NOAA’s Science on a Sphere adds a new dimension to data displays

Satellites and computer simulations create thousands of datasets that describe phenomena on the Earth, such as images of cloud formations and land features, models of climate change, and graphic depictions of ocean currents and atmospheric conditions. But typical 2-D displays of such data distort the images on a flat surface.

That bothered Alexander MacDonald of the National Oceanic and Atmospheric Administration, one of the primary producers of such data.


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Science on a Sphere gains international appeal


“As scientists we should be looking at the Earth as it really is,” said MacDonald, director of NOAA’s Forecast Systems Laboratory in Boulder, Col. “I wondered: Why don’t we display things on the full Earth?”

At home, using a beach ball and a couple of video projectors, he rigged up a garage prototype of a spherical movie screen on which data gathered from the Earth’s globe could be rendered in the same format.

“It looked pretty good,” he said.

After years of software development and material testing, NOAA’s Science on a Sphere moved out of the garage and debuted in 2002 at Broomfield Heights Middle School in Colorado. As of this writing, there are about 35 of the spheres installed in museums, science centers, research facilities and schools around the world, with as many as 50 expected by the end of the year.

“We’re getting a lot of international orders,” MacDonald said.

“It’s a big white ball, and it uses a system of four projectors,” said Miles Roberts, curator of the National Zoo’s Amazonia Science Gallery in Washington, which installed Science on a Sphere in February. “It’s a very powerful teaching tool,” he said, and the zoo is planning several teacher training programs using the sphere this summer.

A series of computers feeds data to projectors, which display the images on a sphere 68 inches in diameter, typically in a format of 4,000 by 2,000 pixels. The large scale globe can realistically depict ocean currents, atmospheric temperatures, population trends and other data. In the seven years since its debut, Science on a Sphere has been patented — and the name has been trademarked — and its software has been upgraded to take advantage of advances in computing power. Today, in addition to full-motion video, the display image can be re-rendered in real time, allowing a user to shift the point of view on the globe using a Wii remote wireless controller so that you can see ice pack conditions at the north and south poles or watch the spread of the 2004 Indian Ocean Tsunami

“We couldn’t do that until three years ago,” MacDonald said.

The latest innovation is SphereCasting, a scheme to network stand-alone spheres via the Internet so that people can give synchronized presentations around the world, controlled from a central location.That still is in testing phase, MacDonald said. “We have done several that prove you can do it.”

The system was developed in NOAA’s Forecast Systems Laboratory, where a graphics team led by David Himes was assembled to write the software.

MacDonald has a doctorate in meteorology with computer science as an allied field. “I like software,” he said. “I was always interested in graphics.” But he decided to take advantage of the graphics expertise already available in the forecast lab. MacDonald roughed out requirements for a system that would distribute data to multiple projectors, perfectly synchronize displays and format images so that they remain in focus on a convex surface and merge into one another without visible seams.

The task took a three-man team about three years to initially complete. The software is written in C++, and despite the complexity of the task, it consists of about 100,000 lines of code, considerably smaller than a typical operating system. It runs on a “pretty hot Linux box,” he said.

Five different materials were tested for the globe. At 245 pounds, a six-foot fiberglass globe was too heavy to be practical and plastic stretched under its own weight when suspended, elongating the globe. “We ended up with carbon fiber,” MacDonald said.

The cost of a Science on a Sphere unit is about $165,000. Each owner pays for software and hardware, although NOAA’s Office of Education has provided more than $3.7 million to assist with developing exhibits and creating content. The owners purchase their own computers and projectors. NOAA loads the software, provides a crew to install the system and offers support for three years.

“They have created a system that is as maintenance- and trouble-free as possible,” the National Zoo’s Roberts said.

The software is written to support any number of projectors, but the zoo’s setup is typical, following NOAA’s recommendations for equipment. It uses four high-end Sony projectors that provide a resolution of 72 dots per inch on the sphere. These are aligned every morning to keep the images in sync. Each projector is controlled by a Dell Precision T3400 workstation running Red Hat Linux. A fifth T3400 hosts the content for the sphere and controls the other four computers. There is a Bluetooth connection on the control computer for the Wii Remote.

There are about 250 datasets now available for display on the sphere, said Kairo Vivas, coordinator of the Amazonia Science Gallery, who runs the sphere on most days. Many of those have been produced from NOAA and NASA Earth observation programs. Some are compiled from satellite images, others are computer simulations, and others are visualizations of data gathered from surface or satellite sensors. Sphere owners also can create their own programs, which can be made available to other spheres on a Web portal.

“Very little programming is required to use this,” Roberts said. “We’re the only zoo that has one of these. What we are able to contribute is data on wildlife,” including landscape, ecology and habitat ranges.

The zoo has developed a playlist of popular datasets that run more or less continuously on the Amazonia sphere. As visitors ask questions or request other displays, Vivas, using the Wii Remote, presents the data and shifts the globe’s orientation to answer questions.

Some of the popular displays for the Sphere of Science are:

  • The “Blue Marble,” a static composite satellite image of the Earth created in 2001.
  • Weather satellite images showing the entire 2005 hurricane season, which included Katrina and was the most active on record.
  • A visualization of global ocean currents, showing the speed and movement of water.
  • A visualization of sea surface temperatures.
  • A visualization of worldwide wave activity from the 2004 tsunami, as detected by satellites.
  • Distribution of particulate pollutants in the atmosphere.
  • A composite image of the Earth at night, showing only illumination from electric lights.
  • A model showing global temperature changes from {tk: the year?} 1800 projected through 2300.
  • Global air traffic during a 24-hour period gathered from transponder data from commercial aircraft.
  • The solar surface with sunspot activity.
  • The surfaces of other planets and moons in the solar system.

Science on a Sphere is being commercialized by Global Imagination, which offers what it calls Magic Planet in a variety of sizes, from portable 16-inch globes with an internal projector that can be run from a laptop or DVD player to 60-inch and larger globes using external projection systems similar to what NOAA uses.

There also is talk of military applications for the sphere, such as showing deployments and other activities around the world. But research and education remains MacDonald’s primary focus for the systems.

“There is no better way to look at that data than on a sphere,” he said.

About the Author

William Jackson is freelance writer and the author of the CyberEye blog.

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