I [Nelson] am using simple tract-level population/gender counts from the US Census Bureau. Because their tract boundaries extend into the water and vacant area, I used NYC’s Bytes of the Big Apple zoning shapes to clip the census tracts to residentially zoned areas -giving me a more realistic (and more recognizable) definition of populated areas. The census breaks out their population counts by gender for five-year age spans ranging from teeny tiny infants through esteemed 85+ year-olds.
And here’s Gonzalez:
Between ages 0 and 14, the entire map is more or less an evenly mixed purple landscape; newborns, children and adolescents, after all, can’t really choose where they live – let alone where they’re born. But between the ages of 15 and 19, something interesting happens. As Nelson writes on his blog:
We are in the age-span where teens/young adults can choose where to live. And they choose paths that are not gender-neutral. Immediately we see clusters of females and, to a lesser extent, clusters of males. What’s the deal? College. And prisons.
Morningside Heights positively glows pink as the home of Barnard College, as do other institutions of learning sprinkled throughout Manhattan. The garment district is another draw.
We also start to see the filling of Rikers Island with green dots as young men begin to populate the jail complex. . . .
The analysis for other age groups continues in greater detail over at Nelson’s blog. In their early twenties, for example, professional women tend to gather in Midtown Manhattan, while swaths of early-twenty-something masculinity emerge in places like the SUNY Maritime College, and Yeshiva University. . . . The forties and fifties are characterized by a re-segregation of genders, and a thinning population. . . .
At 85 and older, New York is essentially pink. Women outnumber the remaining men at a rate of better than two to one. Various retirement communities popular with women become apparent, almost as strongly as their geographic preferences in their teens and twenties. Those two eras mark their times without men, when whole neighborhoods are almost empty of males their peer. The boys have moved on.
Who knew a map could be so poignant?
These maps are a beautiful illustration of the Chris Rock effect. Chris Rock says things we all know are true. But he says it so well that we get a shock of recognition, the joy of relearning what we already know, but hearing it in a new way that makes us think more deeply about all sorts of related topics.
In the past, I’ve used the Chris Rock concept to understand the different attitudes in statistical graphics and information visualization. Statisticians, following John Tukey and Bill Cleveland, emphasize the ability of graphical data displays to reveal things that we have never thought of before. In contrast, graphics designers celebrate innovative designs and visual juxtapositions that reveal interesting aspects of data but without highlighting any particular comparisons.
I’m happy to discuss the Chris Rock effect in the context of Nelson’s maps, because this should make it clear that the Chris Rock phenomenon is not a bad thing. It’s not a put-down of a graph to say that it reveals things we already know (and, for that matter, I’m a big fan of Chris Rock). Re-saying what we already know, quantifying it, and expressing it in other ways, is an important part of how we get to understand the world.
P.S. Nelson also writes:
I, along with most other cartographers these days, am really into dot density mapping. It is way more truthful a means of presenting relative geographic dispersion and affiliation than, say, choropleth mapping, which will be the carto-whipping-post of 2013.
I’m not all that into carto-whipping myself, but I agree with Nelson that dotmaps are cool, and I’m glad that technology has caught up with this excellent idea.