Sonoran Adaptation Residential Growth Model A growth planning and allocation model joined with a geospatial statistical model using random choice logic within the R statistical software package, combining macro and micro economic and demographic analysis with fine scale distance to amenities and services measures to develop an adaptable model and GIS methodology for predicting and allocating residential growth in the urban interface communities throughout the Western US. The model currently grows population over 4 time periods (typically decades) and allows local planners to use simple COmmunityViz sketch tools to add new planned unit developments (PUDs) and subdividsions. Growth from the model is allocated to neighboring areas with a variety of modeling options. The model uses Python scripting to combine the GIS inputs and outputs with the R statistical program software. The model can be used with a suitability analysis, and model resutls can be compared with common impacts analysis and scenario comparison.  Base data developed by GIS analysts from local government sources, Applied to predict number of structures placed for a time step, in this example the 2000-2010 time stamp Process iterates three times to produce results for 2020, 2030, 2040 time steps
The purpose of this process is to predict the number of structures that will be built during each time step  Diagram represents the spillover process of allocating residences that grow from model parameters but exceed local zoning density for a given area. Quarter sections were used in this analysis representing an area 1/2 mile wide and long). For example an area has capacity of 10, and 14 structures predicted there after a decade of growth , spillover of 4 structures. Spillover is allocated to nearby areas spiraling out until all new residences are placed in areas allowing the additional density. The process is iterated for each time period. The planner can use CommmunityViz to create alternative scenarios based on teh original base scenario. These can include alternative growth strategies, different size and locations of planned unit developments and new communities, cluster or dispersed development patterns, changing land uses, or alternative zoning and density capacity examples. | Project Examples Dona Ana County, New Mexico 
Dona Ana COunty was the pilot project for the Sonoran Adaptation project. It has an established agricultural and rural lifestyle, strong sense of community, natural areas, mountains and deserts, New Mexico State University, and in expanding "snowbird" population of retirees who live there seasonaly. The county is one of the fastest growing counties in the US with a large hispanic population and a 10.5% increase over the last 6 years. Approximately 25% of the population is below the poverty level. The growth model predicted residential growth amounts and pattern of development for 2010, 2020 and 2030.
High Divide Counties, Montana 
The Sonoran Institite contracted with Geodata Services, Inc. to examine the GIS data analysis and data preparation required to run the growth modeling. A number of factors were identified to streamline the process, and make it less expensive and more efficient. Over 30 counties in Montana, Idaho and Wyoming were surveyed and 6 Montana counties were selected for subsequent growth modeling. By making extensive use of ESRI Business Analyst and Business Analyst Online, the data processing was significantly enhanced and processing time dramatically reduced. The key limiting factor to widespread use of these type of growth models is availability of detailed residential location mapping, typically relying on local government and municipal mapping of private land parcels. Montana, one of the only states with complete parcel and cadastre mapping was selected for this analysis in order to compare automated methods using ESRI Business Analyst, with complete US coverage to the labor intensive processing or parcel data. Results will be available in the autumn, 2008. To see details on the data used in this growth modeling click the link below: Data used in the analysis
Gallatin County, Montana 
Gallatin County, Montana was the second pilot for the growth model integration with CommunityViz. In this instance, we were exploring the use of CommunityViz Sketch Tools, providing an easy way for planners with limited GIS experience to change density measured in dwelling units per acre. A different twist on this pilot was to examine the pattern of growth in retrospective fashion, going back in time to the late 1990's and predicting forward to 2005 and on into the future using a scenario of directed growth to the incorporated and zoned areas of the county, and cuting back uncontrolled sprawl into the urban/wildland interface. Drive time zones were overlaid and an assessment of road impact fees compared new road costs between alternatives. Image gallery of scenario comparisons Common impacts analysis comparisons
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