Land use twitter has been on a population density kick recently. These exchanges motivated me to put together an interactive graph of population density distributions, something I’ve been meaning to do for a while. (Many thanks to @woolie and this blog post, whose work I’ve borrowed heavily from!)
So here it is. There are two drop downs: one for selecting cities to plot, and another for choosing the y axis scale (raw population or percent). It spits out something like this:
We interpret any position on the line as “y people live in census tracts that are as least as dense as x.” For instance, in the graph above, we could look at DC and note that there are about 800,000+ residents living at densities of at least 10,000 people/square mile, whereas that number is only about 250,000 for Houston residents.
A note about geography here: cities are defined as Census-designated urban areas. This is the most appropriate level of analysis, since MSAs cover too much rural land and cities have arbitrary political boundaries. (The 30 largest urban areas by population are available in this tool.) The smaller unit is census tracts, which I think is small enough to capture the fine-grained distribution of population density and large enough to avoid massive outliers resulting from tiny land area. All data are from 2010.
I put this together somewhat hastily and might do more in the future to improve functionality if people are interested (i.e. add tooltip interactivity). Let me know what you think!