Centers for Disease Control and Prevention: GiS and Public HealthGeography is the study of how the world differs from place to place. Geography uses a spatial, or geospatial perspective, meaning it focuses on place and space, looking at what, where and why phenomena occur. Geographers use a variety of tools to study these topics such as maps, statistics, and Geographic Information Systems (GIS). GIS is a computer system consisting of hardware and software used to store, manipulate, analyze, model, and display spatial and non-spatial data.