Physical environmental modeling, visualization and query for supporting landscape planning decisions

Landscape planners need to make decisions about the best possible mix of landuses and their spatial arrangement in the landscape based on accurate, detailed, diverse and spatially explicit information. Traditionally, static, map-based land classifications have been used to support landscape planning decisions. However, land classifications have lacked the flexibility and adaptability necessary for planning in complex landscapes with competing demands. With the increasing availability of spatial databases, physical environmental models, visualization techniques and the analytical capabilities of Geographic Information Systems (GIS), more effective decision support systems can be developed for landscape planning. This paper discusses the assembly of a multivariate spatial database of biologically significant physical environmental parameters (e.g. mean annual rainfall, minimum temperature, soil wetness) using environmental modeling techniques, and the visualization and interactive query of this database in landscape planning. Spatially distributed data layers of 21 parameters including climatic, soil, and hydrological parameters, are modeled on both the topographic and regional scale using physical environmental models linked to a GIS. Principal component analysis (PCA) is used to reduce the correlated data to five principal components (PCs) that capture over 91% of the physical environmental variation in the study area. The first three PCs were imported as bands of a 24-bit color image that enables the integrated multi-dimensional visualization of more than 83% of the environmental variation in the region. A prototype spatial decision support system called SimilarAreas was developed to provide an example of one type of interactive analysis useful in landscape planning that is possible with the database. SimilarAreas uses the concept of the environmental envelope [H.A. Nix, A biogeographic analysis of the Australian elapid snakes, in: R. Longmore (Ed.), Atlas of Elapid Snakes, Australian Government Publishing Service, Canberra, 1986, pp. 4-15] of sites that have been interactively specified by the user and identifies other geographical areas with statistically similar environments to those specified using the environmental database. The system enables landscape planners to pose general queries like "Show me all areas with environments similar to these." Specific application examples of SimilarAreas are provided in viticulture site planning and habitat restoration although potential applications of the modeling, visualization and query techniques described in this paper are much more diverse.