What is a Geographic Information System (GIS)?
A GIS is a computer application for mapping and analyzing geographic data. GIS combines many different types of data through a "layering" technique.
Layered data can then be analyzed using special GIS software to create new layers of data.
For example, data can be studied through spatial analysis. GIS can help validate theories and explore trends and patterns. Using emissions, plant monitoring locations, and demographic/health data, a user could buffer all plant locations by specified distances to examine how emissions relate to health in surrounding populations.