It takes literally seconds to find baseless rumor-mongering in the political blogosphere.  It's like an updated version of the old saying about how to tell when a lawyer is lying:  How can you tell when a political blogger is spreading misinformation?  Answer:  He's posting on his blog.

The Virginian pointed out (by which I mean copied-and-pasted) an article from NewsBusters:

I doubt it would surprise anyone here that the media would go to their best lengths to over-estimate the number of people at Obama's inauguration. But just how far? Try a million people.

And this, too, from a place called Moonbattery:

Professor Stephen Doig of Arizona State scientifically estimated the size of the Moonbat Messiah's inauguration crowd at 800,000. But Obama's toadies in the mainstream media don't need no stinking science. (emphasis mine)

NewsBusters is a widely-cited blog -- by conservatives, strangely -- dedicated to "Exposing & Combating Liberal Media Bias."  It's not made clear exactly how they go about doing that, but one can assume that "making stuff up" isn't outside of their ethical restraints.  How can you tell?  For one thing, their .org site is plastered with in-your-face advertising (including the paradoxically ubiquitous ads containing what look like malnourished underage girls modeling anti-liberal T-shirts in enticing poses).  For another, consider the reasoned analysis leading to the bold claim above:

ASU journalism professor Stephen Doig took it to the satellite image to get an accurate count of the crowd. His tally, after even [sic] accounting for those still in route to the event: 800,000.

Well that's certainly an ironclad assertion.  Because everyone knows that when you want to analyze satellite imagery, the first place you should go is the Walter Cronkite School of Journalism and Mass Communication.  What, you didn't know that?

Okay, so NewsBusters probably just didn't feel the need to clutter their article with Professor Doig's scientific methodology or credentials, perhaps concluding it would be too complex for their target audience to follow.  Still, I'm a pretty smart guy with some interest and experience in image processing; I was curious to see how you compute the number of people at an inauguration from a satellite photo.  No problem, we'll just click on over to the source article on asuwebdevil.com ("ASU's online news source") to find out how the good professor arrived at his numbers:

Doig said the [satellite] 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.”

Um.  Okay.  So his methodology is to, you know, kind of look at the wide open spaces.

I guess asuwebdevil.com didn't think it was necessary to verify the professor's claim, either -- perhaps they were only obliged to "report" what he told them.  Thankfully, in this case, they went the extra mile and contacted Dan Gillmor (described as "director of the Knight Center for Digital Media Entrepreneurship" in the article, but who also happens to be "Professor of Digital Media Entrepreneurship at the Cronkite School") to vouch for Professor Doig:

“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.” (emphasis mine)

Yes, if technology could add some accuracy to the news, it would be pretty awesome.  Too bad nobody at your journalism school can tell us whether technology actually can do that -- or how.  (Or if it will work in the blogosphere.)

I can't tell you either, but I can give you an opportunity to figure out your own crowd size numbers.  A simple Google search reveals that Professor Doig's highly scientific satellite-based crowd-size-estimation technology involved reading a press release from GeoEye and following the links to the free satellite image of the inauguration they provided.

In the absence of any other evidence, I'm just going to assume that the professor loaded the picture into Photoshop and counted pixels in different ways until he came up with an answer that he liked.

If you care for a second opinion, Jane's analyzed what sounds like the same image and came up with an estimate of between 1.2 and 1.6 million attendees.  Their press release describes their methodology, and their credentials are, shall we say, somewhat better than NewsBusters' and Professor Doig's.

Incidentally, I also found an enlightening article on MSNBC about the politics of crowd size reports.