Perpetual Oceans, a NASA Visualization Designed for the Masses

by   |   November 1, 2012 6:42 pm   |   0 Comments

Some visualizations beguile us with their beauty, but be warned: making them takes a bite out of time.

A case in point is the Perpetual Oceans video posted by NASA on social media in March. Though the animation, which shows the flow of the oceans currents over June 2005 to December 2007, was more than two years old, once it landed on Facebook it swept around the Web. The swirls of the ocean currents drew comparisons to Van Gogh’s The Starry Night, and praise for its “quite spectacular” and “mesmerizing” flow. (The swirls, by the way, are not hurricanes – you can see Hurricane Katrina and other major storms as quick shimmers.)

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The ability to capture the public’s attention was the point. But be warned: most companies will find they don’t want to put in the effort it takes to make such a lovely video. That’s straight from the mouth of Horace G. Mitchell, director of NASA’s Scientific Visualization Studio Group at the Goddard Space Flight Center in Greenbelt, Md.

“We have agencies come in and say ‘we want to do this, too,’ and they listen to us and go away shaking their heads. It’s expensive and requires expertise,” he says.

The actual tools NASA uses, like Maya, an animation design tool from Autodesk, and Renderman, Pixar’s software for bringing those animations to life, aren’t difficult to learn, Mitchell says. An individual could learn the tools and create a similar visualization. “But as soon as you start doing it with a lot of deadlines and you have enough people doing it, you need computer clusters to create the renderings, and you want to do it better and better.”

Designers Who Support Research Scientists
NASA visualization designers have a different mission than those in business, Mitchell says. Business managers are looking for visualizations to bring them insights to guide decision-making. They are not looking to convey important scientific concepts to share research findings with a broad audience, and they don’t usually need to make something look so realistic.

Mitchell’s team is a bridge to the public’s understanding of researchers’ findings. He notes that he came to NASA in 1991 thinking he was going to help scientists understand their data through visualizations. Instead, his 12-person team is largely engaged in making the data clear for the general public.

“Scientists don’t go to someone else to say, ‘I need to understand this, can you visualize it for me?’” says Mitchell. At the same time, they don’t do the best job of helping the general public understand their work. Part of NASA’s mission is to present its research in a form that the public can understand.

So Mitchell’s group pulled in some funding from NASA to work on that. The topic of the visualizations has changed over the years: where it once worked on lots of visuals of the ozone hole in the atmosphere, now they tend more to being visuals of shrinking sea ice.

Mitchell says the Perpetual Oceans video required three steps: generating data, doing a pseudo simulation of the data using virtual particles, and then visualizing it into movie form.

Ocean Data from Sensors and Satellites
The data includes things like wind velocity, current speed, water density, salinity levels and ocean temperature, readings captured every six hours from satellites and ocean-based sensors since 1992.  NASA’s scientists then can calculate the motion of a current from these data points. The visualization uses a model called Estimating the Circulation and Climate of the Ocean (ECCO), developed by Massachusetts Institute of Technology and NASA’s Jet Propulsion Laboratory in Pasadena, Calif. The result creates “realistic descriptions of how ocean circulation evolves over time,” according to NASA. The agency says ECCO model “are among the largest computations of their kind ever undertaken,” done by high-end computing resources at NASA’s Ames Research Center in Moffett Field, Calif.

The data points are all static, so to build an accurate model of that current, Mitchell’s group uses virtual particles to show how an actual particle would follow the wind, based on what the data says. Mitchell says that using virtual particles makes NASA’s ocean visualization more true-to-life than well-regarded visualizations like the Wind Map, because they reflect changes in the continuity of flow reflected in the data.

The original visualization that became Perpetual Oceans runs 20 minutes; the version that became popularized is a three-minute slice of that longer video, shown at the top of this article.

Mitchell says it took his team about two months to do the long version, and another couple of weeks to edit it down to a shorter version, all while working on other projects.

Mitchell says NASA uses similar techniques on a great deal of its data, but again stresses that it is not focused on information visualization per se. Scientists, he says, don’t learn from the visualizations. “We won’t produce a bar chart of the highest velocity of currents in the ocean,” he says.

But what they will produce is beautiful, and “a lot of fun,” says Mitchell.

Michael Fitzgerald, an editor at LatitudeNews.com, is based in the Boston area. Follow him on Twitter at @riparian.

 

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