How does a Geographic Information System work?
ORACLE and SQL Servers are the two main engines that store, manage and retrieve data for GIS users. Data is stored in raster or vector format. Raster data includes digital images from satellites, airplane fly-overs, and “digitized” maps and other electronically collected information. Vector data includes points, lines, and areas (polygons) that have been collected or created with a software application for display on a digital map. Many components make up the digital map, one being the spatial (geographical) reference to placement on the earth’s surface. The map is displayed based on scale and projection, according to federal or state standards. In addition to vector or raster data, attribute information referencing more detailed specifications such as names, size, common and unique identifiers. Who uses GIS? People who use GIS in their work include those in Natural Sciences, Computer Sciences, Land Surveyors and Civil Engineers. Historians and Marketing Agents use GIS for site selecti
