Crowd scientists: Women's March had three times as many people as inauguration

The scientists had better images for the analysis of Mr. Trump’s inauguration crowd, which was concentrated on the mall. But the women’s march was more sprawling and fluid, so the actual number of people at the women’s march could be larger.

It is likely that the timing and location of the march — on a weekend, in a Democratic city in a Democratic region — helped drive the significant turnout.

In addition to wide-angle images, the scientists made use of news images that provided closer views of the crowds, which allowed them to calculate the density of specific areas more precisely.

For the women’s march, they chose a period in time when the crowd was moving the least, from 1:30 p.m. to 2:15 p.m. Using aerial footage and photographs from various angles, the analysts isolated areas with an average density of 2.5 people per square meter, the same method used at Mr. Trump’s inauguration the day before.