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What exactly is GIS?

Examining things from a "spatial" perspective
    The use of geographic information systems (GIS) to solve problems, support decisions, and better understand Earth's processes is rapidly becoming commonplace in private industry, governmental organizations, and educational institutions.  As a result, there is an ever-increasing demand for professionals equipped with the knowledge and skills necessary to use GIS in a wide-range of disciplines.
    A GIS is a specialized type of information system that enables people to study the location and relationships among events, activities, and things on the Earth's surface. Examining things from a spatial perspective enables us to not only see where things happen, but also answer the questions of how and why.
    For example, GIS is commonly used by:
  • Environmentalists to monitor changes to sensitive habitats or the effects of pollution
  • Biologists to track animal movements and map invasive species of vegetation
  • Geologists to search for minerals and to assess potential damage from earthquakes
  • Foresters to inventory forest resources and determine clearcut size and location
  • Businesses to pick locations for new stores and to map customer-spending trends
  • Emergency services for 911 systems and planning for emergencies and evacuations
  • Electrical, gas, and utility companies to keep track of distribution networks
  • Real estate appraisers to location ownership and tax information for parcels of land
  • Police departments to track crime trends and target enforcement
    To see more examples of how professionals are using GIS to solve real-world problems in a variety of fields, visit Esri Industries.
The components of a GIS
    Many people think of GIS as simply a software program for making maps.  However, this is only one piece of the "GIS pie".  As stated earlier, GIS is a specialized type of information system consisting of many components.  These components, when working together in harmony, enable people to collect, manage, analyze, and present spatial information needed to solve problems and support decisions.  Below is a list of the components central in any GIS:
  • Hardware - these are the physical components of the system. Computers, servers, printers, the network, digitizing tablets, scanners, cameras, GPS receivers, satellites, etc.  They provide the tools required for spatial data input (acquisition, capture, collection), computing (storage, retrieval, processing), and output (display, print, communicate).
  • Software - software programs specifically designed to handle spatial data.  The key features of any GIS application are data capture and query, spatial analysis and modelling, cartographic production, spatial data management, and application development.  Some of the more popular software packages include ArcGIS, Geomatica, IDRISI, MapInfo, and Maptitude.

  • Spatial data - without question the most important part of a GIS.  Spatial data can be defined as "information about the locations and shapes of geographic features and the relationships between them" (Esri, 2012).  Data is typically divided into two types, features (coordinates) and attributes (characteristics) and modeled using either the vector or raster data model.

  • Methods - although critical within a GIS, this component is often overlooked.  Methods such as guidelines, specifications, standards, and procedures can be thought of as well-designed plans and application specific rules describing how the technology is applied.  For real-world examples of appropriate use of GIS, visit Esri's "best practices".

  • People - a GIS is useless without people that know how to use it.  Users can be divided into three categories; those who use GIS to make maps (users), those who use GIS to analyze data (analysts), and those who make GIS work (developers).  Examples of job titles include GIS Technicians, GIS Analysts, GIS Specialists, GIS Managers, and GIS Developers.
Defining GIS
    So, what's the definition of GIS.  This sounds like a simple question, but the answer is not so simple.  Definitions tend to vary depending on who you ask and at what level of detail you wish to achieve.  Some are broad and only address the technology, while others are more precise and focus on its applications.  However, one definition that aims to fully describe the purpose and application of GIS is stated below:
  • "A system of hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modeling, and display of spatially referenced data for solving complex planning and management problems." (Rhind, D W, 1989)
Even though this particular definition doesn't specifically make mention of the "people" component, it is assumed that people are required to make this thing work.  One thing to point out however, is the emphasis on "spatially referenced data".  This is what separates GIS from other types of information systems. A GIS is uniquely designed to handle data that is tied to locations on the Earth's surface.  A variety of data formats (i.e. geodatabase, shapefiles, grids, etc.) have been developed to store spatial data and applications are programmed specifically for processing them.

Coupled with this is a GIS's ability to take this type of data and turn it into meaningful information (value-added).  To illustrate this point, consider the following.  Suppose you wanted to identify the best location for a new landfill based on variables such as slope, soils, and vegetation.  The variables themselves are simply layers of spatial data.  However, when overlaid and integrated together, they are transformed into new information.  The resultant "risk to erosion" map can be used to both make and support informed decisions.  Here's the best place and here are the places to avoid.
     The most obvious way of understanding what a GIS is capable of is looking at its applications.  Check out the videos from Penn State's Geospatial Revolution Project.  For more information about what a GIS is, the benefits of GIS, and the geographic approach, visit GIS.com.
Geospatial Revolution    
    The Geospatial Revolution Project is an integrated public service media and outreach initiative about the world of digital mapping and how it is changing the way we think, behave, and interact.  Copyright © 2010 Penn State Public Broadcasting, an outreach service of The Pennsylvania State University.  Below is the first of four episodes to air.