Thursday, August 29, 2013

Crowd estimate of Anti-Pork Barrel Rally at Luneta last 26 Aug 2013

A friend in Filipinos for Life asked me to make make a crowd estimate of the Luneta Rally last 26 Aug 2013.  She sent me an aerial photograph of the crowd by Architect Paulo Alcazaren in Inquirer, which I used it as the basis of my crowd estimate, assuming there are no other persons outside the picture.  There is also another excellent photo by Alcazaren in GMA Network.

The first thing I did was to check the Google Earth.  I want to make sure of the extent of the boundaries of the crowd in Alcazaren's picture.  I found that the extent of the crowd in the picture is bounded by the road along Quirino's Grandstand in the West, Roxas Boulevard in the East, South Drive in the South, and Katigbak Parkway in the North.  The boundaries are drawn with a red line.  There are clusters of crowds and some areas have no crowds.  So what I did is to estimate an area in front of the Quirino's Grandstand (bounded by yellow line) where the crowd can fit more compactly, as seen from the perspective estimates of crowd clusters in the Inquirer's photograph.  It turns out that the this smaller area where all the crowd can fit is 225 m x 225 m, assuming that the scale in Google Maps is correct, which is about 2 cm: 50 m in my computer screen.  The total area of the yellow bounded square is 50,625 sq.m. or just 50,000 sq.m. for simplicity.  A loose crowd would have about 1 person /sq. m.  A dense crowd is about 4 persons /sq. m.  My estimate is 2-4 persons per square meter, which gives a crowd of 100,000 to 200,000 persons.

Photo of Luneta crowd during 26 Aug 2013 with boundary lines yellow and red. Photo by Almacazaren
Red line is the boundary of the crowd at the Luneta rally of 26 August 2013.  Yellow line is the boundary of the crowd if they were closely packed.  Photo courtesy of Paulo Alcazaren. 
Photo of Luneta crowd during 26 Aug 2013 with boundary lines yellow and red. Photo by Google Earth.
Red line is the boundary of the crowd at the Luneta Rally of 26 August 2013. Yellow line is the boundary of the crowd if they were closely packed. Photo courtesy of Google Earth.
Photo of Luneta crowd during 26 Aug 2013 with boundary lines yellow and red. Photo by Google Maps.
Red line is the boundary of the crowd at the Luneta Rally of 26 August 2013. Yellow line is the boundary of the crowd if they were closely packed.  Photo courtesy of Google Maps. Area of the closely packed crowd is 50,000 sq m.  Crowd estimate is 100,000 to 200,000 persons.



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