Axis Lines in Charts

The British election campaign is wrapping up as it heads towards the general election on Thursday. I haven’t covered it much here, but this piece from the BBC has been at the back of my mind. And not so much for the content, but strictly the design.

In terms of content, the article stems from a question asked in a debate about income levels and where they fall relative to the rest of the population. A man rejected a Labour party proposal for an increase in taxes on those earning more than £80,000 per annum, saying that as someone who earned more than that amount he was “not even in the top 5%, not even the top 50”.

The BBC looked at the data and found that actually the man was certainly within the top 50% and likely in the top 5%, as they earn more than £75,300 per annum. Here in the States, many Americans cannot place their incomes within the actual spreads of income. The income gap here is severe and growing.  But, I want to look at the charts the BBC made to illustrate its points.

The most important is this line chart, which shows the income level and how it fits among the percentages of the population.

Are things lining up? It's tough to say.
Are things lining up? It’s tough to say.

I am often in favour of minimal axis lines and labelling. Too many labels and explicit data points begin to subtract from the visual representation or comparison of the data. If you need to be able to reference a specific data point for a specific point on the curve, you need a table, not a chart.

However, there is utility in having some guideposts as to what income levels fit into what ranges. And so I am left to wonder, why not add some axis lines. Here I took the original graphic file and drew some grey lines.

Better…
Better…

Of course, I prefer the dotted or dashed line approach. The difference in line style provides some additional contrast to the plotted series. And in this case, where the series is a thin but coloured line, the interruptions in the solidity of the axis lines makes it easier to distinguish them from the data.

Better still.
Better still.

But the article also has another chart, a bar chart, that looks at average weekly incomes across different regions of the United Kingdom. (Not surprisingly, London has the highest average.) Like the line chart, this bar chart does not use any axis labels. But what makes this one even more difficult is that the solid black line that we can use in the line charts above to plot out the maximum for 180,000 is not there. Instead we simply have a string of numbers at the bottom for which we need to guess where they fall.

Here we don't even a solid line to take us out to 700.
Here we don’t even a solid line to take us out to 700.

If we assume that the 700 value is at the centre of the text, we can draw some dotted grey lines atop the existing graphic. And now quite clearly we can get a better sense of which regions fall in which ranges of income.

We could have also tried the solid line approach.
We could have also tried the solid line approach.

But we still have this mess of black digits at the bottom of the graphic. And after 50, the numbers begin to run into each other. It is implied that we are looking at increments of 50, but a little more spacing would have helped. Or, we could simply keep the values at the hundreds and, if necessary, not label the lines at the 50s. Like so.

Much easier to read
Much easier to read

The last bit I would redo in the bar chart is the order of the regions. Unless there is some particular reason for ordering these regions as they are—you could partly argue they are from north to south, but then Scotland would be at the top of the list—they appear an arbitrary lot. I would have sorted them maybe from greatest to least or vice versa. But that bit was outside my ability to do this morning.

So in short, while you don’t want to overcrowd a chart with axis lines and labelling, you still need a few to make it easier for the user to make those visual comparisons.

Credit for the original pieces goes to the BBC graphics department.

Thanksgiving Side Dishes

American Thanksgiving meals often feature elaborate spreads of side dishes. And everyone has a favourite. A common theme around the holiday is for media outlets to conduct surveys to see which ones are most popular where. In today’s piece we have one such survey from pollster YouGov. In particular, I wanted to focus on a series of small multiples maps they used to illustrate the preferences.

Big splashes of colour do not necessarily make for a great map
Big splashes of colour do not necessarily make for a great map

I used to see this approach taken more often and by this I hope I do not see a foreshadow of its comeback. Here we have US states aggregated into distinct regions, e.g. the Northeast. One could get into an argument about how one defines what region. The Midwest is one often contested such region—I have one post on it dating back to at least 2014.

Instead, however, I want to focus on the distinction between states and regions. This small multiples graphic is a set of choropleth maps that use side dish preferences to colour the map. Simple enough. However, the white lines delineating states imply different fields to be coloured within the graphic. Consequently, it appears that each state within the region has the same preference at the same percentage.

The underlying data behind the maps, at least that which was released, indicates the data is not at the state level but instead at the regional level. In other words, there are no differences to be seen between, say, Pennsylvania and New Jersey. Consequently, a more appropriate map choice would have been one that omitted the state boundaries in favour of the larger outlines of the regions.

More radically, a set of bar charts would have done a better job. Consider that with the exception of fruit salad, in every map, only one region is different than the others. A bar chart would have shown the nuance separating the three regions that in almost all of these maps is lost when they all appear as one colour.

I appreciate what the designers were attempting to do, but here I would ask for seconds, as in chances.

Credit for the piece goes to the YouGov graphics team.

Food Flows Connect Counties

For my American audience, this week is Thanksgiving. That day when we give thanks for Native Americans giving European settlers their land for small pox ridden blankets. And trinkets. Don’t forget the trinkets. But we largely forget about the history and focus on three things: family, food, and American football. Not necessarily in that order.

But this week I am largely going to want to focus on the food.

Today we can look at a graphic coming from a team of researchers at the University of Illinois who examined the flows of food across the United States, down to the county level. It helped produce this map that shows the linkages between counties.

Oh look at that Mississippi River trail
Oh look at that Mississippi River trail

To be sure, the piece uses some line charts and other maps to showcase the links, but the star is really this map. But aside from its lack of Alaska and Hawaii, I think it suffers from one key design choice: leaving the county borders black.

The black lines, while thin, compete with the faint blue lines that show the numerically small links between counties. Larger trade flows, such as those within California, are clearly depicted with thicker strokes that contrast with the background political boundaries of the counties. But the light blue lines recede into the background beneath the borders.

I wonder if a map of solid, light grey fills and white county borders would have helped showcase the blue lines and thus trade flows a little bit better. After all, the problem is especially  noticeable in the eastern half of the United States where we have much geographically smaller counties.

Hat tip to friend and former colleague Michael Schaefer for sharing the article in question.

Credit for the piece goes to Megan Konar et al.

More Pub Trivia Scores

Next week is Thanksgiving and for me that means no pub trivia next week. So ahead of a two-week gap, here are our latest (and greatest?) in trivia scores. We won some, we lost some. And we definitely blew some. The key, as always, remains score points before music. Because we do not know music.

At best an unsteady performance…
At best an unsteady performance…

Credit for this piece goes to me.

The Shifting Suburbs

Last we looked at the revenge of the flyover states, the idea that smaller cities in swing states are trending Republican and defeating the growing Democratic majority in big cities. This week I want to take a look at something a few weeks back, a piece from CityLab about the elections in Virginia, Kentucky, and Mississippi.

There’s nothing radical in this piece. Instead, it’s some solid uses of line charts and bar charts (though I still don’t generally love them stacked). The big flashy graphic was this, a map of Virginia’s state legislative districts, but mapped not by party but by population density.

Democrats now control a majority of these seats.
Democrats now control a majority of these seats.

It classified districts by how how urban, suburban, or rural (or parts thereof) each district was. Of course the premise of the article is that the suburbs are becoming increasingly Democratic and rural areas increasingly Republican.

But it all goes to show that 2020 is going to be a very polarised year.

Credit for the piece goes to David Montgomery.

Erasing Culture One Tomb at a Time

As many of my readers know, I have a keen interest in genealogy. And for me that has often met spending hours—far too many hours—wandering around cemeteries attempting to find memorials to ancestors, links to my history, a context to that soil from a different time.

But if you live in Xinjiang or more broadly western China, and you’re not Han Chinese, you probably don’t have that luxury. The Uighurs, a Turkic Muslim people native to that part of Asia, have long been oppressed by the Chinese central government. Most recently they have been in the news after scholars and leading figures have “disappeared”, after news of re-education and concentration camps (though thankfully I have read nothing of industrialised death camps).

Instead, now Chinese authorities are destroying mosques (not news), but also now cemeteries, as this article in the Washington Post explains.

That's a lot of empty space. Well done, Beijing.
That’s a lot of empty space. Well done, Beijing.

The piece just uses some simple before and after photography to visualise its point. Sadly it does it to great effect.

I forget who originally said it, but someone once said that we all die, each of us, two deaths. The first time is when we die and our buried in the ground. The second and final time is when the last person who remembers us forgets us.

And we are now watching thousands of Uighurs in western China die for the second and final time.

Credit for the piece goes to Bahram Sintash.

Armistice Day

Yesterday was Armistice Day, a bank holiday hence the lack of posting. So I spent a few hours yesterday looking at my ancestors to see who participated in World War I. It turned out that on my paternal side, my one great-grandfather was too old and the other was both the right age and signed up for the draft, but was not selected.

And so the only two that served were my maternal great-grandfathers. One served a few months in the naval reserve towards the end of the war. My other great-grandfather served for a year, a good chunk of it in France. This I largely knew from my great aunt, who had told us stories about how he had told her about blowing up bridges they had just built to prevent Germans from capturing them. And then how after the war he served as military police, arresting drunk American soldiers in France. But I had never realised some of the documents I had collected told more of the skeletal structure like units and ranks. Consequently, I decided to make this graphic.

All the timelines
All the timelines

Credit for the piece goes to me.

Hoyle’s House

John Bercow is no longer the British Speaker of the House. He left office Thursday. Fun fact: it is illegal for an MP to resign. Instead they are appointed to a royal office, in Bercow’s case the Royal Steward of the Manor of Northstead, that precludes them from being an elected MP. Consequently the House of Commons then had to elect a new Speaker.

For my American audience, despite the same title as Nancy Pelosi, John Bercow had a very different function and came to it in a very different fashion. First, the position is politically neutral. Whoever the House elects resigns from his or her party (along with his or her three deputies) and the political parties abide by a gentlemen’s agreement not to contest the seat in general elections. (The Tories were so displeased with Bercow they were actually contemplating running somebody in the now 12 December election to get rid of him.) Consequently, the Speaker (and his or her deputies) do note vote unless there is a tie. (Bercow actually cast the first deciding vote by a speaker since 1980 back in April.)

Because the position is politically neutral, all MPs vote in the election and debate is chaired by the Father of the House, the longest continuously serving MP in the House. Today that was Ken Clarke, one of the 21 MPs Boris Johnson booted from the Tory party for voting down his No Deal Brexit and who is not standing in the upcoming election. The candidates for Speaker must receive the vote of 50% of the House. And so they are eliminated in successive votes until someone reaches 50% of the total votes cast, though not all MPs cast votes, since some have already started campaigning. (Today there were 562, 575, 565, 540 votes per round.)

Notably, today’s vote occurs just days before Parliament dissolves prior to the 12 December election. Bercow, who chose to retire on 31 October, essentially ensured that the next Parliament will have a Speaker not chosen what could well likely be a pro-No Deal Brexit, one of the things which the Tories have against him.

So all that said, who won? Well I made a graphic for that.

A very different accent will occupy the big green chair.
A very different accent will occupy the big green chair.

Credit for the piece goes to me.

UK–Narnia Border

Yesterday the United Kingdom was supposed to leave the European Union. Again. Boris would rather be dead in a ditch. But he’s neither dead nor in a ditch. And the UK is still in the EU. So let’s enjoy the moment and reflect on this xkcd piece from the other day. And then enjoy the weekend.

But what about the UK–Shire border? Or UK–Westeros?
But what about the UK–Shire border? Or UK–Westeros?

Credit for the piece goes to Randall Munroe.

Americans Can’t Kick the Auto Habit

After looking this week at the growth of the physical size of cities due to improvements in transport technologies, the increasing density of cities, and then the contribution of automobile (especially personal cars) to carbon dioxide emissions, today we look at a piece from the Transport Politic comparing US and French mass transit ridership to see whether the recent decline in US ridership is inevitable or a choice made by consumers and policymakers. Spoiler: it’s not inevitable.

The article makes use of a few graphics and an interactive component. The lead-in graphic is a nice line chart that runs with the spaghetti nature of the graphic: lots of line but only two are really highlighted.

The French are definitely better than the US here.
The French are definitely better than the US here.

Light grey lines and light blue lines encode the US and French cities under study. But only the lines representing the averages of both the US and France are darkly coloured and in a thicker stroke to stand out from the rest. Normally I would not prefer the minimum of the y-axis being 50%, but here the baseline is actually 100% so the chart really works well. And interestingly it shows that prior to the Great Recession, the United States was doing better than France in adoption of mass transit, relative to 2010 numbers.

But then when you directly compare 2010 to 2018 for various US and French cities, you get an even better chart. Also you see that French cities reclaim the lead in transit growth.

A lot of declines on this side of the pond.
A lot of declines on this side of the pond.

These two static graphics, which can each be clicked to view larger, do a really great job of cutting through what some might call noise of the intervening years. I do like, much like yesterday’s post, the comparison of total or aggregate ridership to per capita numbers. It shows how even though New York’s total ridership has increased, the population has increased faster than the ridership numbers and so per capita ridership has declined. And of course as yesterday’s post examined, in the States the key to fighting climate change is reducing the number of people driving.

What I cannot quite figure out from the graphic is what the colouration of the lines mean. I thought that perhaps the black vs. grey lines meant the largest cities, but then LA would be black. Maybe for the steepest declines, but no, because both LA and Boston are grey. I also thought the grey lines might be used when black lines overlap to aid clarity, but then why is Boston in grey? Regardless, I like the choice of the overall form.

But where things go really downhill are the interactive charts.

Just what?
Just what?

Talk about unintelligible spaghetti charts. So the good. The designer kept the baseline at 100% and set the min and max around that. After that it’s a mess. Even if the colours all default to the rainbow, the ability to select and isolate a particular city would be incredibly valuable to the user. Unfortunately selecting a city does no such thing. All the other cities remain coloured, and sometimes layered atop the selected city.

I would have thrown the unselected cities into the greyscale and let the selected city rise to the top layer and remain in its colour. Let it be the focus of the user’s attention.

Or the designer could have kept to the idea in the first graphic and coloured American cities grey and French cities light blue and then let the user select one from among the set and compare that to the overall greyed/blued masses and the US and French averages.

Overall, it wasn’t a bad piece. But that final interactive bit was questionable. Unfortunately the piece started strong and ended weak, when the reverse would have been preferable.

Credit for the piece goes to Yonah Freemark.