Change Models are the core of a geodesign study. In the first iteration, these models ask what kinds of changes are on the horizon that may impact the AOI and influence the type of conceptual solutions put forward. In the second iteration, change models ask what strategy the team should use to approach change (design). Is the goal to protect and enhance what is already there and vulnerable to future change? This would be a defensive design strategy. Or is the goal to change the study area to accommodate and influence the direction of future change? This would be a more offensive approach.

In this lesson, we will learn to look to the site's context to understand different ways of designing. We will learn to determine the most appropriate approach: anticipatory or exploratory; offensive or defensive.

Anticipatory vs. Exploratory

To review what Dr. Steinitz presented in the video , Change Models can be either anticipatory or exploratory . If, after assessing the study area and problem, you already have a design in mind to solve the problem, your change model is anticipatory. You have anticipated the change. The purpose of an anticipatory model is to assess the suitability of a pre-conceived design. Conversely, if you do not have a design in mind, your change model is exploratory. You must evaluate the needs and context of the study area and explore several alternatives to determine a design that is most suitable for the place.

Offensive vs. Defensive

Another reason for selecting the change model is based on the scale of the study. Change models may also be offensive or defensive depending on the size of the area. As we have discussed in previous lessons, it is easier to advocated for and enact change at a smaller scale, allowing the geodesign team to pursue an offensive solution. McHarg's Richmond Parkway study illustrates an offensive approach to change. McHarg was able to advocate for and implement a new parkway that addressed a transportation and social issue (offensive strategy). The same strategy could not be employed for a much larger countrywide or global area, at least not with the same detail. The alternate option is to advocate for conservation (defensive strategy). At large regional or global scales, it is more difficult to control change, so the strategy shifts to determining locations where there is a desire for no change. There are other reasons for a defensive approach, such as conservation goals, stakeholder wishes, or as an alternative strategy.  Thinking back to McHarg's example of the New Jersey shore, levees could be likened to a more offensive strategy for defending the coastline, whereas conserving the dunes would be a more defensive approach.

Offensive vs. Defensive Strategies :(1) Levees (2) Dunes

In the second iteration change models, the geodesign team will have decided whether the change they seek is exploratory or anticipatory, offensive or defensive. The combination that is most suitable may inform how to best implement change over time.

Let's look at another example from Ian McHarg's work in this week’s reading. The study of the metropolitan region of Washington D.C. follows his typical methodology by assessing several physiographic features in the landscape as they relate to human development. No specific change was cited, but it is clear that the purpose of the study is to identify areas that will be most suitable to urban development in the future. In this study McHarg's change model is exploratory and offensive . However, with a slightly different emphasis in representation, it could easily be adapted into a defensive strategy (i.e. protecting areas that should not be developed). We can imagine how Representation, Process, Evaluation, Impact, and Decision Models were included in this straightforward analysis.