The What If ? Planning Support System

This paper describes What if? , a scenario-based, policy-oriented planning support system (PSS) that uses increasingly available geographic information system (GIS) data to support community-based processes of collaborative planning and collective decision making. It incorporates procedures for conducting land suitability analysis, projecting future land use demands, and allocating the projected demands to the most suitable locations. The system allows users to create alternative development scenarios and determine the likely impacts of alternate public policy choices on future land-use patterns and associated population and employment trends. It is easy to use, can be customized to the user’s database and policy issues, and provides outputs in easy-to-understand maps and reports. INTRODUCTION The field of urban and regional planning is experiencing two fundamental changes that are having a profound impact on the use of computer-based models in planning practice and education. On the one hand, the dramatically increased availability of powerful, lowcost, and easy-to-use GIS software, and more extensive spatially referenced data, are making GIS an essential tool for planning tasks such as land use monitoring, code enforcement, and permit tracking. However, with this increased use has come an increased realization that GIS alone cannot serve all of the needs of planning (see, e.g., Couclelis 1991; Harris 1989; Harris and Batty 1993). This realization has renewed planners’ interest in computer modeling and stimulated the development of planning support systems that combine GIS Paper 10 of Planning Support Systems: Integrating Geographic Information Systems, Models, and Visualization Tools excerpted and reprinted courtesy of ESRI Press. Copyright © 2001 ESRI. All rights reserved. The entire book can be purchased online at www.esri.com/gisstore or by calling 1-800-447-9778. 264 10: The What If? Planning Support System Copyright © 2001 ESRI. All rights reserved. (and non-GIS) data, computer-based models, and advanced visualization techniques into integrated systems to support core planning functions such as plan preparation and evaluation (see, e.g., Finaly and Marples 1992; Holmberg 1994; Klosterman 1997). On the other hand, planners are increasingly abandoning the attempt to “plan for” the public in favor of more collaborative efforts to “plan with” the public. These attempts take a variety of forms, such as strategic visioning conferences, design charettes, and other community-based collaborative planning and consensus building efforts (see, e.g., Godschalk et al. 1994; Lowry et al. 1997). These efforts attempt to involve private citizens and other stakeholders directly in the planning process to help identify and prioritize the public’s needs and desires, explore alternative development scenarios, and establish benchmarks for evaluating ongoing development efforts. These carefully structured consensus building processes can help achieve the ideals of communicative rationality and traditional comprehensive land-use planning (Healey 1992; Innes 1992; Innes 1996). What if? is an interactive GIS-based planning support system that responds directly to both of these trends. It uses the GIS data sets that communities have already developed to support communitybased efforts to evaluate the likely implications of alternative public policy choices. It provides a single integrated package that allows planning tasks that now require weeks or even months to do to be completed quickly and easily. The package can be customized to a community’s existing GIS data, concerns, and desires, and provides outputs in easy-to-understand maps and reports which can be used to support community-based collaborative planning efforts. 1 Reflecting the movement from “planning for the public” to “planning with the public,” What if? assumes that planning and policymaking should not be based on closed and unsupervised “objective” analysis of technical experts. Instead, it provides a set of computerbased tools which facilitate open and ongoing processes of community learning, debate, and compromise. By providing information, techniques, and evaluation criteria which can be used to support particular public policy perspectives and critique others, it supports explicitly political processes of “adversary” or “counter” modeling similar to Davidoff’s (1965) advocacy planning model. By involving the public directly in the planning process, it constrains the discretion of professionals and political insiders, reduces the knowledge