The Geospatial Revolution Project, from WPSU Penn State public broadcasting shares how GIS developed as a product of centuries of mapmaking and 20th-century, computer-based technology. Geography has come a long way from the days of Babylonian maps on clay tablets. Mapping on foot was followed by aerial photographs, which gave way to satellite data. Out of these was born the Geographic Information System (GIS), which makes the viewer the center of the map.