Abstract
Geographic information systems (GISs) as a technology have been studied and reported extensively and, not unexpectedly, in the field of geography. The various ways of capturing spatial data, arranging attribute data into appropriate database structures, and making the resulting large data sets efficient to store and query have been extensively researched and reported (Densham, 1991). However, the geographic research community has only recently noted the need to study how GISs are used as decision tools, especially with regard to how such decision making might be related to a decision maker’s cognitive style (Mennecke, Crossland, et al., 2000). As an example, the University Consortium for Geographic Information Science called for research examining how geographic knowledge is acquired through different media and by users with different levels of experience and training (University Consortium for Geographic Information Science, 1996). Researchers in the fields of decision sciences and information systems have more recently begun to make contributions in the area of decision making with GISs. When a GIS is employed as a decision support system, in these studies the resultant system is often referred to as a spatial decision support system, or SDSS (see Crossland, 1992; Crossland, Perkins, et al., 1995; Mennecke et al., 2000). A geographic information system in its simplest form is a marriage of accurately scaled digital maps with a database. The digital maps comprise spatially referenced details such as natural elements (lakes, rivers, topographic elevation contours, etc.), manmade objects (buildings, roads, pipelines, etc.), and political boundaries (city limits, state and county lines, international boundaries, etc.). These natural elements are typically referenced, with varying degrees of precision, to latitude/longitude coordinates on the earth’s surface. It must be noted here that the degree of precision and, more importantly, differences in degrees of precision for the various elements are the subjects of much research and user consternation in applications of GISs to solving problems. The database, in turn, catalogs information about the various spatial elements (e.g., the names of rivers, names of buildings, building owner, operator of a pipeline, etc.). These descriptive entries in the database are often referred to as attributes of the various spatial elements. A GIS may be paired with the global positioning system (GPS), from which real-time, satellite-derived location information may be derived, as provided by an appropriate GPS receiver.
TopBackground
With regard to the effectiveness of decision making when using information tools, there is a relatively long history of researchers emphasizing that tools which provide graphical presentations and graphical representations of information are deserving of special note and study. For example, Ives (1982) discussed at great length the role of graphics in business information systems. He even went so far as to state, “The map, perhaps more than any other chart form, gains the most from the availability of computer graphics” (p. 16).
Several more recent studies have drawn from Image theory (Bertin, 1983) to help explain why decision makers using GISs may experience greater effectiveness in decision making. Image theory states that one graphical representation of information may be considered more efficient than another for a particular question, if that question can be answered in the mind of the decision maker in a lesser amount of time. In his Semiology of Graphics, Bertin defined image theory and put forth the constructs of images and figurations. An image is a meaningful visual form, perceptible in a minimum instant of vision. A figuration is a more complex construction comprising multiple images. Figurations are inherently less efficient than images, according to image theory. This is because the viewer is able to grasp the full informational content of an image in a brief moment of viewing it. Figurations, on the other hand, comprise multiple images which must be mentally extracted, processed, and related in the viewer’s perception. Although the informational content may be richer in a figuration, it is inherently less efficient for quick extraction of specific information.
Key Terms in this Chapter
Global Positioning System (GPS): provides real-time, satellite-derived location information based on information received by an appropriate GPS receiver. GPS is funded by and controlled by the U.S. Department of Defense (DOD). While there are many thousands of civil users of GPS worldwide, the system was designed for and is operated by the U.S. military. A GPS may be employed in the original construction of the digital map information to be stored in a GIS. Or, if the GIS is already constructed, the GPS may be employed to accurately render the position of new elements to be added to the GIS or the current position of a mobile element to be referenced against the information stored in the GIS. A good example might be a freight truck moving on a highway. The GPS receiver on the truck can derive its current latitude and longitude and then send that information to the GIS system in the truck cab, to a GIS in a central control center via radio, or to both for subsequent reporting and analysis.
Spatial Decision Support System (SDSS): typically, a geographic information system (GIS) that has been extended to provide knowledge workers with decision-making tools and support data.
Geographic Information System (GIS): a marriage of accurately scaled digital maps with a database. The digital maps comprise spatially referenced details such as natural elements (lakes, rivers, topographic elevation contours, etc.), manmade objects (buildings, roads, pipelines, etc.), and political boundaries (city limits, state and county lines, international boundaries, etc.). These natural elements are typically referenced, with varying degrees of precision, to latitude/longitude coordinates on the earth’s surface.
Image: as defined in image theory, is a meaningful visual form, perceptible in a minimum instant of vision.
Attributes: are the pieces of information contained in a GIS database that describe or detail a spatially referenced element.
Need for cognition (NFC): a measure of a person’s internal motivation to pursue and enjoy cognitive tasks and activities.
Cognitive Style: refers to enduring patterns of an individual’s cognitive functioning that remain stable across varied situations.