The Map Room

The hot takes about the New York Times’s detailed map of the 2016 U.S. presidential election results (see previous entry) have been coming in fast. Most of the critiques focus on the map’s failure to address population density: a sparsely populated but huge precinct appears to have more significance than a tiny district crowded by people. See, for example, Andrew Middleton’s post on Medium, Keir Clarke’s post on Maps Mania or this post on Wonkette—or, for that matter, a good chunk of cartographic Twitter for the past few days. (It’s not just Ken, is what I’m saying.)

The responses to those critiques generally do two things. They point out that the map had a specific purpose—as the Times’s Josh Katz says, “we wanted to use the 2016 results to make a tool that depicted the contours of American political geography in fine detail, letting people explore the places they care about block by block.” As he argues in the full Twitter thread, showing population density was not the point: other maps already do that. Others explore the “empty land doesn’t vote” argument: Tom MacWright thinks that’s “mostly a bogus armchair critique.” Bill Morris critiques the “acres don’t vote” thesis in more detail.

Relatedly, Wired had a piece last Thursday on the different ways to map the U.S. election results, in which Ken Field’s gallery of maps plays a leading role.

Previously: The New York Times’s Very Detailed Map of the 2016 U.S. Presidential Election.

It’s 2018. The 2016 U.S. presidential election is nearly two years in the past. But that didn’t stop the New York Times from unleashing a new map of the 2016 election results earlier this week. On the surface it’s a basic choropleth map: nothing new on that front. But this map drills down a bit further: showing the results by precinct, not just by county. The accompanying article sets out what the Times is trying to accomplish: “On the neighborhood level, many of us really do live in an electoral bubble, this map shows: More than one in five voters lived in a precinct where 80 percent of the two-party vote went to Mr. Trump or Mrs. Clinton. But the map also reveals surprising diversity.”

Kenneth Field has some objections to the map. “So you have smaller geographical areas. Detailed, yes. Accurate, certainly. Useful? Absolutely not because of the way the map was made.” It’s a choropleth map that doesn’t account for population: “An area that has 100 voters and 90 of them voted Republican is shown as dark red and a 90% share. Exactly the same symbol would be used for an area that has 100,000 voters, 90,000 of whom voted Republican.” It gets worse when that thinly populated precinct is geographically larger. (Not only that: the map uses Web Mercator—it is built with Mapbox—so Alaska is severely exaggerated at small scales.) There are, Ken says, other maps that account for population density (not least of which his own dot density map).

The Times map has a very specific purpose, and Ken is going after it for reasons that aren’t really relevant to that purpose. The map is aimed at people looking at their own and surrounding neighbourhoods: the differences in area and population between a precinct in Wyoming and a precinct in Manhattan wouldn’t normally come up. It works at large scales, whereas Ken’s point is more about small scales: zoom out and the map becomes misleading, or at the very least just as problematic as (or no more special than) any other, less granular choropleth map that doesn’t account for population. The map isn’t meant to be small-scale, doesn’t work at small scales, but then people regularly use maps for reasons not intended by the mapmaker. The mistake, I suspect, is making a map that does not work at every scale available at every scale.

Update: See this post for more reactions to the map.