GIS (Geographic Information System)

A Geographic Information System (GIS) is an information system that analyzes, inputs, manipulates, outputs, retrieves, and stores spatial data. GIS is mostly used by governments; large corporations; and engineering and GIS consulting firms for land, natural resources, transportation, environmental, and urban planning and management.
Some people use the terms digital map and GIS interchangeably. This really isn’t correct. GIS isn’t just about making maps. GIS involves using computers and special software to help people make decisions by using spatial data. Distinguishing between consumer mapping programs and GIS programs is important:

• GIS software, which is sold primarily to governments, corporations, and consulting firms, is flexible, powerful, and relatively expensive.
• Consumer mapping programs target the needs of average computer users. These programs are much more limited in scope and functionality — and a lot less expensive — than GIS programs.

GIS software typically has a steep learning curve; you can earn advanced degrees in GIS. Consumer mapping programs can mostly be used right out of the box and can be mastered in a relatively short period of time. A typical consumer mapping program is a road map program that costs about $30 and provides exact routing directions to get from one location to another. This isn’t a static map because it has underlying data (such as street names, distances, and gas stations), which can lead you to think it’s a GIS program. Not so. A true GIS program has built-in precision tools that can (for example) let you input data about traffic flow and vehicle speeds, and then display every street where traffic volume exceeds 500 cars per hour and vehicle speeds are .5 miles an hour over the speed limit. The price tag for such a GIS program would be at least $1,000, not to mention the costs of training people to use it and gathering all the traffic data to input into the system.

Of course, if you have a burning need for high-end precision and complexity, it’s still possible to get into GIS on the cheap. A growing community is developing open source and free GIS programs. Although many of these programs lack the polish of a commercial product, they do get the job done. The http:// opensourcegis.org and www.freegis.org Web sites are two excellent resources for finding out more about free GIS programs.