GIS can be used in many ways to support public health. It allows researchers to construct disease models, track disease spread over space and time, and identify high-risk areas. GIS is also used to plan infrastructure and services by analyzing data on roads, population statistics, and medical resources. It helps with site selection for facilities like reservoirs by integrating data layers like vegetation, soil type, and drainage patterns. Overall, GIS is a powerful tool for public health planning and decision-making by allowing spatial analysis and visualization of relevant data.