A GIS is a system designed for displaying, querying, analyzing, modifying, and storing spatial data -- information about places on the planet. This system uses the power of the computer to answer geographic questions by arranging and displaying all kinds of data about places in a variety of ways (maps, charts, graphs, and tables) based on questions and decisions made by people.
A GIS is composed of four components...
Computer hardware that is fast and has plenty of memory and storage
Software tools that can handle complex mapping and data analysis operations
Geographic data about where things are (such as in a country) and what it is like there (such as a large population)
A thinking explorer who is interested in exploring geographic questions and using the other components
A way to begin understanding GIS is to think about maps. Maps are powerful tools. They help us do all kind of things. For instance...
They can tell us where something is --such as the location of Fulton County in Georgia.
They can help us visualize patterns --such as the distribution of African Americans in counties across the 48 contiguous states.
They can help us compare information across areas--such as the differences in the Gross National Product in Caribbean countries.
They can help us plan a trip or record a route --such as the general track of Columbus' voyage in 1492.
They can also help us see places beyond our immediate surroundings and our personal knowledge --such as the lay of the land around Port-au-Prince, Haiti.
Maps can help us ask and answer geographic questions. They can guide, inform, and help us make decisions. However, many of the maps we are presented with are static. On paper or in an electronic snapshot, maps can not be changed easily.
GIS, on the other hand, is dynamic and shows us more than a single map or atlas. GIS allows us to create, change, and analyze multiple displays on the fly. GIS is very good at addressing issues such as:
· "What if..,"
· "I want to add new data..,"
· "Let's zoom in...,"
· "Our map legend ought to look like..."
Lastly, here's one other way to help you visualize what GIS is. GIS is a mix of information about the real world (such as population, highways, rivers, and elevation).
These data are represented by points (like the location of fire hydrants in Atlanta or state capitals across the country), lines (such as Interstate 70 or the Mississippi River), and areas/polygons (many-sided chunks of land such as New Mexico, the Superior National Forest, or Aroostook County, Maine).
These are layers of information that span a range of geographies (for instance, from areas as large and remote as the Antarctic, down to a single city block in Hapeville, Georgia).
Most importantly, all of these geographic and data pieces are tied together and can be explored with a computer and interactive software directed by geographically inquiring minds.