The development of the collective geotechnologies has brought an explosion in the availability of geospatial data and, along with it, the emergence of a large and varied offering of spatial analysis tools.
      The latest wave of these visualization tools enable users to display the results of their analyses with graphical representations.
      Visualization is one of those malappropriated words that has been used in so many ways by so many people for so long that its meaning has blurred. In only a few years, the word has devolved from useful descriptor of an emerging technology to jargon to buzzword to techno-babble.
      In fact, most companies that make visualization software, call it something else just to avoid the confusion.
      In its broadest sense, any graphic display of data might be considered visualization, including the charts available in today's personal computer (PC) spread sheet programs. Certainly, geographic information systems (GIS), with their graphic representations of the real-world would seem to fulfill the meaning of visualizing information.
      But, of course, this broad a definition is what blurs the definition in the first place.

An Historical Perspective
Visualization is a relatively new computer discipline, which emerged along with experimentation in three-dimensional computer modeling.
      "In the late '80s, there was tremendous energy in formulating ideas for rendering objects in three dimensions," said Bill Cleveland, department head, Statistical Models and Methods Research for AT&T Bell Labs in Murray Hill, N.J. "The new graphics paradigm became 3-D and out of this grew the tools now called scientific visualization."
      But from Cleveland's perspective, scientific visualization should not be limited to 3-D; it's just that 3-D created the popular interest that has helped form a market for the widespread development and use of more creative data analysis tools. "Three-D is the sexy stuff," he said. "It got lots of attention." But it hardly defines the genre.
      More accurately, scientific visualization traces its roots back to research begun several decades earlier.
      "In the late '50s, early '60s, scientists began thinking a lot about how to display data to gain a better understanding," Cleveland said. "In those early days we called it graphic methods for data analysis, but I like visualization better."
      At that time, he explained, researchers were beginning to analyze data broadly, experimenting with structures that might help shed understanding. "We were developing tools for attacking data of very different and varied kinds and making sense of them."
      To Cleveland, two, three, four or ten dimensional is not the defining issue. "Visualization is any valid representation that helps you understand the structure and meaning of data," Cleveland said. "But it is more than just a bunch of tools. It is the basis for a philosophy of data analysis."

Visualization as Scientific Discipline
Cleveland and most of his contemporaries agree that visualization tools are a product of statistical/scientific research.
      A statistician by training, Cleveland is an authority on data analysis and has authored many books on the subject. He emphasized that visualization is more than pretty graphs for board-room presentations, or a representation of physical reality. When he talks about visualization, he is talking about a fundamental tool for scientific endeavor.
      From this perspective, there are three basic uses for visualization tools.
      1. Real-world representation. The first, and most basic, application would be the physical representation of the real world. This might include medical modeling, like imaging a patient's ailing heart in 3-D to determine if surgery is required, or interpreting complex remote sensing data of the earth.
      2. Analysis with a geographic element. At the next level, a spatial element may be added to an otherwise non-spatial analysis. The social scientist trying to discover a correlation between health, income and education, for example, might add geographic region as a fourth factor.
      3. Visualization of purely non-spatial data. Statistical analysis, like the performance of multi-packed digital transmissions or the effect of a new drug for the treatment of AIDS, have no spatial element, and yet displaying the data visually may present the results more clearly than numerical charts.
      "Visualization is more than the quasi-physical rendering of reality," Cleveland said. "Most data of science and technology doesn't even have an association with physical reality, but every set of data does have a graphical element."
      Applying the right visual representation improves understandability, Cleveland asserted. In scientific research you begin with a hypothesis, build a model and then test the hypothesis. Visualization tools also help the researcher confirm the validity of an assumption, establish confidence intervals and make sure the model fits the data. "If the model doesn't fit, the data just sits there without meaning," Cleveland said. At this level, visualization can help clear away the nonsense and erroneous research.

From Statistics to Earth Sciences
Within the geosciences, however, the representation of the real world and spatial relationships is a primary part of understanding.
      "Visualization tools make the most intuitive sense in the geosciences," said Dave Uhlir, product manager for Research Systems, Inc. in Boulder, Colo. "In a GIS, information is structured geographically. There is essentially no meaning to the data unless you can view it."
      While using visualization tools to plot stock market movements or socio-economic trends may be less obvious, the earth is an obvious framework for visualization.
      "This is the home of visualization," he said. "You are representing reality in a computer."
      Like Cleveland, Uhlir is careful to point out that just having a map image in a computer does not qualify as visualization. At least it must include another level of analysis. "It takes you to a level where you are not just describing objects, but what they're made of and how they relate to each other or change over time."
      With its ENVI software, which runs on workstations and Macintosh or Windows PCs, StatSci is making inroads in the Geosciences. The add-on program performs analyses on geographic and remote sensing data.
      A major problem with geospatial data today, is that there is just too much data, and it is difficult to sort it out and make sense of it. "We know the big hairy physical picture," said Loren Shure, Manager of the Application Development Group for Mathworks in Natick, Mass. "Now you can determine which variables to eliminate to simplify the analysis, and get to what is really going on in the data."
      Like many professionals in the field, Shure avoids the term visualization. Mathworks develops Matlab, which she prefers to describe as "matrix manipulation software," a core program and series of tool boxes which combine numerical processing and graphic display (another way to say visualization) capabilities, including 2-D, 3-D and time-series processing.

Science for the Masses
At ERDAS, in Atlanta, which has made geospatial analysis software for more than 20 years, visualization tools are just a natural progression of the technology-making the technology accessible to more and more people.
      "I never met a politician who could understand a contour map," declared Steve Sperry, director of desktop products for ERDAS. "People can't always relate to maps, but anyone can understand a 3-D picture."
      "Everything in our daily life is in three dimensions," added ERDAS Vice President Bruce Rado. "The use of these visualization tools brings the technology more in sync with normal life."
      Rado emphasized that 70 to 90 percent of the money spent of geotechnologies goes into data acquisition and management. "The more tools we have to analyze and use that data to greater advantage, the better our return on the investment," he said.
      "Visualization tools enable users to take the data and show it to the decision-makers in a meaningful form they can understand," he added. "Decision-makers will be more willing to trust their GIS if they can understand the results that are presented."

Burgeoning Market
For an industry with an effective life of barely a decade, visualization software has grown at a breakneck pace-all the more amazing considering the nature of the tools.
      Low-cost, powerful workstations and personal computers (PCs) have driven the market for scientific analysis and visualization to the desktop and into the hands of end users looking for practical and inexpensive ways to analyze and understand their data.
      "We're experiencing blockbuster growth in all sectors of our business," Mathwork's Shure said. "These tools have evolved to the place that user-friendly analysis applications are available at the fingertips of more and more end users. Data and analysis are becoming available to a broader group of people."
      ERDAS's Rado sees its continuing growth as a trend that has repeated itself over and over. "In the 1980s, GIS was used primarily by researchers and academics, he explained. In the 1990s, the engineers, foresters, geologists and other practical professionals are using the technology directly."
      "The technology is becoming more intuitive, more accessible," he said, "It creates a bridge between the technologist and the manager."

About the Author:
J.D. Wilson is a freelance writer in Denver, Colo., specializing in the GeoTechnologies. He may be reached at 303-751-7636.

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