similar manner our own organic non-planned communities, such as medieval villages follow those patterns, which minimize energy expenditure. This may lead us to one of two possible conclusions: 1. we need not bother with urban planning, as the emergent self organization would take care of itself in the most efficient way, or 2. our planning should be informed by these processes and at best imitate their operations to 'become one with nature'.

Network types by Paul Baran, developer of the distributed communication network system, early 1960's

In criticism of some of these interpretations, as well as his own earlier assumptions, Christopher Alexander's article from 1965, "A city is not a tree", claims that the tree (or centralized, hierarchical) structure is simplistic, limited and limiting when applied to city planning. Alexander argues that our current needs embody a higher level of complexity than the tree structure permits. He proposes a three dimensional 'semilattice' network (not unlike the distributed system above) which allows for multiple overlapping to occur, as well as provides non hierarchical means of connectivity. Although published almost half a century ago, these ideas may still prove relevant especially with our growing familiarity with distributed complex communication networks such as the Internet. As we develop our social network understanding in a more distributed way, the question still remains: how does this affect city planning? Is the omnipresent grid laid out obliterating any landscape and context the way to go? Minimal energy path tree structure with its obvious limitations? Or could (and should...) the semilattice network materialize and be manifested beyond the virtual world? I would love to get some comments on these issues from anyone out there..