What is the primary function of Geographic Information Systems (GIS)?

The primary function of Geographic Information Systems (GIS) is that it serves as a computer-based tool used to collect, analyze, and visualize geographic data. GIS integrates hardware, software, and data to enable users to capture, manage, and analyze spatial and geographic information. This functionality allows for the representation of data through various forms, such as maps, charts, and reports, making it essential for decision-making processes related to urban planning, environmental management, resource allocation, and many other fields that rely on spatial data.

In this context, while mapping historical events and their impacts can be a specific application of GIS (as seen in the second choice), it does not encompass the full scope of GIS's capabilities. Similarly, regulating urban land use and evaluating environmental policies can involve GIS, but they represent particular uses rather than the primary function of the technology itself. Thus, the broader description of GIS as a tool for collecting, analyzing, and visualizing geographic data accurately captures its essential role in geography and related disciplines.