A geographic information system (GIS) integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. GIS allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.
GIS is an interdisciplinary tool that has uses in nearly every industry. It helps you answer questions and solve problems by looking at your data in a way that is quickly understood and easily shared.
GIS gives us a new way to look at the world around us. With GIS you can:
- Map Where Things Are: Find places that have the features you're looking for and to see patterns.
- Map Quantities: Find places that meet certain criteria and take action. A children's clothing company might want to find ZIP Codes with many young families with relatively high income. Public health officials might want to map the numbers of physicians per 1,000 people in each census tract to identify which areas are adequately served, and which are not.
- Map Densities: A density map lets you measure the number of features using a uniform areal unit so you can clearly see the distribution. This is especially useful when mapping areas, such as census tracts or counties, which vary greatly in size. On maps showing the number of people per census tract, the larger tracts might have more people than smaller ones. But some smaller tracts might have more people per square mile—a higher density.
- Find What's Inside: Use GIS to monitor what's happening and to take specific action by mapping what's inside a specific area. For example, a district attorney would monitor drug-related arrests to find out if an arrest is within 1,000 feet of a school—if so, stiffer penalties apply.
- Find What's Nearby: GIS can help you find out what's occurring within a set distance of a feature by mapping what's nearby.
- Map Change: Map the change in an area to anticipate future conditions, decide on a course of action, or to evaluate the results of an action or policy. By mapping where and how things move over a period of time, you can gain insight into how they behave. For example, a meteorologist might study the paths of hurricanes to predict where and when they might occur in the future.
(adapted from esri.com)