Content area
Full Text
To define Geographic Information Systems (GIS), it is helpful to start with desktop mapping applications. Many people have used Web sites such as MapQuest (http://www.mapquest. com/) or MapsOnUs (http://www. mapsonus.com/). At these sites, users can enter an address and receive a map showing where that address is located, or enter a point of origin and a point of destination and receive driving instructions for the best route.
Behind these sites is a database of geographic information connected to a database of feature or attribute information, both of which are connected to a Web server. This combination allows users to retrieve information that creates maps on the fly without a lot of previous experience.
Geographic Information Systems enable users to take the same kind of digital representation of a geographic area, combine it with statistical or other feature information about that area, and conduct spatial analyses. This article provides an introduction to GIS technology and its applications, and describes a few examples of how GIS is used in libraries and other informationbased organizations.
WHAT IS GIS?
Geographic Information Systems are hardware, software, and digital geospatial data combined to provide mapping capabilities, databases of geographic and feature information, and spatial analysis. This combination offers a dynamic way of looking at a situation. The mapping provides a visual display of an area, such as the city of Chicago. The feature information tells you about that area-for example, where the bike paths are located throughout the city. The spatial analysis lets you look at an area in relation to other areas, in relation to changes over time, and in relation to various factors. For example, users could look at the distribution of bike paths in the city of Chicago over a 20-year period to study the location of those bike paths in relation to new road construction.
Maps provide a very powerful visual display of information, allowing users to comprehend in a few minutes a vast amount of data that might have taken several pages of text to explain. For example, a map of crime statistics in an area and how those occurrences have changed over the last ten years conveys a great deal of complex information. GIS takes that information and compares it to real estate values for...