Until the advent of GIS, analog maps (typically presented as paper maps) served as the basic means of storing and displaying geographic data. The primary limitation lay in the fact that only a small portion of the data could be manipulated at one time; making manipulation a very time consuming process. As the use of digital storage for geographic data became more common, manipulation and retrieval of the data became faster and easier to handle. The problem of relating different geographic features to each other, however, still remained.
"Map Algebra"is the process which finally brought the potential of digital geographic data into realization. As its name suggests, Map Algebra is the process of manipulating geographic features through the addition, subtraction, and manipulation of each feature's assigned value. Map Algebra is the foundation of GIS allowing the separation, combination and analysis of distinct geographic entities.
The quality distinguishing a Geographic Information System from graphic, design, and data base systems is its ability to analyze and model data in a spatial context. The ability of a GIS to manipulate data from specific geographic locations (Click here to access a program that demonstrates this) makes it possible to create a realistic perspective of the world and the opportunity to view the effects of future actions. This unique ability provides scientists, regional planners, and resource manages the opportunity to distill and combine large sets of spatial data into useful information, offering new perspectives and fresh approaches to problem solving.
A GIS is composed of discrete but interacting components. The critical component of a GIS is a competent human analyst. The analyst is responsible for developing a careful set of procedures that outline a mission, evaluate data needs, and successfully capitalize on the abilities of the hardware and software.
history.html
Institute of Water Research, Michigan
State University
Last Revision: February 22, 1997