Geographic Information Systems (GIS) play a crucial role in disease surveillance and in understanding the spread of chronic diseases by integrating spatial data with health information. GIS enables the collection, storage, analysis, and visualization of geographically referenced health data, which helps public health authorities identify patterns, trends, and risk factors associated with diseases. By linking disease occurrence with location-based variables such as population density, environmental conditions, and access to healthcare facilities, GIS supports evidence-based decision-making and effective intervention planning. In disease surveillance, GIS is widely used to monitor the spatial and temporal distribution of infectious and non-infectious diseases. Health data such as case reports, hospital admissions, and mortality records are mapped to specific locations, allowing authorities to detect disease clusters and emerging hotspots. For example, during outbreaks of dengue or malaria, GIS helps map cases in relation to breeding sites, rainfall, temperature, and urban infrastructure.