What is a Geographic Information System (GIS)?
A geographic information system (GIS) combines mapping and databases to allow a wide array of uses. In its simplest form, GIS can be used to create a custom map; in its more complex forms, GIS brings together many different kinds of data with spatial and database analysis tools. This enables people to more easily see, analyze, and understand patterns and relationships.
A GIS consists of:
- Data –– the geographical information that describes features and activities in the area of interest. Modern GIS uses digital data. The two main types of GIS data are:
- Raster data represents geographic data as a matrix of cells that each contains an attribute value. For example, we often represent imagery, land cover, and population density data as raster data.
- Vector data uses points, lines, and polygons to depict features. For example, fire hydrants, contours, and administrative boundaries are often displayed as vector data.
Computer Hardware –– GIS uses a wide array of computer hardware, from desktop computers for end users, high speed servers for data storage and distribution, and mobile devices for data collection.
Computer Software –– GIS software displays data in numerous ways while also providing diverse tools to process and analyze combinations of data. Various forms of GIS software can be applications on desktop PCs and mobile devices and in web browsers.
How is GIS used?
GIS is used by many State and Federal agencies for emergency response planning, business development, real property tax administration and analysis, transportation planning and analysis, wildlife and natural resource analysis, health care (disease studies), and school district (school aid distribution) and political boundary mapping.
Many local governments use GIS for similar tasks, as well as for criminal investigations, 911 administration, tax mapping, analysis of census data, development planning and engineering.
GIS is also used in the private and not-for-profit sectors in many ways, such as tracking utility service status and evaluating properties for potential development or conservation.
Where can I learn more about using GIS?
More on GIS can be found here:
Introduction to GIS (from QGIS)
National Geographic Education: Geographic Information Systems