Geographic Information Systems: An Overview

What are Geographic Information Systems?

A geographic information system (GIS) is a computer system capable of capturing, storing, manipulating, and displaying spatially referenced information. GIS is a tool for planning and decision making processes. GIS is used in a wide range of applications including urban and regional planning, agriculture, emergency response systems, and natural resource management.

GIS enables users to produce high quality maps at any scale, to store and maintain a large quantity of geographically related information, to visualize and simplify complex data, and to create new data from existing data. The most powerful aspect of a GIS is that it allows users to perform complex analyses by linking data layers and overlaying different data sets to get a spatial perspective.

What are the Parts of a Geographic Information System?

Hardware

Hardware is the computer system (including scanners, digitizers, printers, and plotters) on which software operates. In the past, GIS has only been accessible to those with high end computer systems, but with the advent of affordable desktop GIS packages, GIS is becoming accessible to more and more users.

Components of a GIS

Software

GIS software includes the tools used to store, analyze, and display geographic information. All major GIS packages have a data structure with a spatial representation of the data and links to attributes that are stored in a database. Many desktop packages also provide an easy-to-use interface for data query and spatial manipulation tools such as panning and zooming.

Data

A fundamental component of a GIS is the data. Geographic data are available through private companies, universities, government agencies, and non-profit organizations. Data can often be obtained free over the Internet or for a fee through commercial providers. It is important to note the source of all data sets and keep in mind issues such as scale, resolution, map projection, and date. These elements should be recorded in a metadata record, which documents different aspects of a data set, including source, projection, and contact information.

People

GIS technology is of limited value without the people who understand GIS concepts and how to apply the technology to real world problems. GIS is a tool that allows users to make maps for visualization purposes. The greatest benefits are realized through GIS analytical capabilities. Organizations with successful GIS groups have well trained personnel with a variety of applied backgrounds.

Applications

Applications of geographic information to real world problem solving is the crux of any GIS. Whether the application be simple data tracking and storage or complex multidimensional analysis, a GIS should be designed with the potential applications in mind. This technology can be an important tool for coastal resource managers. Applications could include water quality monitoring, mapping of coral reefs or oyster beds, shoreline monitoring, land use planning, and hazard mitigation.

What are Common Data Formats?

Three Vector GIS Data Types

There are a number of different data formats that can be imported into a GIS. The most common form of data is vector data, which includes point, line, and polygon data. Examples of each of these types of data can be seen above.

Vector data have attributes associated with them. The attributes can provide information about ownership, polygon names, collection dates, sources, special codes, or any other information that is pertinent to the spatial data. The attributes are stored in a database file and are linked to the vector information. With a GIS, users can access the attributes to perform analyses and query the vector data.

Attributes for the States GIS File Include
State_name, Sub_region, and State_abbreviation.

Recently, remote sensing data have become a data source valued by many GIS users. Many GIS software packages allow users to import and view raster data, such as aerial photography and satellite imagery. To learn more about remote sensing data, click here.

Return to Top | Return to Main Menu