Some times decision problems are a bit more complicated or complex. Carl Steinitz (40 years of GIS at Harvard) developed a landscape modeling workflow process to address complex, regional planning decision problems, we will call a nuanced workflow. The workflow can be used for planning, improvement programming and project implementation. However, the content, structure, process, and context of decision problems would likely be different since the information needs are different in each of those situations.
The six-phase nuanced workflow method has been applied in practice in several GIS-related projects that address urban-regional landscape issues over the past ten years or so around the world (See the bibliographic references to Steinitz in the textbook). In January 2010 at a GeoDesign Summit, Esri President Jack Dangermond highlighted the Steinitz landscape modeling approach calling it one of the foundational methods in GeoDesign.
Phases are framed by a set of critical questions that you can ask yourself (or your colleagues).
- 1) Representation Modeling
- In a nuanced method, GIS analysts should be asking questions like:
- - How should the state of the urban-regional community with regard to the particular issue at hand be described in terms of a database design that is modeled as value trees or value hierarchies?
- - What data categories are to be represented by measurements of attributes, space, and time?
- - Whose concerns about these design questions should we consider? Are there other groups that should be consulted to make sure we have incorporated all the relevant data into the representation model?
Complex decision problems are fraught with various interpretations of concerns about urban-regional communities. Stakeholder perspectives from diverse groups, even if these are groups within a single organization tend to align with various concerns, often these are called stakeholder interests. It can be said that those differences of interest are the basis of stakeholder groups. Working with a variety of stakeholder groups on an oil leasing decision problem in the Santa Barbara Channel, Edwards and vonWinterfielt (1987) organized stakeholder interests into value trees (values, goals, objectives, criteria) to show the similarities and differences among environmental, social and economic objectives and criteria according to different stakeholder groups. Where did the information from Table 3.2-3.4
come from for arriving at a database design (content categories and structure of the database)?
Lot more on value trees and databases when we get to a deeper look into database design…
- 2) Process Modeling
- Several questions could be posed related to a process model.
- - If a representation model forms a categorical content and structure foundation for a process model, then how might we examine relationships among land use, transportation, and environmental elements over time as a basis for articulating process?
- - What are the relationships among the spatio-temporal elements, such as land use and transportation, that provide us insight and better understanding of urban-regional process?
- - What land use, transportation, and or water resource processes do we need to consider?
- - How does the land use, transportation, and or environmental transformation process work?
Urban-regional growth processes need be considered if we are to better understand how communities change. Porter (1997) characterizes growth in America’s communities as being mostly driven by land use change. Landscape change is commonly a land use change issue (Steinitz et al. 2004). Land use change is supported by access to transportation, as it is very difficult to get to places without transportation infrastructure, e.g. like highways or bikeways. The land use and transportation theme connection is fundamental in growth management. Graphic in Figure 3.6
shows a process of wastewater flow.
- 3) Scenario ModelingSeveral questions could be posed as related to a scenario model.
- - How does one judge whether the current state of the urban-regional environment is working well?
- - What are the metrics of judgment, e.g., esthetic beauty, habitat diversity, cost, nutrient flow, public health, public safety, and/or user satisfaction, in order to evaluate the nature of change?
- - Which of these do we want to consider in a scenario? How many can people consider without getting lost within an information glut?
A process model forms a functional foundation for a scenario model. Scenario models develop out of tweaking assumptions about processes, as we can change the input to a process. Given a different set of assumptions about how change might occur, we can generate a variety of scenarios. Sometimes people refer to scenarios as “worst case” or “best case”. Those references must be explicit about what “worst” means and what “best” means. This comes back to understanding values, goals, objectives and criteria that are part of scenario descriptions. Figure 3.7
highlights a portion of wastewater flow.
- 4) Change Modeling
- Several questions could be posed as related to a change model.
- - By what actions might the current representation of the urban-regional landscape be altered, whether conserving or changing the landscape in regards to what, who, where, when, how much, how many, etc.?
- - At least two important types of change should be considered. One is how the landscape might be changed by current trends. Modeling trend leads to a projection model as the basis of change.
- - A second could be, how might a community be changed by implementing design action? This leads us to developing intervention models as the basis of change. Intervention is a pro-active approach to change.
- - Again, how many variables can we consider in these models before being overwhelmed?
Many people say that the only constant in the world is change. A scenario model forms the basis of what to consider about change. Scenario models provide a foundation for change models as we take the “before conditions” and contrast them with “after conditions” for a particular scenario. The result of social, economic and environmental conditions that differ in a major way(or not) is the outcome of a change model. Plate 3.1
shows result of a change due to siting a facility.
- 5) Impact Modeling
- Several questions could be posed as related to an impact model.
- - A change model forms the basis of “what content, structure, process” change are important enough to consider as impacts, i.e. major changes that matter to someone?
- - What predictable impacts, i.e., the outcomes of changes, might those changes influence and/or cause?
- - What impacts are less predictable because changes and processes are not well understood?
Impact models are perhaps more difficult to construct than the previous models, because impact models rely upon good information output from all of the preceding models. Impacts due to urban-regional growth - whether land use impacts, transportation impacts, water resource impacts - are difficult to estimate. The difficulty arises from what is not known about processes. Although considerable data exist, when it comes to modeling impacts, we never seem to have enough of the right (aka appropriate) data. Figure 3.8
shows land parcels outside the river buffer that have not been excluded from site selection consideration.
- 6) Decision Modeling
- Several questions could be posed as related to a decision model.
- - How is a decision to change, conserve, and/or improve the “landscape” to be made in regards to urban-regional impacts?
- - How can a comparative evaluation be undertaken based on a sensitivity of impact change among alternative courses of action?
- - How are we to treat impacts in an equitable manner?
The reason this nuanced workflow process is so interesting is that the final model phase is a decision model. GIS has for a long time been touted as a decision support system (Cowen 1988). However, this nuanced workflow process makes this idea explicit and clear because of the inclusion of the decision modeling phase. One thing to remember is that all previous models lead to this model. An impact model forms the foundation for how to characterize alternatives for a decision process as in Figure 3.9
. Weighting of objectives (site criteria), whereby area size is given the most weight (20 out of 100 points), and elevation and distance to floodplain the least (10), generates map in Figure 3.10, whereby site 64 is ranked the highest. When we trade-off one impact against another we can set priorities for what we value. Chapter 7 of this book will get into much more detail about these issues.
Facing UNCERTAINTY in Modeling
- What if we do not have the time, resources, insight, and/or data to undertake all of the above models? If not, then we introduce information uncertainty into the GIS workflow process. It is better to know by intention than by ignorance.