Professor estimates crowds with satellite image

01-21-09 Obama
President Barack Obama delivers his inaugural address at the U.S. Capitol in Washington, D.C., Tuesday, January 20, 2009. (Nancy Stone/Chicago Tribune/MCT)
Published On:
Wednesday, January 21, 2009
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An ASU journalism professor using satellite images calculated that 800,000 people attended President Barack Obama’s inauguration ceremony.

Walter Cronkite School of Journalism and Mass Communication professor Stephen Doig calculated the official inauguration crowd estimate after analyzing a GeoEye-1 satellite image shot at 11:19 a.m. from a height of 423 miles. GeoEye-1 is a military-controlled satellite.

Doig said the image was taken 40 minutes before Obama’s swearing-in, but adjusted his estimation to include people who were still coming in before the swearing-in.

“The space-based image is fascinating because all the low-level shots make you think the crowd is much larger,” Doig said. “You see the very dense clots of people in front of the Jumbotrons but then the wide open spaces elsewhere.”

Doig originally tried to calculate the crowd size through a camera hanging from a balloon 700 feet off the ground.

The balloon was operated from the ground by a company called Digital Design & Imaging Service. The Virginia-based company specializes in taking scenic pictures for planning projects of architects and developers.

Company president Curt Westergard asked Doig to calculate the amount of people at the inauguration from an image the camera took.

The camera initially went up at 4:50 a.m. and took its last photo at 7:30 a.m. MST.

Westergard said the camera was intended to take a picture two hours before the inauguration began, but because of George Bush’s early arrival and temporary flight restrictions, officials had the balloon come down earlier than expected.

Doig said one of the issues with the camera was the clarity of the vantage point. He said that is the reason why he was unable to calculate the crowd size.

“It was a beautiful photo but useless for crowd counting because it was not a clear photo,” Doig said.

Jody Brannon, national director of the Carnegie-Knight News21 Journalism Initiative, said technology has become a tool to help journalists report fairly and responsibly.

“For this historic event, not only is technology now available to help with accuracy, but Steve is a specialist experienced in reporting on crowds,” Brannon said in an e-mail. “So it’s a double-win to help chronicle history with great precision.”

Dan Gillmor, director of the Knight Center for Digital Media Entrepreneurship, said Doig’s involvement in measuring the crowd size is significant.

“Steve is one of the real stars in understanding how data and journalism fit together,” Gillmor said in an e-mail. “So it makes perfect sense for him to be involved with this.”

Gillmor said aerial imagery has become a useful tool when making crowd estimates.

“In the past, we’ve had deliberate over- and under estimating of crowds to fit political agendas,” Gillmor said. “If technology can help us be more accurate, all the better.”

Reach the reporter at griselda.nevarez@asu.edu.