concepts. The students were given a lengthy handout, with a detailed list of economic behaviors that urban models should represent.
The GIS Models
In , the students read Wegener (1994) and Simmonds (1995), both good overviews of urban economic models, to reinforce the lecture in Week One that reviewed urban models broadly, including GIS models. Johnston lectured on UPlan and demonstrated it in the lab. The students read Johnston et al. (2003) describing this model. UPlan was demonstrated first, as it is the simplest model in the course. It runs in ArcView3.2, the most commonly used GIS software for governments in the U.S., and allocates land uses based on user-set rules. The students ran UPlan on one county in the Sacramento region (Placer Co.) that has severe conflicts among urban development, farming, and habitat protection, and designed and evaluated two land use scenarios for their impacts on farming and habitat values. The students saved their maps and written papers in folders on the lab computers. This assigment went well, with the software running correctly and the students understanding the model’s capabilities and limitations fairly well.
In , the PLACES land use and transportation accounting tool was demonstrated. This is a fairly complex GIS tool intended for scenario generation and evaluation. PLACES development was supported by the USEPA. It also runs in ArcView3.2. For scenario generation the user selects from a list of land use types and clicks them onto polygons (parcels, or planning areas in a county). This links the land use types table to the polygon table, a basic ArcView function. The benefit of this tool is that it can run in real time, returning results within a couple of minutes. One can also mark a