The national Crime Mapping Research Center calls itself a clearinghouse for crime-mapping research and development and will focus on developing, evaluating, and promoting research in geographic information system technology. Current technology includes touch-screen data terminals that can be mounted in patrol cars, in-car videos, and automatic vehicle location. A mapping system can indicate a community's physical, social, and cultural characteristics and can use hot-spot, radial, or grid analyses to examine crime in specific areas. Police officers in the field can use modems to send and receive information on their laptop computers. Data security, data integrity, maintaining databases, and downloading data as it becomes available, and training are issues that will require attention. However, this technology may help police officers become more effective. Examples of the use of mapping technology in police agencies in the San Bernardino County (Calif.) Sheriff's Department and the Charlotte-Mecklenburg, N.C., Police Department. Illustrations