QUICK FACTS
Scientists working for the National Oceanic and Atmospheric Administration (NOAA) are using PV-WAVE to analyze and visualize solar wind outflow data. The purpose of their research is to study solar and geophysical disturbances to the sun to determine the processes by which they affect the near-Earth space environment.

THE PROBLEM
Everyone knows that the sun is overwhelmingly important to life on Earth, but few people realize how variations in the sun's energy output can adversely affect our daily lives. The sun is constantly pouring out a solar "wind" of charged particles, which vary in strength and intensity. There is a dynamic balance between this solar wind and the Earth's magnetosphere, an extended magnetic field that surrounds the Earth. This field is particularly vulnerable to solar disturbances, such as solar flares and mass ejections, which occur frequently during times of heightened sunspot activity.

Vic Pizzo, a visiting scientist with the Space Environment Laboratory (SEL) in Boulder, Colorado, one of 11 environmental research laboratories of the National Oceanic and Atmospheric Administration (NOAA), is actively studying these solar and geophysical disturbances. For example, Pizzo is currently performing computer simulations of the solar wind outflow on a Cray® super computer to develop predictions about what he expects to see from the Ulysses data. Certain subsets of the results are selected for further analysis and manipulation, then downloaded to a Hewlett-Packard® series 700 workstation. From there, Pizzo can analyze and visualize the data using PV-WAVE.

THE SOLUTION
"I used to use line plot routines to analyze my simulations," Pizzo explains, "but it was very difficult to interpret the output. Being able to visualize the data in three dimensions makes all the difference. The visualization can immediately reveal inconsistencies in the data," Pizzo reports. "This means I can use it for interactive analysis. The old-line plots were computed in batch mode -- I would set up the routine, run it, then take a look at what came out. But with PV-WAVE, I can change a parameter and immediately see the results of that change on the screen." Dynamic parameter input also lets Pizzo compare two values interactively, such as gas pressure versus magnetic field pressure. "It is very easy to perform what-if scenarios to determine if there is a distortion or discontinuity somewhere," he says. "I can use it for debugging as well as analysis of data."

This helps Pizzo study the sun's electromagnetic, particle and magnetic-field emissions and the processes by which they affect the near-Earth space environment. Pizzo uses PV-WAVE because it is well-suited to ad hoc data analysis and visualization and it includes a fourth-generation language (4GL) for creating custom functions.

PV-WAVE includes a library of high-level routines. PV-WAVE also accepts input from traditional third-generation languages so Pizzo can make use of his old routines in the new, interactive environment. "I can call the library functions for statistical, mathematical and other analysis or devise custom methods for visualizing the solar data," Pizzo explains.

"All in all, it is quite versatile, a very simple and flexible environment to work in once you understand its basic functions. PV-WAVE's standard functions include convolution, filtering and edge enhancement. There are also advanced math functions in the library, such as Bessel functions, Gaussian integrals, Fast Fourier Transforms (FFT), data point differentiation and interpolation routines. PV-WAVE is particularly good at repetitive analysis and visualization tasks, which can be triggered by macro-level programs," Pizzo says.

PV-WAVE's high-level programs execute quickly -- 250,000 floating point data values from disk to display in under three seconds is typical.

RETURN ON INVESTMENT
PV-WAVE also allows data sharing with other applications via remote procedure calls, dynamic linking, interprocess communications or subroutine calls. This makes it easy to share data from spreadsheets and database applications. "It's an array-oriented language," Pizzo says. "One nice thing about this is that you can visualize different arrays simultaneously, such as A plus B, rather than explicitly treating them element by element. Image manipulation is straightforward," Pizzo continues, "as are fundamental functions such as histogram smoothing and experimenting with different color maps. The flexibility is unlimited since you can program your own routines. Graphics utilities include 2D and 3D drawing utilities, 3D transformation utilities (scale, rotate, translate, perspective) and user-defined color tables. These utilities work in conjunction with PV-WAVE's comprehensive image processing components for defining and analyzing particular regions; zooming, panning, copying and subtraction of images; and histogram equalization. Users can take advantage of algebraic operations, geometric correction routines, polynomial warping and contour maps" Pizzo says.

Pizzo also likes the way PV-WAVE lets him shade surfaces and line plots and its ability to quickly produce publication-quality figures in PostScript, TIFF and other industry-standard output formats. "In many cases, the output from PV-WAVE is high-enough quality right off the printer for me to send to journals for publication," says Pizzo. "PV-WAVE has opened new avenues of inquiry. There is no way I could get these same insights without being able to visualize the data in this way. PV-WAVE has proven indispensable to this project," Pizzo concludes.

WORLD CLASS PRODUCTS, SERVICES, AND SUPPORT
Visual Numerics has provided technical software solutions for numerical analysis and visualization for over 30 years. The company's software products help users understand complex data from a variety of sources and build business-critical applications. Visual Numerics offers two product lines: the IMSL® Numerical Libraries for powerful mathematical and statistical analysis and the PV-WAVE® visual data analysis development environment. Visual Numerics also offers customized consulting services for applications that involve mathematical, statistical, or visual data analysis to meet today’s business analytical needs.