What is the purpose of "overlay analysis" in GIS?

The purpose of overlay analysis in GIS is to combine different data layers to find relationships between them. This process involves superimposing multiple datasets that contain information about the same geographic area. By doing so, GIS professionals can identify patterns, correlations, and interactions across different types of data. For instance, an overlay analysis might be conducted to determine how land use data interacts with environmental features, allowing for insights into how residential areas might affect watershed health.

When different layers are overlaid, it becomes possible to analyze the spatial relationships between features, such as how many parks are located within a certain distance of schools or how environmental policies impact urban development. This form of analysis is fundamental because it enhances decision-making, planning, and resource management by providing a clearer picture of how various factors interact in the geographic space.

This process does not involve the creation of 3D projections, isolation of individual data points, or temporal changes, which are distinct methods and purposes within GIS analysis.