Geographic factors, such as the location of alcohol outlets or of neighborhoods with different socioeconomic status within an area, can influence the patterns of alcohol use and alcohol-related problems in that area. Geographic information systems (GIS)--computer-based systems to capture, store, retrieve, analyze, and display spatial data--are increasingly used to investigate the effects of such geographic factors. GIS offer several key capabilities that facilitate alcohol-related geographic analyses, including geocoding (the linking of descriptive data, such as driving-while-intoxicated [DWI] events, to a location on a map), informative visual displays, and calculation of distance and adjacency. Using GIS-based data, researchers can perform complex spatial analyses of alcohol-related behaviors and problems, such as determining the correlation between DWI rates and geographic locations. These types of analyses may help investigators to understand environmental influences on alcohol-related problems and to plan and target appropriate prevention and intervention approaches.