Studying How and Why Maps Go Viral

Geographer Anthony Robinson is studying the phenomenon of viral maps—maps that are widely disseminated on social media, many of which are terrible: superficial, inaccurate or deliberately misleading. One burst of virality occurred in November 2016, when there was an eruption of maps, some silly, others dead serious, showing the outcome of the U.S. presidential election “if only x voted” (where x was women, or people of colour, or some other demographic). This episode is apparently one of the subjects of Robinson’s paper in Cartography and Geographic Information Science, in which he sketches out a framework for evaluating viral maps’ design and the ways they spread. The paper is behind a paywall, but here’s a news article about it from Penn State, where Robinson works.

Previously: When Maps Lie; How to Circulate a Fake Election Map; What If Only … Voted?; Bad Internet Maps: ‘A Social Media Plague’.

‘Empty Land Doesn’t Vote’ and Other Hot Takes

New York Times (screen capture)

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.

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

New York Times (screen capture)

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.

Mapping the 2018 Colombian Presidential Election, First Round

The first round of Colombia’s presidential election was held yesterday. Reddit user jesaub posted this map of the first-round results to r/MapPorn; unlike other maps I’ve seen, it drills down to the municipal level, but as a static map (and fairly low-res at that) it’s not able to show much else. For an interactive map of the results, see El Tiempo’s page, which maps by department but provides municipal-level results via search.

Mapping the Irish Referendum Results

L to R: Referendum Ireland, RTÉ News, The Irish Times.

Even an overwhelming vote margin can be interesting to map, but I’m a bit disappointed with the maps of the Irish referendum held last Friday on whether to repeal Ireland’s constitutional ban on abortion. The official Referendum Ireland website, the Irish Times and RTÉ News all use two-colour constituency map (one colour for yes, another for no); the Irish Times goes a little further and shows choropleth maps for the yes and no sides, but quartiles don’t reveal very much either. The Guardian and even Wikipedia show more granularity. [Maps Mania]

Update: Lots and lots of choropleth maps on the Irish Political Maps Twitter account.

Kenneth Field’s Dot Density Election Map Redux

As promised, Kenneth Field has uploaded the final web version of the quick-and-dirty dasymetric dot density map of the 2016 U.S. presidential election results, which he posted to Twitter last month. Unlike the quick-and-dirty version, the final version is in high resolution and can be zoomed in to quite a preposterous degree. One dot, one vote. [Kenneth Field]

U.S. Supreme Court Rejects Republican Appeal of New Pennsylvania Congressional Map

CNN: “The Supreme Court has denied a request from Pennsylvania Republicans to block new congressional maps that could tilt several key races in Democrats’ favor from being used in the midterm elections.” The new map was imposed by the Pennsylvania Supreme Court after the state’s governor and legislature failed to come up with a replacement for the previous map, which the court had declared unconstitutional; see previous entry.

Meanwhile, last month Wired published a piece that looks at how experts used math and computer simulations to prove to the Pennsylvania Supreme Court that the congressional map exhibited partisan bias. It’s an interesting look at some interesting methodologies.

Kenneth Field’s Dot Density Election Map

Kenneth Field

Earlier this week, Kenneth Field posted a quick-and-dirty dasymetric dot density map of the 2016 U.S. presidential election results to Twitter. It quickly went viral. In a subsequent blog post, he goes into some detail about the process of making the map. “The screengrab was quick and dirty and while there have been many and varied comments on the ‘map’ it’s by no means the finished article. I want to create a hi-res version and also make a web map like the 2012 version. I don’t have time to do this in the next couple of weeks but it will happen. But I am aware of a number of issues and some have already spotted them as have many others.”

See also Field’s gallery of thematic maps of the 2016 U.S. presidential election results.

Pennsylvania Supreme Court Imposes New Congressional Map

New congressional districts for Pennsylvania (Pennsylvania Supreme Court)

A major development yesterday in the case of Pennsylvania’s gerrymandered congressional electoral district map, which was thrown out as unconstitutional last month by the state’s supreme court. The legislature and governor having failed to submit a new electoral district map by the  court’s deadline, the court has imposed what it calls a remedial plan, drawing a new congressional electoral district boundaries for the state of Pennsylvania (court documents). These boundaries will take effect in the primary vote next May, but not next month’s special election.

The general consensus is that the map is more favourable to Democrats than the Democrats’ own proposals: under this map, for example, Clinton would have won the vote in eight seats to Trump’s ten; under the old map, she won the vote in six to Trump’s twelve. Republicans are already planning an appeal. The New York Times does a map-heavy deep dive into the new district boundaries: which areas they include and exclude, and their electoral implications.

Suddenly rendered moot, but still worth pointing to:’s  interactive comparison of congressional map proposals. There were a lot of them, before the court put its foot down yesterday, and this website is a similarly deep dive, analyzing each rigorously.

Freedom in the World, Mapped

Freedom House

The 2018 edition of Freedom House’s annual report on political rights and civil liberties, Freedom in the World, is out, and it’s illustrated by maps that categorize countries into “free,” “partly free” or “not free” and assign them a score out of 100. (I can’t say 1 to 100, because Syria is -1. According to them, it’s been a bad year for global freedom.) The main map, above, shows the three categorizations. It’s a bit reductionist: “partly free” includes Morocco (score: 39) and Bolivia (score: 67), which obscures the fact that Morocco’s score is closer to nearby Algeria’s (35, “not free”) and Bolivia’s is closer to Peru’s (73, “free”) than they are to each other. But scores and categories don’t always map cleanly to one another. A second choropleth map of the scores themselves is more granular, and more revealing:

[Boing Boing]

The Gerrymanderers

When we talk about gerrymandering, about redrawing the political map to favour one’s own party at the expense of another, we talk a lot about the maps themselves. The mapmakers, not so much. Check out this New York Times article on the political consultants who do the redrawing; it focuses on the electoral map of Maryland, which like several other states’ maps is the focus of a court challenge. The process has become even more refined as more and more data becomes available to feed into the redistricting maw.

The Times article points to a similar, earlier article that appeared in the October 2012 issue of The Atlantic and goes into even more depth: “The League of Dangerous Mapmakers.” [Leventhal]

Redrawing Congressional Districts in Pennsylvania

The New York Times

In gerrymandering news, the Pennsylvania Supreme Court threw out the state’s congressional district map earlier this week, ordering the 18 districts—which have been called some of the most gerrymandered in the United States—to be redrawn in time for the 2018 elections. The New York Times explores how the Pennsylvania map could be redrawn in two ways: “One is a neutral map, the kind that might be drawn by a nonpartisan committee. The other is an adventure in extreme gerrymandering that aims to maximize the number of Republican-held seats.” (See above.) Meanwhile, if you live in the state, you might want to take a crack at remapping the districts yourself. Draw the Lines, a project by a nonpartisan watchdog group called the Committee of Seventy, will be holding a contest to redraw the state’s districts later this year.

An Online Atlas of Canadian Election Results is an online atlas of federal and provincial election results in Canada. At the federal level the maps go back as far as the 1925 general election; provincial election maps go back as far as the late 1960s or early 1970s. Poll-by-poll results are available for the most recent elections.

This is a huge resource, all the more impressive given the scope of the data and the fact that it seems to have been done by just one person: J. P. Kirby, a self-described “regular guy interested in politics and elections. I’m also a map geek.” (Naturally.) What I like best is that the atlas shows the historical electoral district boundaries for each election, which is fascinating on its own but must have taken some digging on Kirby’s part. (Also kind of weird to see early 20th-century results overlaid on a modern, OSM-based map with airports and freeways and so on.)

Previously: 1895 Electoral Atlas of Canada.


Peter Kuper, “Trumpworld,” The New Yorker, 12 January 2018.

It’s been a while since we last saw a map of Donald Trump’s world view (previously), but now, inspired by the president’s reported comments about shithole countries, we have a new one from The New Yorker’s Peter Kuper. [Facebook/Twitter]

Previously: The Huffington Post Maps Trump’s World.