Managing by the Map

Article excerpt

Increasingly-sophisticated GIS software is enabling businesses, government, and other agencies to interpret data in promising new ways.

Attend a seminar or read an article on modern marketing research, and one invariably encounters the term "GIS."

Geographic Information Systems (GIS), one of the most important tools in this age of "niche" marketing, has significant applications in a wide variety of industries. In fact, GIS has become a buzz word that represents to many a panacea to problem solving and decision making in marketing, resource management, planning, and environmental monitoring.

However, like most tools, GIS technology is only as good as the person using it, just as merely using a word processing software such as WordPerfect does not necessarily make one an accomplished writer. This is a pitfall too often overlooked by those who are fervently trying to embrace the technology. Effective use of GIS requires an understanding of the fundamental concepts of geographic data, map coordinate systems and registration, data integrity and accuracy, overlay analysis, and database manipulation. Applying GIS therefore involves more than merely investing in the necessary hardware/software system, and mastery of GIS software should not be equated with expertise in GIS. This article is intended to provide the reader with an understanding of the technology and demonstrate its potential as a valuable tool for business applications.

The concept of geographic information systems (GIS) evolved in the late 1950s from the traditional manual procedures for registering and overlaying individual layers of maps onto one another (giving rise to the term "light-table gymnastics.") This innovative use of maps as an analytical tool provided an entirely new facet in map usage, from mere physical description of geographic phenomena to spatial modeling applications (Berry, 1987; Parker, 1987).

Today, the evolution of GIS technology is intimately linked to the advent and development of computer technology. In its present form, GIS technology integrates spatial modeling, database management, and computer graphics in a hardware/software system for managing and manipulating geographic data. Typical GIS software, therefore, will provide the mechanisms to capture, encode, edit, analyze, compose, and display spatial data organized as map layers in a GIS database. In effect, these functions are categorized [ILLUSTRATION FOR FIGURE 1 OMITTED] as the four major components of a GIS: data input, data analysis, data management, and data output (Aronoff, 1989; Star and Estes, 1990).

At the core, a database

The key to proper application of GIS technology is the database. A GIS application today most probably will incorporate a relational database management system for the manipulation of feature attribute information.

A GIS database contains map layers representing geographic themes organized in a digital format (Marble and Peuquet, 1983). These map layers, which are geocoded to a standard coordinate system such as the Universal Transverse Mercator (UTM) or State Plane Coordinate systems in use today, may be conceptualized [ILLUSTRATION FOR FIGURE 2 OMITTED] as a stack of floating maps tied to a common map base (Avery and Berlin, 1992). Each map layer can be independently accessed. When combined, information and related attributes from individual layers can be referenced to one another from a spatial standpoint.

In addition to the map layers, a GIS database also will include a data file or files containing attribute information about features indicated on each map layer and stored in a database file. For example, the data for a map layer of the road network of Shelby County may include such information as road name, road type, physical distance, class type, and address range. Through a relational database management system, the attribute information for each map feature in the database can be directly accessed as part of the input for analysis. …