(GeoWorld, July 1996)
It is often said that "experience is what you get when you don't get what you want." The corollary to this universal truth is "learn from other's mistakes, so you won't have to make them all yourself." As GIS moved from its infancy in the early 1970's to its present maturity, the school of hard-knocks coughed-up an ample set of good, bad examples. We might not know what is best for all GIS environments, nor have the omnipresent formula for assured success, but the growing layers of scar tissue in the GIS community clearly point to the paths not to follow.
Given this line of reasoning, let me describe an early experience in the application of GIS to land use planning. It was a class project for a graduate course in GIS at Yale University in the spring of 1980. The saga pits a naive and somewhat dim-witted assistant professor backed by a covey of bright students against an enraged portion of the populace of Guilford, Connecticut, a picturesque town along Long Island Sound. But I am getting ahead of myself. The early stages of the project were typically blissful, with focused energy on data base development within the tender arms of academia. The students feverishly encoded twenty data layers for the nearly 70 square mile town, including the usual set from standard map sheets, augmented with special town maps, such as zoning, sensitive soils, and land use. This in itself was a great learning experience, given the pre-Paleolithic tools of the time.
Where we went wrong was an attempt to address a "real world" problem. The town had recently completed its Comprehensive Plan of Development and Conservation as a requirement of the Coastal Wetlands Act. It was the result of several years effort among citizen groups and town officials. The plan consisted of twenty-one policy statements, such as "protect inland wetlands ...from contamination and other modifications," "preserve farmlands," and "encourage development near or within existing developed areas."
Since all twenty-one of the statements had a spatial component, it seemed natural to map the conceptual model embodied in the plan. Using a three-tier ranking scheme of suitable, less suitable and unsuitable, each policy statement was interpreted into a map of suitability for development. For example, the policy to "preserve farmland" used the town's land use map to identify farmland and then assign the areas as less suitable. Similarly, the policy statement to "protect inland wetlands" caused these areas on the sensitive soil map to be designated as unsuitable. In contrast, the areas near or within existing development indicated on the land use map were identified as suitable for development. Following the plan's organization, the statements were grouped into four submodels of Water and Sewage, Growth, Preservation, and Natural Land Use, then combined into one overall suitability map.
Near the end of the term, enthusiasm was high and success seemed imminent. That was until we hosted a town meeting at the local high school to present the results. Students served refreshments and proudly stood by their computer-generated maps draping the walls. As fledgling GIS technocrats, they were eager to enlighten the audience as to the importance of the technology and the elegance of the map analysis process. However, the congregation seemed bored by the techno-babble and focused their collective attention on the final map of suitability. Once they located their property (you know, the parcel they were holding to pay for Sonny's college tuition), they did one of two things-- 1) profusely thanked the students for an undoubtedly thorough job and promptly departed to relieve the baby-sitter, or 2) lock the last student in the reception line in animated debate and, once pried loose, sat down in seething hostility. In less than a half-hour we had distilled our audience to a residue of enraged citizens holding "unsuitable" property. We left aboutmidnight and had to sneak back in the morning before basketball practice to recover what maps we could from the walls.
So what went wrong? We had done our homework. We had developed an accurate database. We had conscientiously translated their policy statements into maps and integrated them as implied by their plan. We thought we had done it all... and we had from a GIS-centric perspective. What we had missed is GIS's wildcard-- the human factor. The textual rendering of the comprehensive plan was comfortably innocuous as it lacked threatening spatial specificity. It seemed natural to outline a set of amorphous goals, then proceed with incremental planning whenever a developer proposes a specific parcel. If contention arises, there are always planning variances, exceptions, mitigation, and the ultimate recourse of lawyers and judges. This is the way things had always been done... the natural law of land use planning. The idea of an actual map of the spatial ramifications of a comprehensive plan is akin to poking a stick into a den a rattlesnakes. Any seasoned planner knows, you plan, then move on before you implement... it's dangerous out there.
Being a slow learner and somewhat bent on self-flagellation, I decided to extend the project the following year. First, the students refined both the database and the model, then determined the most limiting policy goals by systematically relaxing criteria in successive runs (sensitivity analysis). Armed with this insight, we solicited the help of the three town commissions instrumental in the plan's development; the Economic Development Commission, the Planning and Zoning Commission and the Conservation Commission. At working meetings, policy-rating questions were posed to each group andtheir hierarchical orderings of the policy statements where used for subsequent model runs.
The results were three maps of overall suitability, expressing alternative interpretations of the plan. For example, the Conservation Commission's interpretation of "protect inland wetlands" was emphatic. Since it's damp about everywhere, 83% of the town was deemed unsuitable for development. The Economic Commission, on the other hand, believed sound engineering protects wetlands, thereby lowering the wetland policy's rating, which resulted in only 21% being unsuitable. By simply subtracting the two maps, the locations of agreement and contention were easily identified. The comparison map and the three alternative interpretations by the commissions were published in the local paper... "healthy a priori discussion ensued." Most importantly, we minimized GIS student casualties.
The Guilford experience has forever altered my perspective of what GIS is (and isn't). Yes, it's hardware and software. It's a database. And GIS models. But, in actuality, it is the domain of the end-user and those impacted. Neither GIS Jerk nor Jock, can "solve" someone else's concern with rapid geo-query and pallet of 64,000 colors draped on a 3-dimension plot. In realworld applications, GIS acts as a communication tool in understanding the important factors, their interactions and various interpretations of both.
Source : InnovativeGIS.com
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