Analysis and design in computer-aided physical planning

In physical planning, two stylized approaches to plan-making may be distinguished. In the analytical approach, the purpose is to determine optimal adjustments to the current spatial structure in order to resolve an existing planning problem. Global planning objectives and restrictions are reduced to well-defined criteria, variables, and threshold values. Next, this formalized model is applied to empirical data. GIS tools are typical for this approach. The focus of the design approach is on shaping a new spatial structure. Through visualization of successive conceptual designs, the mental maps of the participating planners gradually evolve into a coherent perspective for the plan area. CADD tools are used in this process. In this paper the author discusses how these two approaches can be merged into one interactive computer-aided plan-making process: a two-way, cyclic interaction between parallel and consecutive phases of analysis and design. In one direction, customized analytical information supports the issues in design. In the other direction, intermediate design results are operationalized for analytical evaluation. An example is presented and the tools required are discussed.