A Redistricting Roundup

The New York Times (screenshot)

Gerrymandering in Texas

The New York Times and Texas Monthly look at the bizarre shapes in the new congressional electoral map of Texas, which gains two new representatives. Texas Monthly’s Dan Solomon: “Across the state, there will be one more majority-Anglo district than under the prior map, and one fewer majority-Hispanic one. The two new seats Texas was awarded for its booming population will be placed in Austin and Houston—and even though non-Anglo newcomers made up 95 percent of the state’s population growth the last decade, both districts will be Anglo-majority.” Kenneth Field has some thoughts. [Maps Mania]

Making Redistricting More Fair

A Surge of Citizen Activism Amps Up the Fight Against Gerrymandering (Bloomberg): “From North Carolina to Michigan to California, voting rights groups, good government advocates, data crunchers and concerned voices are finding new ways into the fight for fair representation, via informational meetings, mapping contests, testimony workshops and new technologies.”

Can Math Make Redistricting More Fair? (CU Boulder Today): “Clelland doesn’t advocate for any political party or for any particular redistricting proposal. Instead, she and her colleagues use mathematical models to build a series of redistricting statistics. These numbers give redistricting officials a baseline that they can compare their own maps to, potentially identifying cases of gerrymandering before they’re inked into law.”

Previously: The Washington Post Examines Proposed Congressional District Maps.

The Washington Post Examines Proposed Congressional District Maps

The Washington Post (screenshot)

Redistricting—and gerrymandering—is one of the blacker cartographic arts. With the release of data from the 2020 U.S. Census, and the changes in state congressional delegations—some states gain a seat or two, some states lose a seat, others are unchanged—new congressional maps are being drawn up for the 2022 elections. The Washington Post takes a look at proposed congressional district maps in Colorado, Indiana and Oregon, and what their impact may be.

Mapping Partisan Sorting in America

Partisanship in Chicago, Dallas-Fort Worth, Los Angeles and New York (New York Times)
The New York Times

The New York Times maps partisan sorting in America—the tendency for voters to self-select into areas where people think and vote the same way they do—down to the neighbourhood level.

The maps above—and throughout this article—show their estimates of partisanship down to the individual voter, colored by the researchers’ best guess based on public data like demographic information, voter registration and whether voters participated in party primaries.

We can’t know how any individual actually voted. But these maps show how Democrats and Republicans can live in very different places, even within the same city, in ways that go beyond the urban-suburban-rural patterns visible in aggregated election results.

It goes beyond racial, urban vs. suburban vs. rural and house vs. apartment splits, to the point where researchers are wondering whether Americans are “paying attention to the politics of their neighbors” when they decide where to live. This has implications not only in terms of electoral targeting (e.g. gerrymandering, voter suppression), but in terms of basic social cohesion.

The maps are based on research by Jacob R. Brown and Ryan D. Enos published earlier this month in Nature Human Behavior.

Previously: Red and Blue vs. Gray and Green.

Field Releases Dot Density Map for the 2020 U.S. Presidential Election

 Dasymetric dot density poster of the 2020 US Presidential election
Kenneth Field. Creative Commons licence.

Kenneth Field has released a dasymetric dot density map of the 2020 U.S. presidential election results. One dot equals one vote. “Data at a county level has been reapportioned to urban areas. Dots are positioned randomly.” It’s in the same vein as his 2016 map, which went all kinds of viral when he posted it in early 2018. A high-resolution downloadable poster is here; an interactive version is here.

Previously: Kenneth Field’s Dot Density Election Map; Kenneth Field’s Dot Density Election Map Redux.

xkcd’s 2020 Election Map

Randall Munroe, “2020 Election Map.” xkcd, 16 Dec 2020.

xkcd did another map thing, so I have to post about it; it’s a rule. This time Randall revisits the design of the map he did for the 2016 U.S. presidential election, in which one figure represents 250,000 votes for each candidate. In a Twitter thread, he explains the rationale for the map:

It tries to address something that I find frustrating about election maps: Very few of them do a good job of showing where voters are. […] There are more Trump voters in California than Texas, more Biden voters in Texas than New York, more Trump voters in New York than Ohio, more Biden voters in Ohio than Massachusetts, more Trump voters in Massachusetts than Mississippi, and more Biden voters in Mississippi than Vermont.

Previously: xkcd’s 2016 Election Map.

Mapbox’s Election Map Contest

Mapbox is holding an election mapping challenge. Entrants are asked to create, using the Mapbox basemap and compatible tools and platforms, “an original, publicly viewable interactive map, map-based data visualization, or application that uses location tools and focuses on an elections-related theme.” Entries are due November 8, and must be accompanied by a public blog post explaining the project.

Previously: Mapbox Elections.

Field’s Virtual Talk on Election Mapping

Kenneth Field’s virtual talk on the cartography of elections, given to University of South Carolina students on 25 September 2020, is now available on YouTube. “It explores the way in which map types and their design mediate the message, and using examples from elections shows different versions of the truth.” Also includes material from Ken’s forthcoming book.

Red and Blue vs. Gray and Green

New York Times

The New York Times uses the colours in aerial images as a proxy for political leanings: rather than red-and-blue electoral maps, the political landscape, Tim Wallace and Krishna Karra argue, is more green and gray.

The pattern we observe here is consistent with the urban-rural divide we’re accustomed to seeing on traditional maps of election results. What spans the divide—the suburbs represented by transition colors—can be crucial to winning elections. […] At each extreme of the political spectrum, the most Democratic areas tend to be heavily developed, while the most Republican areas are a more varied mix: not only suburbs, but farms and forests, as well as lands dominated by rock, sand or clay.

This is a generalization, to be sure, but so are most political maps, and the notion that urban areas tend to vote Democratic while rural areas tend to vote Republican isn’t what I’d call a revelation. Still.

Canadian Election Atlas Adds 2019 Results

Election-atlas.ca, the collection of historical Canadian election results maps I first told you about in 2018, has added poll-by-poll results for the 2019 Canadian federal election. Also, since we last saw them it seems they’ve extended their historical results further back in time—as far back as 1896 for the federal results.

Previously: An Online Atlas of Canadian Election Results; A Cartogram of Canada’s Election Results; More Canadian Election Maps; Mapping the Canadian Election Results: Technical Details.

Mapbox Elections

Mapbox

This week Mapbox launched a tool for the upcoming 2020 U.S. elections: Mapbox Elections, “a resource to help individuals, journalists, and organizations cover the elections, analyze the results, and build modern maps to display it all.” Their first product is a dataset including U.S. presidential election results from 2004 to 2016.

Mapping Canadians’ Attitude Towards Climate Change

Screenshot of interactive map of Canadian public opinion on climate change
Screenshot

Researchers have released an interactive map showing Canadians’ opinions about climate change—whether it’s happening, and what we should do about it—and, more significantly, the regional variations in that opinion, down to the riding level. Not surprisingly, the oil- and coal-producing regions are much more likely to be climate skeptics.

The map is based on surveys of more than 9,000 Canadians taken between 2011 and 2018, which raised my eyebrows a bit: public opinion can change a lot over seven or eight years, after all. But the researchers did so to get a more accurate sense of regional opinion: opinion polls are usually based on a small national sample; regional breakdowns of that sample have large margins of error, and getting accurate regional samples would be a lot more expensive. More at Global News.

Mapping the Canadian Election Results: Technical Details

Bothered by the widespread use of Web Mercator by Canadian news outlets to show last week’s election results, Kenneth Field has posted an article that aims to address the problem. Static maps of Canada tend to use a conic projection like the Albers or the Lambert, and that’s the case for print election maps as well. Online interactive maps, on the other hand, use off-the-shelf tools that use Web Mercator, which results in the sparsely populated territories looking even more enormous. But that doesn’t have to be the case, says Ken, who shows us, with a few examples, how use ArcGIS Pro to create interactive maps using a conical projection.

Meanwhile, Mark Gargul writes in response to Ken’s critique of his cartogram of the election results. Mark describes himself as an amateur and readily admits that other cartograms are “clearly more aesthetically pleasing. On the other hand, I was going for something different with my cartogram—specifically, to try to preserve riding-adjacency as much as possible.”

The other thing Mark was going for in his cartogram was to indicate the urban-rural split: metropolitan areas are given a black border: it’s easy to see which ridings are in Montreal or Toronto; seats that are partially urban and partially rural straddle those borders.

So it’s doing several things at once that may not be immediately apparent.

Previously: A Cartogram of Canada’s Election Results; More Canadian Election Maps.

More Canadian Election Maps

I hit “Publish” too soon last night. Kenneth Field and Craig Williams put together a series of maps showing the Canadian election results in a number of different ways: we have a value-by-alpha map, a proportional symbol map, and two kinds of dot density maps: one showing the winners, one showing all votes per constituency. (One dot equals 100 votes; the dots are spread evenly across constituencies, even when people aren’t. You can’t have everything.) And it’s on the Lambert, not the Mercator.

Speaking of the Mercator. Maps Mania’s roundup of Canadian election results maps notes that the Canadian media’s interactive maps (e.g. CBC, Global, Globe and Mail) invariably resorted to Web Mercator, largely because of the mapping platform used. (In-house infographics team? Don’t be ridiculous.) Web Mercator is singularly bad for Canadian election maps, because Nunavut: it’s the largest electoral district by area (1.9 million km2) and the smallest by population (31,906). It’s enough of a distortion on the Lambert: Mercator makes it worse.

As for cartograms, Ken hated the one I posted last night; Keir points to Luke Andrews’s Electoral Cartogram of Canada, which is a bit nicer, and uses only one hexagon per riding instead of seven. Keir also points to this animation that shifts between a geographical map and a cartogram. It’s hard to recognize Canada in cartograms, because it’s difficult for us to grasp just how many people live in southern Ontario.

Previously: A Cartogram of Canada’s Election Results.

A Cartogram of Canada’s Election Results

This cartogram shows the seat-by-seat results of the federal election held last Monday in Canada. It was uploaded to Wikipedia by user Mark Gargul to illustrate the 2019 Canadian federal election article, and it’s a welcome departure from the usual election results maps in this country.

(An example of the usual results map is Elections Canada’s official map of the unofficial results, in PDF format.)

Canadian election results maps generally use geographic maps, usually the Lambert conformal conic projection that most maps of Canada use (though sometimes it’s the Mercator!) rather than cartograms. Which means that Canadian maps suffer from the same “empty land doesn’t vote” problem that U.S. maps have, though it’s mitigated by the fact that vast rural and northern seats are often won by different parties: you don’t have the same sea of one colour that you get in the States.

That said, Canada is overwhelmingly urban, and so are its electoral districts. Most election results maps resort to using multiple inset maps to show the urban results. (Elections Canada’s map has 29 of them.) Gargul’s cartogram sidesteps both problems neatly; on the other hand, it’s next to impossible to find your own damn constituency (it’s hidden in the mouseover text). If the disadvantage of empty-land election results maps is that the colours aren’t representative, their advantage is that you can tell what regions voted for whom, at least if you know your geography.