This chapter provides an introductory overview of Geographic Information Systems (GIS) and graphical software, with a focus on terms and concepts relevant to their application to the modern practice of cartography. The aforementioned definition of GIS includes distinct functions: data capture, data storage, data analysis, and data display. The functions of GIS applications apply to a broad range of activities pertinent to work in cartography. A GIS provides extensive and rapid access to data, enables cartographers to perform projections or recalculate thematic data in a way appropriate for the map, and, ultimately, facilitates in producing cartographic output. The potential importance and role of computers in mapping became clear with some of the early developments in computer technology. The fundamental structure of vector graphics is reminiscent of a vector GIS. Working with graphics applications often requires extensive work with colors. Static digital maps can be stored either as a raster-based image or a vector-based image.