GIS = Geographic Information Systems
GIS is a collection of software, data, and people that supports mapping, analysis and decision making. GIS enables you to interact with data spatially in ways that tables, charts and static maps cannot achieve. For further reading, check out Penn State's open GIS textbook: The Nature of Geographic Information.

Here are some examples of what GIS can do:

• Determine trends in desertification of an area based on rainfall data, soil samples and infrared signatures captured by satellites/aerial imagery. An additional step would be to predict relative health of plants or crops.
• Determine from flood and traffic density data the best routes for hurricane evacuation from a coastal town.
• Discover book publishing patterns in the British Isles during the Middle Ages using publisher data from catalogs and archives.
• Model how an epidemic might spread through a population.
• Predict the best location for a business based upon demographic data and trends in related businesses for the area of interest (image below shows a proposed gym location overlaid with distance/drive times and patrons (the color-coded points) that attend the two existing gym locations).

GIS in Practice

Here are a few projects and organizations utilizing GIS in their work. 

• Mean Green Mapped: This map uses current GIS layers combined with historic maps and photos from the Portal to Texas History to show how the UNT Campus has changed since 1890. This project is a 2015 collaboration by former UNT GIS Librarian, Douglas Burns, and then-graduate student, Arya Hackney.
• City of Denton Interactive Maps: Explore Denton city and county information
• Hurricane Ian Damage Mapper: This map is designed to display damage caused by Hurricane Ian from cell phones, drones, and satellite imagery (from the site).
• COVID-19 Dashboard: an on-going project by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU).
• GIS to 3-D imaging: a blog post from a project at the University of Utah

For much more on GIS applications and data, see the Mapping and GIS Guide.