Tallying Saturday's "No Kings" protest crowd

By the numbers: Protest organizers say that about 50,000 people went to Waterfront Park on Saturday to protest the Trump administration's policies and that about 80,000 turned out countywide.

• But how did they arrive at those totals?

How it works: Organizers from Take Action San Diego published two papers on how they estimate crowd size. They use a fixed video camera, drone footage, cellphone video and measurements of Waterfront Park.

• A video camera on Harbor Drive showed the number of people who walked by every minute, clocking 1,569 participants a minute for 31 minutes, a method that originates with Harvard's Crowd Counting Consortium.

The other side: Meanwhile, San Diego Police Department Lt. Travis Easter put the turnout at around 25,000, but he noted that the figure was a "best-guess estimate."

• "We were getting different numbers using different estimates, and the numbers were between 35,000 and 15,000, and so 25,000 looked like one of the easiest numbers," he told Axios. "And 25,000 is not dead set. I'm pretty sure it was more than that."

The bottom line: Wendy Gelernter of Take Action San Diego said more people joining protests lets politicians and the media actually see public opinion.

• Faulty crowd estimates without any information on the methods can lead to public distrust, she said, leading to the group to publish its reports.
• June's "No Kings" protest in San Diego drew 69,000 people, according to the group, which used the same crowd measurement methods for that event.