To compare these communities we have worked within the emerging methodology of "historical GIS." GIS, or Geographic Information Systems, permits historians to ask spatial questions, to represent spatial information, and to produce spatial statistical analysis. Social scientists, historians, legal scholars, and geographers are engaged in historical GIS work. Archeologists were among the first social scientists to work with GIS, and it has been used to study ancient civilizations, Native American societies, and human settlement patterns in prehistoric Western Europe. A special issue of Social Science History in Fall 2000 was dedicated to "Historical GIS: The Spatial Turn in Social Science History."

Historical GIS work is underway in a range of periods and areas. For example, Amy Hillier has examined spatialized data on 1930s Philadelphia to test whether New Deal policies led to redlining (restrictive loan policies). Geoff Cunfer has worked on the causes of the Dust Bowl with geospatial data on weather, climate, and agricultural practices to test whether land-use practices were to blame for the disaster. Trevor Harris has developed a "participatory GIS" approach to questions of land use, ecology, forced removal and relocation in post-apartied South Africa. David Germano's pioneering Tibetan and Himalayan Digital Library applies GIS to assemble cultural, environmental, and historical materials on the region into an accessible and geographically connected archive. In addition, scholars are studying Chinese fertility patterns, regional economic development patterns in the United States, and the geography of literacy and print culture in world history.

Most of these historical GIS studies connect local experiences and geographies to larger interpretations of national or global patterns and events. Our GIS begins with historical maps of Franklin and Augusta counties, each with thousands of named points, including residences, businesses, roads, streams, railroads, even footpaths. These detailed maps feature block-by-block, house-by-house renderings of the major towns and cities in each community. We have traced these features into a comprehensive GIS for each community, and we have integrated for each point on the map, whether household or business, a range of other data from the Valley project, including population, agricultural, slaveholding, and manufacturing census information. In addition, political and religious affiliations for each household have been drawn from newspapers, church records, letters, and diaries. The complete GIS allows us to ask comparative questions of the spatial relationships within these communities and to examine closely the social, economic, and political arrangements within each. The GIS data set will can be published separately from this article and as new technologies develop it might be presented in a dynamic format online. The GIS has provided the dozens of detailed maps and tables in the evidence section of this article.

The GIS for this article was developed in collaboration with a team of graduate and undergraduate researchers working with the authors. At each stage we made key decisions about the structure and design of the GIS. The team documented our decision making process and the procedures for our work at each stage over the two years it took us to complete the GIS. For a detailed description and guide of our step-by-step process to create the Augusta and Franlkin GIS, please see our team's "Development of a GIS Database" and the "Methodology For Creating and Analyzing a Census/GIS Database " documents in this section.