Management information systems (MISs) provide decision makers primarily middle managers with preselected types of information. A decision support system (DSS) helps middle and executive managers organize and analyze their own decision making information. Executive information systems (EISs) are decision support systems customized to meet the special needs of executive managers. A geographic information system (GIS) is an information system that combines geographic information with other types of data in order to provide a better understanding of the relationships among data. Enterprise-wide systems include electronic data interchange (EDI), enterprise resource planning (ERP), and inventory management systems.