GIS Geographic Information System

A geographic information system (GIS) is an integrated computer system that allows the storage, mapping, manipulation, and analysis of geographic or spatial data. It can present many different layers of information, all of which may be turned on or off depending on the user's needs. Several components are required for a GIS to function properly. A GIS typically consists of computer hardware, software, and the people operating the system, as well as the spatial or geographic data being manipulated.

A GIS works by storing a number of different data sets that each have geographical references. The various data for any given geographic location can then be integrated based on the user's needs. A powerful feature of GIS is that data from different sources may be combined into the same database and integrated in order to make it useful for several purposes. The U.S. Environmental Protection Agency (EPA) makes a dynamic GIS system available on its Web site that allows one to search and integrate information from several databases to create a map of pollution sources in his or her neighborhood.

Legend

I Discharges to water □ Hazardous waste I Air releases O Multiple Streets O Water bodies □ Counties

Legend

I Discharges to water □ Hazardous waste I Air releases O Multiple Streets O Water bodies □ Counties source: EPA Enviromapper.

GIS is a valuable tool that is commonly used by engineers, scientists, government officials, geographers, planners, environmental modelers, geologists, epidemiologists, and others. Professionals in these fields may use GIS on a regular basis for the analysis, mapping, and integration of geographical data. GIS incorporates geography through the review of spatial distribution, land features, and location, by referencing data such as an address, parcel identifier, or latitude/longitude. Approximately 85 to 90 percent of government agencies require the evaluation of geographic data and use of a GIS. Problems related to location, proximity, trends, and patterns are typically addressed by using a GIS. It also has modeling capabilities that allow specific scenarios and situations to be evaluated and used in decision-making processes.

Examples of GIS applications in state and local government agencies include land records management, land use planning, scientific/environmental investigations, infrastructure management, and natural resources planning and management. GIS is an extremely valuable analytical tool for professionals, providing support for decision-making processes, such as determining if a site is suitable for a future landfill, calculating the soil erosion potential in a specific region, or determining the best location for remediation treatment systems for contaminated groundwater plumes. GIS is frequently used by environmental engineers and other professionals to produce and maintain maps for sites they may be working on, watershed analyses, hydrologic studies, and many other applications.

Bibliography

Fairchild, Michael F.; Parks, Bradley O.; and Steyaert, Louis T. (1993). Environmental Modeling with GIS. New York: Oxford University Press.

Internet Resources

GeoCommunity. "GIS Data Depot." Available from http://www.gisdatadepot.com.

"National Center for Geographic Information & Analysis Core Curriculum in Geo-science." Available from http://www.ncgia.ucsb.edu/education.

U.S. Department of the Interior, U.S. Geological Survey Web site. Available from http://www.usgs.gov/research.

U.S. Environmental Protection Agency. "Enviromapper." Available from http:// www.epa.gov/enviro.

Margrit von Braun and Deena Lilya

LEADING COAL-BURNING STATES FOR ELECTRIC POWER GENERATION IN THE UNITED STATES

Rank

State Use

(million tons)

l

Texas

99.7

2

Indiana

59.5

S

Ohio

55.9

4

Pennsylvania

52.l

5

Illinois

4e.e

e

Kentucky

40.2

7

Missouri

S7.S

8

West Virginia

S7.0

9

Alabama

S5.e

l0

Michigan

SS.7

ll

Georgia

SS.5

l2

North Carolina

29.9

lS

Florida

29.9

l4

Wyoming

2e.5

l5

Tennessee

2e.l

le

North Dakota

25.l

Other States

S22.4

Total

990.966

source: Adapted from U.S. Department of Energy.

Electric Power Annual 2000, vol.

1. Available from

http://www.eia.doe.gov/cneaf/electricity/epavl.

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