The utility of semi-formal models in ecological planning

Abstract

A model is an abstract representation of reality. For centuries, designers and planners have constructed three-dimensional models to study and illustrate visible form. Over the past half century, investigators in a variety of disciplines have expanded the modeling concept to represent invisible processes and relationships. Processes represented are extremely diverse; examples include the dynamics of predator-prey relationships, the varying trajectories of ballistic missiles under different atmospheric conditions, traffic flow, and organizational flux in a large corporation. In most cases, such models are formal, mathematical and highly quantified. Formal mathematical models have proven difficult to use in landscape planning and design for a variety of reasons including the complexity and seeming randomness of the situations and the lack of quantitative data. However, the concept of using models as a means of making invisible processes and relationships tangible is extremely useful. Most useful of all are models that define the relationships between these processes and the visible form of the landscape. By eschewing formality and strict quantification and adopting an adaptive and pragmatic approach to modeling, we can use models in planning and design processes in creative ways. We might call this semi-formal modeling because the models produced have definite form and consistency without the rigid formality of strict quantification. They can represent processes and relationships along with physical landscape forms in general or specific ways. But they are not casual or sloppy. We might define a few principles of semi-formal model application as follows: 1. (1) Models representing processes and their relationships to physical form are most useful in addressing the key issues of a project, especially those involving the modes of ecosystematic order: structure, function, and locational patterns. 2. (2) Models should be as visual and communicative as possible. 3. (3) Models are ideally as complex and inclusive as needed for the purposes of the project and no more so. 4. (4) Model-making generally proceeds from the qualitative to the quantitative; quantities are usually useful where they are available but usually dispensable where they are not. 5. (5) Models can represent change over time; the key changes for planning are usually those from the past to the present to the future. 6. (6) Models provide a medium for progressing from process to form in processes of planning and design.