What is a GIS?

"GIS is an integrated system of computer hardware, software, and trained personnel linking topographic, demographic, utility, facility, image and other resource data that is geographically referenced." - NASA

This is probably the most asked question posed to those in the Geographic Information Systems (GIS) field and is probably the hardest to answer in a succinct and clear manner.

A Geographic Information System (GIS) is a modern term that refers to a system of database that can be linked to a digital map. In the early days of map making, information included by cartographers were limited by the space of their paper maps. Only so much information could be printed onto a piece of paper. You either must have a very large piece of paper or a very fine tip pen to write very small letters to include all the geographic information. Data on these analog maps were also difficult to update because of the time and labor needed in drawing and data gathering. With the advent of the digital era, the amount of data that a computer generated map may contain is now limited by the storage capabilities of today's computers. Drawings on maps need not be updated regularly since terrain features generally remain the same over periods of years. It was only the information that are linked to the map that requires constant updating. Digital maps today do not just contain road lines and city capitals. They can be linked and cross-referenced to a variety of databases that contain information needed by different fields of endeavors.

The capabilities of GIS are a far cry from the simple beginnings of computer cartography. At the simplest level, GIS can be thought of as a high-tech equivalent of a map. However, not only can paper maps be produced far quicker and more efficiently, the storage of data in an easily accessible digital format enables complex analysis and modeling not previously possible. The reach of GIS expands into all disciplines and has been used for such widely ranged problems as prioritizing sensitive species habitat to determining optimal real estate locations for new businesses.

The key word to this technology is Geography - this usually means that the data (or at least some proportion of the data) is spatial, in other words, data that is in some way referenced to locations on the earth. Coupled with this data is usually data known as attribute data. Attribute data generally defined as additional information, which can then be tied to spatial data. An example of this would be schools. The actual location of the schools is the spatial data. Additional data such as the school name, level of education taught, school capacity would make up the attribute data. It is the partnership of these two data types that enables GIS to be such an effective problem solving tool.

GIS operates on many levels. On the most basic level, GIS is used as computer cartography, i.e. mapping. The real power in GIS is through using spatial and statistical methods to analyze attribute and geographic information. The end result of the analysis can be derivative information, interpolated information or prioritized information.

Some practical uses of a GIS can be found in:
  • Tax, Business & Licensing Office of Local Government Units
  • Emergency Planning & Disaster Prevention
  • Real Estate Parcel Management
  • Real-Time Asset & Vehicle Tracking via GPS Navigation Equipments
  • Drainage and Flooding Analysis Using 3D Terrain Data
  • Demographic Analysis For Proper Resource Allocation
  • Marketing Analysis For Product Sales Distribution
  • Telecommunication Grid Network System Planning

Copyright of portions of this article are printed with permission from GISLounge.
Complete article can be found here.
Some images on this site are compiled from the NASA Earth Image Library.
Web images on this site are compiled from SXC website.

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