Geographic Information Systems

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When most people think about geography, they think: maps. From the earliest days of recorded history, human beings have made maps to display, remember, and use spatial information about the world around them.

Hard copy maps, displayed on paper for instance, have been the tools of the geographer's trade for hundreds of years. But as beautiful, interesting, and useful as they are, conventional maps do have their limitations. First, there is a limit to the amount of information they can store and the resolution with which that information can be represented. Furthermore, they are not easily updated; and information has to be retrieved by manually pulling out each individual map and examining it with the human eye.

The advent of the computer has transformed the way spatial information can be handled. Initially, the application of computers in geography was directed toward the production of maps, making them easier, cheaper, and faster to create. Soon thereafter, during the early 1960s, the emphasis shifted to the development of quantitative methods of analyzing geographic data with computers. The work of William Garrison at the UW and of Harold McCarty at the University of Iowa played an important role in that endeavor. They developed classical techniques of spatial analysis, mathematical methods, statistical methods, and of spatial comparison, network analysis and a wide variety of geographical modeling techniques, writes Roger F. Tomlinson in an historical perspective on the transition from analog to digital representations of space in The American Cartographer.footnote 1

Over the period from 1960 to 1969 came the true fusion of maps and computers: the Geographic Information System. The GIS is a computer system for assembling, storing, manipulating, and displaying geographically referenced information—that is, data referenced by location. The development of GIS technology opened up new horizons not only in geography, but in many other fields as well, such as urban planning.

Because of the powerful capabilities of computer systems, many kinds of data can be incorporated in a GIS. For example, digital satellite images can be analyzed to produce a map-like "layer" of digital information about vegetative cover. Census information, rainfall amounts, concentrations of pollutants, incidence of disease—anything that can be measured as a function of location can be displayed and analyzed. Location may be designated by x, y, and z coordinates representing latitude, longitude, and elevation. Or other measures of location can be used: zip codes, or highway mile markers, for example. Any variable that can be located spatially can be used in a GIS, and many variables can be manipulated simultaneously.

Today, the tremendous flexibility and power of GIS technology are being brought to bear on scientific investigations, resource management efforts, urban planning, and epidemiology studies, among other endeavors. For example, GIS could be used to identify wetlands that are endangered by pollution; or it might be used by emergency planners to calculate emergency response times in the event of a natural disaster.

While the transition from analog to digital cartographic representations has provided new capabilities, it also has created some difficult challenges for users. Tomlinson observed in 1988 that the ability to integrate data with a variety of formats (raster, vector, street address and tabular) from different sources, at different levels of reliability, at different scales, by different people with different skills, using different computers, in different countries, connected by communication networks, is a very real requirement in the foreseeable future. This means that geographically-referenced data interchange formats, computer communication protocols and the understanding of the relationships between data and decisions will become increasingly important.footnote 1

In response to that challenge, three major groups involving a wide spectrum of government agencies joined together beginning in the early 1980s to tackle the thorny problem of developing standards for handling and transferring spatial data. UW geography professors Timothy Nyerges and Nicholas Chrisman have been at the forefront of that effort for over 15 years. These two UW faculty members have held key leadership roles in that process, which resulted in the adoption in 1994 of a universal standard for spatial data.footnote 2

That such a large and diverse group of government agencies and universities, despite bureaucratic red tape, could arrive at a single standard is an achievement in itself; but even more important is that having such a standard, coupled with the rapid pace of development of new technologies, is fueling the rapid growth of the GIS industry. It has grown from a total of a few million dollars annually in 1982 to a multibillion-dollar-a-year business today.

Some 22 units on the UW campus are involved in some way with GIS projects, many using one of the leading computer GIS tools called ArcINFO. A notable example is the study of changes in tree cover in the city of Seattle conducted in the Remote Sensing Applications Laboratory of the College of Architecture and Urban Planning (RSAL).

RSAL was founded in 1971 by Arthur Grey of the Department of Urban Design and Planning, who was among the first to envision a broad role in urban and regional planning for the then emerging technology of remote sensing. Remote sensing refers to the observation of the earth from spacecraft and aircraft using sensing devices of various kinds, including visual, infrared, and other kinds of cameras and multispectrum scanners, to collect digital images. Geographic Information Systems provide the means to display and analyze these remote sensing data.

In 1991, Miles Logsdon, GIS instructor at the UW, working with Cliff Marks of the Seattle Planning Department, used color infrared aerial photography from 1971 and 1988 to map and analyze tree cover in the Seattle area. Miles devised innovative uses of ArcINFO to perform statistical analyses of these spatial data.

Since 1991, RSAL has worked with the King County Department of Development and Environmental Services Resource Planning Division on a county-wide inventory of land cover and changes in land cover over time. Loren Siebert of RSAL led the work on this project, which represents the first use of the SPOT satellite data, the highest resolution civilian satellite data, for urban analysis in the region. King County is using these GIS data for several purposes, including habitat analysis and study of productive forest lands in proximity to urban areas.

With funding from the Bullitt Foundation, faculty and staff of RSAL used satellite remote sensing and GIS for monitoring outcomes of Washington's Growth Management Act, in particular, to monitor the conservation of resource lands, the preservation of critical areas, and the reduction of urban sprawl.

In a fusion of GIS, Computer-Aided Design, and Virtual Reality, efforts are underway to link GIS capabilities with visualization tools to allow users to display and move around in a virtual three-dimensional representation of the GIS database. For example, city planners may be able to use their GIS systems to navigate through a "cityscape" or "regionscape" to visualize key features of the area or to evaluate different designs or options. This is the focus of the new Community and Environmental Design and Simulation Laboratory at the University of Washington. It is a partnership between the UW College of Architecture and Urban Planning and the Human Interface Technology Lab of the Washington Technology Center, known for its work in Virtual Reality. Demonstration projects using the Seattle Commons, the UW Henry Art Gallery Expansion, and a Modular Housing example were created in late 1994. In 1995, the group's key projects include developing a futuristic guest room for Westin Hotels and creating a virtual model of part of the city of Venice.

  1. "Reflections on the Revolution: The Transition from Analogue to Digital Representations of Space, 1958-1988," Roger F. Tomlinson, The American Cartographer: Journal of American Congress on Surveying and Mapping, 15(3), 249 (1988).
  2. Three distinct but related groups joined in the effort: The National Committee for Digital Cartographic Data Standards (NCDCDS), the Standards Working Group of the Federal Interagency Coordinating Committee on Digital Cartography (FICCDC-SWC) and the Digital Cartographic Data Standards Task Force (DCDSTF). [See "The Proposed Standard for Digital Cartographic Data," The American Cartographer: Journal of American Congress on Surveying and Mapping, 15(1), 11 (1988).] The first is a consortium of universities and government agencies; Nyerges serves on its steering committee and chairs its working group on data organization; Chrisman chairs its working group on data set quality. The second organization was established under the Reagan Administration to deal with eliminating duplication and waste in the development of federal digital cartographic databases and to coordinate related activities. It involves some nine government agencies including the Bureau of the Census, NASA, the Federal Aviation Administration, the U.S. Geological Service and the National Oceanic and Atmospheric Administration. The third player is a group formed in 1987 charged with melding the draft standards developed by the first two groups into a single digital cartographic data standard and to publish the merged standard, which was finally adopted in 1994.

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