WikiPLACE Second Pilot

WikiPLACE is a simple urban scenario-modeling system with the ease of use of a web -based wiki, combined with the power of numerical calculations. It uses the new "Federated Wiki" system now in development by wiki inventor Ward Cunningham.

WikiPLACE is able to calculate the predicted change to a given "externality," such as greenhouse gas emissions per person, in response to certain kinds of urban design changes. The changes are represented in the model by "patterns" -- descriptions of urban design features that fit into a network or "language."

As with any language, this "pattern language" is a flexible system that makes it possible to quickly construct different configurations and explore how they perform. The configurations can be easily adapted to specific kinds of problems and contexts. (That's why WikiPLACE is short for "Wiki-based Pattern Language Adaptive Calculator of Externalities.")

This second pilot version uses just five patterns, but in principle this kind of model could grow and evolve to become more complex in response to the particular problems being studied.

The five patterns are updated versions of classic patterns from the 1977 book A Pattern Language. The book was written by architect Christopher Alexander and his colleagues, but the system has proven to be useful in many other fields (notably software).

In this pilot version, only one metric is of interest: greenhouse gas equivalent emissions per person. Each pattern has been re-written to follow recent peer-reviewed research, and to generate a predicted reduction in greenhouse gas emissions per person.

The five patterns are:

Identifiable Neighborhood. Identify an area that includes the basic complements of neighborhood life: shopping, recreation, homes, workplaces. Place a network of through streets at no more than ¼ mile within this structure. Provide for retail and commercial along these through streets, especially at intersections. Provide for transit on these streets as well.

ONCE YOU HAVE IDENTIFIED THE AREA, you can explore patterns that can help you to improve neighborhood-scale performance.

Density Rings. Establish the overall density within the neighborhood, but use ring-like zones with greater or lesser density. Greater density is generally advantageous, but a range should be offered to meet varied needs and preferences.

Web of Transportation. Assure that transit is provided within a network of interchanges, such that pedestrians can find nearby transit lines, and transit riders can find convenient connections to other destinations. Assure that personal vehicles (cars, bicycles) are also accommodated.

Degrees of Publicness. Assure that the structure of lots provides a variety of zones between the most public and the most private.

Web of Shopping and Activities. Assure that opportunities have been provided to create retail, office, recreation and other elements of a complete community, within a general maximum spacing of ¼ mile.