After discovering that the National Mall has the bulk of Washington, DC’s geotagged Flickr photos, I wanted to zoom in and study the distribution more closely. In this more-detailed view, the square with the most photos is over the National Air & Space Museum. With over 9 million visitors per year, Air & Space is the city’s most-visited museum. The 14-by-14-pixel in that location has 8,502 photos. However, because that square does not map directly onto the museum, it is only an approximation; you should also examine neighboring squares that might also overlap the museum. And of course we are counting only photos that are geotagged, which is a small subset of all photos actually taken.

The second-most populated square on the grid is over the Verizon Center, with 8,291 photos. The third-highest square falls on the Lincoln Memorial, with 8,171 photos. (Again, these numbers represent only the squares, not the attraction they seem to correspond to.)

It’s interesting to see the trail of photos around the perimeter of the Tidal Basin, with a blank segment on the north by the Kutz Bridge. Perhaps that’s because the sidewalk is too narrow to invite lingering, or because people care only about the trees elsewhere. You can also see a cluster along Pennsylvania Avenue, as well as 7th Street. The entire map has 341,464 photos.

I used the two-tone heat map display, showing squares with less than 5% of the top square’s total getting a gradient from transparent to blue, and for the higher-scoring square using a gradient from blue to cyan. The full map below will show the original map when you move the mouse cursor over the image, to make it easier to see what the heat map is covering.

Next, I zoomed in on Arlington (also using a two-tone heat map split at 5%). The square with the most photos is by the Iwo Jima Memorial (representing 1,620 geo-tagged photos; the neighboring squares are also presumably of the memorial). The second-highest square is in Arlington National Cemetery, by the overlook next to Arlington House (and the Kennedy graves). That square has 1,511 photos. The third-largest square falls not on a tourist attraction, but in the Maywood apartment of a prolific photographer, Kevin Borland. That square has 1,348 photos. The entire map has 36,130 photos.

The next map includes Dupont Circle and Logan Circle, and the stretch of P St between them. Because the number of photos by the Dupont Circle fountain dwarfs all others, I lowered the two-tone heat map split to occur at 2% of the highest square’s value. That top square in Dupont has 1,961 geotagged photos. And the clusters along 17th St and 14th St show how they are challenging each other as centers of activity. The entire map has 22,023 photos.

Lastly, let’s look at Old Town Alexandria. This two-tone heat map splits at 5%. The biggest square (457 photos) is on King St by the Hotel Monaco and Market Square. The entire map reflects 11,079 photos.

I was surprised by how low some of the numbers are; I wonder if the API that I have access to is indeed returning the actual numbers. But in any case, the patterns do seem right.

previous: Washington through the Eyes of Flickr
next: Custom Flickr Maps for Users and Groups

Zooming in on Neighborhood Heat Maps

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