Drawing Conclusions

Computer Graphics Help Bring Overwhelming Data Into Focus

November 02, 1986|By Jon Van, Science writer.

A PICTURE MAY be worth a thousand words, as folk wisdom assures, but a good computer graphic should be worth at least a million numbers to a scientist.

The advent of computers has given researchers the ability to gather and utilize thousands of measurements within short periods. Calculations that took months to work out 20 years ago are accomplished within minutes, or even seconds.

This has been a great leap for science, but it also presents researchers with the potentially overwhelming problem of analyzing all these reams of data. To help keep researchers from sinking helplessly beneath a blizzard of statistical printouts, computer scientists are coming up with imaginative new ways of presenting data graphically.

They are devising visual images that convey at a glance information buried in columns of numbers. Colors, shapes and sizes are all enlisted to provide special messages to catch the scientist`s eye and to provide insight into what the experimentation and measurements may really mean.

In some cases, scientists and computer graphics experts have concluded that their technical orientation limits their ability to make full use of graphic arts. They have enlisted the aid of artists who are experts in color, design and form.

This trend toward more extensive and innovative use of graphics appears to have its greatest value when scientists seek to explain complex events with several variables. In some cases the graphics are dynamic--running like short film clips or cartoon subjects--to show how findings in a study interact with one another and change with time.

``There are some people I`ve known who can look at column after column of figures and see patterns there right away that jump out at them,`` said Donald Lewis, chairman of mathematics at the University of Michigan.

``But that isn`t true of most people, not even of most scientists. For most scientists, putting your data into a picture can be very useful.``

This can be the case even for mathematicians, Lewis said. An example of this will be displayed on the Ann Arbor campus beginning Nov. 10 when several colorful computer graphics will be shown in an exhibit sponsored by the university departments of mathematics and art as well as the German Goethe Institute.

These graphics grew out of efforts by German mathematicians to visually display a complex type of calculation known as Julia sets, which include fractals, a hot new area of research to describe complex and seemingly chaotic events in precise mathematical terms.

Originally, Lewis said, the Germans produced the images in an effort to better understand this type of calculation and how it behaved under several circumstances. Eventually, they became enchanted with the intricacies of design being produced, and continued producing the designs for the sake of their beauty.

At the University of Illinois in Urbana, scientists are being aided by an assistant professor of art and design as they seek to understand an infection that afflicts the corn borer, a moth larva that can seriously damage corn crops.

David Onstad, an ecologist, and Joe Maddox, an insect pathologist, are trying to take decades of research into a chronic infection common among corn borers and put it into the big picture that scientists call a model.

This model would describe how a parasitic infection within a population of corn borers affects the health of these insects and their ability to ravage a crop.

Artist Donna Cox has helped them construct a model view of a cornfield, with different shades of colors indicating how many healthy corn borers and how many corn borers infected with a parasitic microsporidium are present on each stalk of corn. The model helps the scientists keep track of several variables and their interactions with one another.

Cox, who readily concedes that insects aren`t normally part of her field of study, points out that sensitivity to shadings of color is vital to interpreting data presented in the model. ``You need an artist on the team to look for things that are visually interesting or unusual,`` she said.

``I may not be familiar with what something means, but I can point it out to the scientists and let them decide if it is significant.``

In the model, the greener an individual stalk in the field, the higher its population of healthy corn borers. Red is used to depict the density of infected corn borers. Green and red combine to form shades of yellow to give an overall picture of corn borer population, both healthy and infected.

The model is dynamic: It includes a different graphic for each day of the growing season. When the graphics for each day are shown on the computer screen quickly in succession, it is possible to watch the shades of color change and produce patterns reflecting the density and health of the corn borer population through the growing season.