Tag Archives: crowd size

Papal visits and large crowds

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Pope Francis visited East Timor earlier this week and many people came out to see him:

Photo by brokenadmiral_ on Pexels.com

opes are popular. So much so that nearly half the population of East Timor gathered Tuesday in a seaside park for Pope Francis’ final Mass in the small Southeast Asian country whose people are deeply Catholic…

East Timor, also known as Timor-Leste, has been overwhelmingly Catholic ever since Portuguese explorers first arrived in the early 1500s and some 97% of the population today is Catholic. They turned out in droves to welcome the first pope to visit them since their independence in 2002, on the same field where St. John Paul II prayed in 1989 during the nation’s fight to separate from Indonesia.

Here is how this crowd compares to other crowds for papal visits:

Other papal Masses have drawn millions of people in more populous countries, such as the Philippines, Brazil and Poland. But the estimated crowd of 600,000 people in East Timor was believed to represent the biggest turnout for a papal event ever in terms of the proportion of the population…

While the East Timor gathering stands out, experts caution against relying on crowd counts that cannot be independently verified. The Vatican communicates crowd estimates that come from local organizers — who have an interest in overestimating the popularity of the head of the Roman Catholic Church.

Crowd counting can be a tricky process. Does it get more difficult if it is a religious crowd as opposed to another kind of crowd?

More broadly, is the experience of a religious large crowd different? It is a unique experience to be crowds of hundreds of thousands of people or more. It does not happen often. The crowd can have a collective experience that is hard for individuals to have on their own. Such a crowd can help produce change or sentiment.

Trying to count the people on the streets in Cairo

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This is a problem that occasionally pops up in American marches or rallies: how exactly should one estimate the number of people in the crowd? This has actually been quite controversial at points as certain organizers of rallies have produced larger figures than official government or media estimates. And with the ongoing protests taking place in Cairo, the same question has arisen: just how many Egyptians have taken to the streets in Cairo? There is a more scientific process to this beyond a journalist simply making a guess:

To fact-check varying claims of Cairo crowd sizes, Clark McPhail, a sociologist at the University of Illinois and a veteran crowd counter, started by figuring out the area of Tahrir Square. McPhail used Google Earth’s satellite imagery, taken before the protest, and came up with a maximum area of 380,000 square feet that could hold protesters. He used a technique of area and density pioneered in the 1960s by Herbert A. Jacobs, a former newspaper reporter who later in his career lectured at the University of California, Berkeley, as chronicled in a Time Magazine article noting that “If the crowd is largely coeducational, he adds, it is conceivable that people might press closer together just for the fun of it.”

Such calculations of capacity say more about the size of potential gathering places than they do about the intensity of the political movements giving rise to the rallies. A government that wants to limit reported crowd sizes could cut off access to its cities’ biggest open areas.

From what I have read in the past on this topic, this is the common approach: calculate how much space is available to protesters or marchers, calculate how much space an individual needs, and then look at photos to see how much of that total space is used. The estimates can then vary quite a bit depending on how much space it is estimated each person wants or needs. These days, the quest to count is aided by better photographs and satellite images:

That is because to ensure an accurate count, some computerized systems require multiple cameras, to get high-resolution images of many parts of the crowd, in case density varies. “I don’t know of real technological solutions for this problem,” said Nuno Vasconcelos, associate professor of electrical and computer engineering at the University of California, San Diego. “You will have to go with the ‘photograph and ruler’ gurus right now. Interestingly, this stuff seems to be mostly of interest to journalists. The funding agencies for example, don’t seem to think that this problem is very important. For example, our project is more or less on stand-by right now, for lack of funding.”

Without any such camera setup, many have turned to some of the companies that collect terrestrial images using satellites, but these companies have collected images mostly before and after the peak of protests this week. “GeoEye and its regional affiliate e-GEOS tasked its GeoEye-1 satellite on Jan. 29, 2011 to collect half-meter resolution imagery showing central Cairo, Egypt,” GeoEye’s senior vice president of marketing, Tony Frazier, said in a written statement. “We provided the imagery to several customers, including Google Earth. GeoEye normally relies on our partners to provide their expert analysis of our imagery, such as counting the number of people in these protests.” This image was taken before the big midweek protests. DigitalGlobe, another satellite-imagery company, also didn’t capture images of the protests, according to a spokeswoman, but did take images later in the week.

Because these images are difficult to come by in Egypt, it is then difficult to make an estimate. As the article notes, this is why you will get vague estimates for crowd sizes in news stories like “thousands” or “tens of thousands.”

Since this is a problem that does come up now and then, can’t someone put together a better method for making crowd estimates? If certain kinds of images could be obtained, it seems like an algorithm could be developed that would scan the image and somehow differentiate between people.