Mathematical and Statistical Analysis Systems

Graphics Generators

Visual Exploration Systems

Mathematical and statistical analysis systems

Production graphics environments

Animation environments

Information visualization systems

Concept mapping tools

O

X

X

O

X

X

X

X

X

X

O

O

X

X

O

O

X

X

O

X

X

X

X

O

X

X

X

X

X

X

X

X

O

X

1994), thus suggesting that GIS should be seen as media or a medium for the communication of geographic information in digital form (Sui and Goodchild, 2001). While GIS is a practical tool, GIScience, (Appendix F), addresses some fundamental questions about the relationships among data, space, and the digital world.

Whether viewed as a tool or as media, GIS can be defined as integrated software systems for the handling of geospatial information: for its acquisition, editing, storage, transformation, analysis, visualization, and indeed, virtually any task that one might want to perform with this particular information type (Figure 7.1). In the case of GIS, the information is georeferenced to locations on Earth’s curved surface. As such, GIS stand in much the same relationship to geographic information as spreadsheet packages do to tabular information, word processors to text, or statistical packages to statistical data. All of these systems rely on a basic economy of scale: once the foundation has been established for storing a particular data type, it is possible to add a vast array of functions and to serve a similarly vast array of applications with a single software package. The potential of GIS for geographic data storage, analysis, and display is described in introductory texts (Burrough and MacDonnell, 1998; Clarke, 2002, Heywood et al., 2002; Longley et al., 2001), and in more comprehensive surveys of the field (Bossler, 2001; DeMers, 2000; Longley et al., 1999).

The geospatial data that are the focus of GIS can be defined as information about places on, just above, or just below Earth’s surface. Geographic data link three elements: place, time, and attributes. For example, consider the statement that the temperature at noon on August 22, 2003, at latitude 44 degrees 58 minutes north, longitude 93 degrees 15 minutes west, was 30°C. The statement ties place and time to the attribute of atmospheric temperature. Geospatial data are acquired from a wide range of sources, including data obtained from fieldwork, maps, images of Earth obtained from satellites, and videofilm of Earth taken from low-flying aircraft.



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