A Primer on Election Map Cartography

With less than two weeks before the 2016 U.S. presidential election, it’s time for a refresher on election map cartography, particularly in the context of U.S. presidential elections.


2012 U.S. presidential results. At right, a cartogram scaled by electoral vote. Maps by Mark Newman.
2012 U.S. presidential results. At right, a cartogram scaled by electoral vote. Maps by Mark Newman.

Let’s start with the basics: at All Over the Map, Greg Miller explains the problem with U.S. presidential election maps—big states with few electoral votes look more important than smaller states with more votes—and introduces the idea of the cartogram: a map distorted to account for some variable other than land area.

Here are some cartograms of the 2012 U.S. presidential results (see above). Previously: Cartograms for the 2008 U.S. Presidential Election Results.

The Map That Started It All

Scribner's statistical atlas of the United States,
Plate 11: Popular Vote: 1880. From Fletcher W. Hewes and Henry Gannett, Scribner’s Statistical Atlas of the United States, 1883. Library of Congress.

Back in 2014, Susan Schulten looked at the map that may have started it all: an 1883 choropleth map of the 1880 U.S. presidential results (see above) that shows results not only on a county-by-county basis, but also the amount the winning candidate won by.

The map may not look advanced today, but in 1883 it broke new ground by enabling Americans to visualize the spatial dynamics of political power. Readers responded enthusiastically. One reviewer pointed to the Republican counties in Arkansas—something left invisible on a map of the Electoral College returns—and wondered what other oddities of geography and history might be uncovered when election returns were more systematically measured. In other words, the map revealed spatial patterns and relationships that might otherwise remain hidden, or only known anecdotally. Perhaps its no coincidence that at the same time the two parties began to launch more coordinated, disciplined, nationwide campaigns, creating a system of two-party rule that we have lived with ever since.

(This map also inverts the modern colours for the two main U.S. political parties: here the Democrats are red and the Republicans are blue. Those colours were standardized only fairly recently.) [Geolounge]

Rethinking Election Map Design

Back to Greg Miller, who has a roundup of different kinds of election maps throughout history, including the maps we’ve seen here so far, Andy Woodruff’s value-by-alpha maps (previously) and others.

For other ways of mapping election results, see this gallery of thematic maps, which includes things like 3D choropleth maps, dot density maps, and all kinds of variations on cartograms and choropleth maps. There’s more than one way to map an election. [Andy Woodruff]

Texas Monthly on Smith Map Studio

Smith Map Studio
Smith Map Studio

Texas Monthly has a piece about Christopher Alan Smith, who for the past decade has been creating original maps, mostly of Texas and Texas-related subjects. It’s been his full-time gig since 2008. Smith uses a mixture of pen-and-ink and acrylic paints:

I tend to follow the style of postage stamps and currency. I use a pen-and-ink stipple technique, which is a series of dots that create the illusion of halftones. Cross-hatching is another method, using lines instead of dots. I’ve also started using engraved wood to give the maps a layered, 3-D look. For example, on my Thirteen Colonies map, I illustrated the coastline on two layers of hardboard.


Mapping Clinton and Trump’s Upside Potential (Whatever That Means)


Earlier this month FiveThirtyEight built a county-by-county model showing where both Hillary Clinton and Donald Trump’s “upside potential” — by which they meant where they would each benefit from the shifts in the electoral landscape. Compared to 2012, Clinton is underperforming with non-college-educated whites and Trump is underperforming with Asians, African-Americans, Latinos and college educated whites.

To get a handle on how these shifts could affect the electoral landscape, we modeled how many of Romney’s votes came from college-educated whites and minorities and how many of Obama’s votes came from non-college-educated whites in each state, county and congressional district. The difference between these two vote totals, shown in the map above, can tell us where Clinton and Trump have the most potential to build on 2012.

The authors went on to game out what that might look like in terms of the electoral vote if one in five voters in those shifting groups switched allegiances.

Mapping Scottish and/or Nonexistent Islands

scotland-mapping-islandsThe Scotsman’s review of Scotland: Mapping the Islands  focuses on the Scottish islands that didn’t exist, particularly in a 1560 map by Italian mapmaker Giorgio Sideri (aka Callapoda). On the other hand: “In contrast to Callapoda’s chart, many genuine Scottish islands were omitted from maps of Scotland altogether until only 150 years ago.” [Tony Campbell]

undiscovered-islandsSpeaking of islands that didn’t exist, and maps thereof, there’s a new book about them. The Un-Discovered Islands by Malachy Tallack (Birlinn, October). “Gathered in the book are two dozen islands once believed to be real but no longer on the map. These are the products of imagination, deception and simple human error. They are phantoms and fakes: an archipelago of ex-isles and forgotten lands.” Available in the U.K. for now (or via third-party sellers); the Shetland News story about the book suggests that a U.S. edition is forthcoming. Official website. [WMS]

Previously: New Map Books for October 2016.

River Basins in Rainbow Colours


The latest map to go viral is Robert Szucs’s dramatic and colourful map of the U.S. river basins. It’s even more spectacular in high resolution. Made with QGIS, the map separates river basin by colour and assigns stream thickness by Strahler number. I do have a couple of quibbles. The map doesn’t distinguish between the Hudson Bay and Atlantic watersheds: the Great Lakes and Red River basins are coloured the same way. And speaking of the Great Lakes, I have no idea why they look like ferns here. The map is available for sale on Etsy, along with similar maps of other countries, continents and regions. Daily Mail coverage.

Exhibition Writeups

A couple of reviews of recent map exhibitions that I’ve mentioned before. First, the Arctic Journal looks at the Osher Map Library’s current exhibition, The Northwest Passage: Navigating Old Beliefs and New Realities (see previous entry). And the St. Louis Library’s fantasy maps exhibit (see previous entry), which wrapped up earlier this month, got a writeup from Book Riot. [Book Riot/Osher Maps]

Road Trees

The Road Trees project has produced animated isochrone maps showing road networks erupting fractally from a single departure point.

An isochrone in a map shows with the same color all points from which it takes the same time to arrive to a specific location.

We chose 10 locations around the world and for each of them constructed the isochrones on top of the road network of the corresponding country. Consequently, we plot these isochrones using a dynamic color palette representing the diffusion from the location of interest to any other point of the road network.

Unexpectedly, we found that the isochrones follow beautiful fractal patterns, very similar to networks shaped in the Nature by rivers, veins, or lightnings.

[Stephen Smith]

Fewer Maps, But Better Maps

Alan Smith of the Financial Times adds to the conversation about when to use a map to present your data, when not to—he gives an example where a gridded infographic is a much better choice than a map—and when more than one map is required to tell the whole story. “So as lovers of maps, we are keen to create beautiful ones whenever they offer a crucial addition. Truly appreciating them, however, means not defaulting to a map just because you can. Like a lot of things in the world of data visualisation, the right way to use them is to follow the mantra ‘fewer, but better’.” [WMS]

Previously: The End of Maps in Seven ChartsDon’t Make a Map.

The Map That Came to Life


As part of National Map Reading Week, the British Library’s map blog points to at least one example of how map reading used to be taught.

One of the most celebrated 20th century children’s map reading guides is showcased in our forthcoming exhibition Maps and the 20th Century: Drawing the Line. Published in 1948, Ronald Lampitt and James Deverson’s The Map that Came to Life follows the story of John and Joanna who use an Ordnance Survey map to walk to town. As they pass over fields, past houses and along footpaths, their surroundings are compared with map adjacent on the same page. The fields turn into contoured blank spaces, houses become black cubes, footpaths dashed lines. Map literacy is acquired by the reader as they accompany the children on their virtual journey, matching map with reality.

In The Map that Came to Life the map is portrayed as an objective, precise and above all truthful mirror of nature. And this inherent trustworthiness enabled maps to become important features of the lives of successive generations of people.

The idea that maps are objective and truthful is not something that would fly today, I think, but in the context of entry-level map education, which in Britain always seems to be specifically in terms of how to read an Ordnance Survey map, rather than maps in general, it seems harmless enough.

A complete scan of the book is available on this website. Back in 2008, Philip Wilkinson talked about the book on the English Buildings blog.

A Historical Atlas of Tibet

historical-atlas-tibetKarl E. Ryavec’s Historical Atlas of Tibet (University of Chicago Press, May 2015) was reviewed in India Today by an unusual personage: Nirupama Rao, who among other things has served as India’s ambassador to China and the U.S. Rao calls it “a much-needed and welcome work of scholarship that should benefit and enlighten committed scholars and Tibet aficionados alike. This is a 200-page atlas that is a revelation in itself.” [Tony Campbell]

Gregor Turk’s Conflux

Gregor Turk, Choke: Hormuz- Land (left) & Water (right). | wood and rubber | 20" x 20" x 3"
Gregor Turk, Choke: Hormuz — Land (left) and Water (right). Wood and rubber, 20″×20″× 3″.

Gregor Turk’s Conflux is on display at Spalding Nix Fine Art in Atlanta, Georgia until October 28. Conflux “features wall-mounted box-like maps of global choke points, strategic locations where passage by land or sea is constricted.  Coastlines are depicted as alternating positive and negative cut-outs, framed in a grid and wrapped with repurposed rubber (bicycle inner tubes). Shadows and negative space come into play with the stark structures.” Turk’s past art includes ceramics and public art installations inspired by topographic and city maps; see also his 49th Parallel Project. [The Map as Art]