Tuesday 1 November 2016

The NYT election map

It's election time in the US. It has been for well over a year (which is madness in itself) but we're down to the wire now with only a week to go before polling in what must be one of the most hate-fueled, vitriolic contests ever. Lies and misinformation have taken centre-stage but the sad truth is there are people (people who vote) who are easily taken in by lies and misinformation. They are sold it as a version of the 'truth' they can relate to and in which they wholeheartedly believe. And so that's how propaganda becomes reality and how candidates gain disciples. It's often the same with maps because they too sell a version of the truth.

We're arguably on the cusp of something far more important than worrying about a map in a newspaper but to my mind, at least, today's HUGE map in the New York Times warrants some cartonerd attention.

It is a truly magnificent piece of work. Large format. Eye-catching. Detailed. The US is a big country so if you want to show 30,000+ zip codes you better make your map big. I am a huge admirer of the New York Times graphics team and their cartographic work but this map, I'm afraid, contributes to the misinformation that has become so toxic this election season. Let's not worry about the periphery because it's the main map that takes centre-stage. It's that image which is defining and the impression that people see.

So what do they see? RED...lots of red. Any map that attempts to summarise a sparsely populated data set into a surface that exhausts space will mislead. It's inevitable. And with the USA, with a very heterogenous population distribution and vast swathes of land with barely a single rattlesnake of voting age it's a problem that is accentuated. The map uses Zip Code Tabulation Areas instead of counties, voting precincts or other geographies. There are problems with how ZCTAs mis-shapes the view but, frankly, any arbitrary boundaries have the same problems - the Modifiable Areal Unit Problem - statistical (and ultimately visual) bias that results with how you aggregate data into areas. The geography is what it is...but rather than perpetuate visually incongruous issues it's beholden on map-makers to deal with it.

For the last few years in my day job I've given a workshop at the Esri International User Conference that takes a single dataset of the 2012 election results and explores a range of about 20 different ways to present the very same data - each of which tells a very different story. Some of the maps can clearly be used to portray a particular dimension of the result and some can be used in deplorable ways (pun intended). Some reveal detail. Some mask it. Some show red. Some blue. You can see the full range of maps here if you're interested. The point of the session is to open people's eyes to the inherent biases that maps contain. What surprises me year on year is that an audience of people heavily invested in geo are equally surprised at the problems we explore. I guess it's to be expected - not every geo-expert is going to be a cartographic expert and they come to the session to learn and that's a great thing. But they are merely a small fraction of the population. The vast majority have no access to this sort of education. More than that - they have no idea they might even benefit from it or that there's a problem with how they read the maps they are served.

It's really a much bigger problem of geographical illiteracy and the lack of the basic need to view maps and graphics critically. With all these much larger issues it therefore becomes crucial for media organisations and those involved in communicating information to be cognisant of the limitations of the consumer. It's not really their fault - we're all born that way and we have a natural tendency to believe what we see, especially if it comes from a so-called reputable, impartial source. Maps should portray reality in a way that deals with the biases people inevitably see - to counter them rather than feed them. You only have to read the comments in reply to the NYT tweet to see how the map has been viewed and interpreted.

The problem with this New York Times map is the country itself which, admittedly, there isn't much they can do about but they could deal with the problem using different maps.  The size of the areas used to summarise the data are unequal. Some are therefore more visually prominent than others. Republicans hold on to large swathes of centrally located territory. Democrats get a shed-load of votes from the smaller, peripheral northeast. Additionally, they contain very different numbers of people so population density is unequal across the map - yet in terms of the symbology, each area is treated the same.

So you end up with large swathes of sparsely populated large areas in the mid-west being seen prominently and very small, densely populated areas on the coasts being seen much less prominently. The problem is compounded by two other factors - colour and focus. Red for republican is a colour that is seen more brightly than blue for Democrat. It is cognitively processed as 'more important'. Our eyes also naturally tend towards the centre of an image and a map on first inspection - so that's our initial focus. this all adds up to one massively misleading picture of the political geography of the USA. It screams REPUBLICAN which given Trump's persistent comments about the corrupt media is either an attempt for NYT to redress the balance or the Russians are to blame. And yellow for the marginal areas? I understand the desire for a neutral colour but in a generally two-horse race (mule, elephant, whatever) adding in other colours paints a different picture as well.

It can be different as these following maps of the 2012 election results, mapped by county, show. Using a value-by-alpha approach that overlays a layer of population density that is symbolised so that sparsely populated areas are more opaque will modify the image. It tunes out sparsely populated areas and brings a little focus to the areas with more people (more voters). All that deep red on the NYT version has now gone. Focus is shifted.

A cartogram does a similar job but by changing the shape of the areas - either warping them in relation to population density (e.g. a population equalising cartogram) or by giving each unit area the same shape (e.g. a hexagon grid). Yes, these are abstract and there's sometimes a challenge understanding the geography but they deal with the problems.

There's even the simple, yet effective, proportional symbol map that often gets overlooked. Symbol overlaps are often hard to reconcile but the symbol sizes do a good job of showing where there is more and where there is less as well as encoding the different colours.

Finally in this small selection of the myriad of alternatives, a dasymetric technique which uses a secondary layer of data into which you can reapportion the data can also show a more accurate distribution of information (e.g. dasymetric dot density) though, of course, any map of population data presented in this way will take on a similar appearance because, well, that's where people live!

Ultimately, there are dozens of different ways that the map can be made. None are 'right' and none are 'wrong' but they all tell different versions of the truth. This isn't cartographic pedantry. It's an important issue because it plays to people's views, opinions and search for the truth. My point here, is that maps can be extremely dangerous graphic tools. The NYT have, in my opinion, contributed to the misinformation that has enveloped this election by publishing this map in the form they chose. It presents a version of the truth that suits a particular view of reality. It is biased and dangerous. It's also too late because it's out there now and is simply just another piece of rhetoric people can use to support their own version of the facts.

By the way, I don't get to vote in the US election but I have lived and worked in the US for 5 years and call it home. Please...do yourselves a favour and go vote. You only have to look at what happened in the UK a few months ago where the vote was to leave Europe...a vote massively impacted because many people failed to turn out to vote who would otherwise have voted not to leave. You can't vote by liking or re-tweeting. Whatever the map says to you...just go and vote and help redraw the one you want.

UPDATE: Since writing this less than an hour ago the Washington Post has published a very well-timed piece entitled Election maps are telling you big lies about small things. They've been advocating cartograms based on one area per electoral college vote which I like. It retains a State-based appearance (which isn't as difficult to read as the population equalising versions) while doing a good job of presenting a visually balanced view of the data. I encourage you to read.

UPDATE 2: And now a good review of past approaches from NYT here. A rebuttal of the criticism they've faced? Maybe. They try and frame the big map as an attempt to look at the way physical geography impacts political patterns. That's a very nuanced way to explore the distribution of voting and I'd still argue that most who read the map will take away one message...more red = more Republican. Seven days out from the election is not the time to be playing with people's inherent perceptual and cognitive bias.


  1. The proportional symbol map seems like the best way to convey both the location of voters and their preferences. The one here could be improved by gradient shading, rather than red/blue only.
    As someone born in the midwest, I have to point out that those large, less populated counties are mostly in the west.

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  3. Nice summary of the different cartographic techniques. I'm also a big fan of the NYT's work.
    Although, as a true outsider, can I point out that the US electoral vote system does not tally in the slightest with population.
    E.g. https://d3n8a8pro7vhmx.cloudfront.net/fairvote/pages/199/attachments/original/1450119297/2008votersperelector.pdf