Introduction to Geographic Information Systems GIS
This page provides an introduction to Geographic Information Systems (GIS). Please click on the links below or scroll down the page for more information.
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Introduction to GIS
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Introduction to GIS
Geographic information (i.e.., land information, spatial information) is information that can be associated with a place name, a street address, section/township, a zip code, or coordinates of latitude and longitude.
A multitude of government functions require geographic information; at least 70 percent of all information used by local governments is geographically referenced. [1] For example, property records and assessment, planning and zoning, permit tracking, natural resource management, infrastructure and transportation management, economic development planning, and health and public safety.
All of these applications consider the location of certain features on the landscape in relation to other features. For instance, in assessment, the location of soil types relative to property parcels is considered, whereas in planning and zoning, the location of animal confinement facilities relative to residential areas might be relevant. A geographic information system (GIS) allows the user to examine and visualize these relationships. [2]
Defining GIS
A “geographic information system” (GIS) is a computer-based tool that allows you to create, manipulate, analyze, store and display information based on its location. GIS makes it possible to integrate different kinds of geographic information, such as digital maps, aerial photographs, satellite images and global positioning system data (GPS), along with associated tabular database information (e.g., ‘attributes' or characteristics about geographic features).
Using GIS, you can incorporate all of this information into a single system and execute common database operations. For example, GIS allows you to perform statistical analysis or spatial queries, to explore ‘what-if' scenarios, and to create predictive models. For example, GIS can help answer questions such as:
What exists at a given location?
Where does something occur?
What has changed since a specific point in time?
What spatial patterns exist?
What happens if…?
GIS allows you to examine and analyze geographic information at different levels of detail or from different perspectives. Then, it enables you to customize the display of your maps and analyses for presentation to particular audiences.
GIS and Coastal Management
GIS can be used for any number of coastal management applications, like improving the administration and enforcement of zoning ordinances. It can measure straight-line distances and areas, and thus determine a minimum lot width of 100 ft. and minimum lot size of 20,000 sq. ft. as often mandated in subdivision regulations. Or, GIS can also be used to generate buffers around lines or designated areas.
The benefits of taking a GIS approach to coastal management, might include: (1) the ability to model, test, and compare alternative scenarios - before the proposed strategy is imposed on the real world; (2) the ability to handle much larger data bases and to integrate and synthesize data -- leading to a more holistic and coordinated management strategies; and (3) enhanced capacity for data exchange. [3]
GIS and Decision-Making
Local government units make countless land-related decisions. As a whole, these decisions shape the way in which land is used and the built environment is managed. GIS has tremendous potential for facilitating this decision-making process and for revealing the combined effect of incremental decisions. Indeed, many have praised GIS for its ability to provide “better information” – information that is faster, cheaper, more reliable, more readily available, and more understandable – which, in turn, might lead to “better decision-making”. [4]
More or “better” information, however, will not necessarily reduce conflict in policy debates. As O'Looney (1997) cautions, “a GIS can often reveal but do nothing about underlying conflicts of interest (p. 7).” [1] Furthermore, information technologies like GIS can affect an organization's planning and problem-solving processes in contradictory ways. Elwood (2000) notes that use of these technologies can “provide new opportunities for some community members to participate, make valued and influential contributions to [an] organization's planning efforts, and enhance their capacity to take effective action on their own behalf and that of their neighborhood (p. 167).”
At the same time, however, use of information technologies also can “reinforce education and expertise barriers to participation by some residents, and diminish the authority and influence of knowledge claims based on local experience in favor of professional expertise (p. 168).” [5] Thus, it is important not to adopt an “appliance mentality” when using GIS.
Remember that successful use of GIS does not depend on technical choices alone. Organizational and institutional factors frequently are a greater barrier to successful GIS use. To make this innovation a useful component of a decision-making process, a community should carefully consider all facets of GIS implementation – technical, organizational, legal, and administrative.
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