The crowd at President Barack Obama’s inauguration topped 2 million — at least that figure was being reported Tuesday morning — but it seems to have been steadily shrinking.

As a rule, the St. Louis Post-Dispatch is reluctant to give crowd estimates, unless the turnout is a meaningful part of the story.  The official Post-Dispatch policy is pretty simple: “Estimates always must be attributed to someone. If there is a dispute, both claims should be given.” That’s it. No definition of who “someone” is or what qualifies “someone” to estimate a crowd.

The Post-Dispatch’s lead story today put the crowd at “more than 1 million,” without attributing that figure.   That breach of policy seemed permissible, since the “more than 1 million” phrase was being used widely and pretty much by all media.

In the commemorative Extra Edition the Post-Dispatch published Tuesday afternoon,  the lead story stated: “A momentous crowd, estimated to be as high as 2 million people…..” Again, no source was given for the estimate. By evening, as this morning’s editions were being edited, we chose to use the more conservative “more than 1 million.”

Today, though, even that number is being challenged by some.

A Los Angeles Times article traces the moving  target:

“More than 1 million spectators convened on the National Mall to watch Barack Obama take the oath of office Tuesday, but it was unclear if the crowd surpassed the record thought to have been set at Lyndon B. Johnson’s 1965 inauguration.

“Though early estimates ranged as high as 2 million people, satellite images of Obama’s swearing-in suggested the crowd was probably about half that, said Clark McPhail, who has been analyzing crowds on the National Mall since the 1960s. ‘It was sparser than I thought,’ said McPhail, a professor emeritus of sociology at the University of Illinois. ‘There were lots of open spaces.’”

Later, that Los Angeles Times article reports:

“On Tuesday morning, the Washington Post initially cited security sources who put the crowd at 1.8 million.

“The Associated Press, which did its own analysis, estimated “more than 1 million.”

“The National Park Service has not done official estimates in more than a decade, complying with a congressional order to stop after a controversy over how many people attended the Million Man March in 1995. Estimates then varied from 400,000 to more than 1 million.

“Park service spokesman David Barna said the agency probably would produce a number this year because of the historic nature of the event and public demand for an estimate.

“‘We don’t think anyone in Congress will be really upset,’ he said.”

An item linked from the Romenesko media newsletter quotes an Arizona State University professor as saying the crowd didn’t even reach a million:

“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.’”