Saturday, 19 November 2016

Great Britain: Population 7.4 billion

My recent post on the EU's new global population density datasets got me thinking once again about the issue of population density across the world - and how it varies hugely. Some people think England is particularly crowded and some would probably say that Great Britain as a whole is quite a tightly packed little island. But of course this is all relative. I was reminded of this recently when I discovered that the Philippines is now on Google Street View. Since I had a few spare moments and because my brother lives in Manila I went for a little tour around the city, and was struck by the sheer density of it. As it turns out, Wikipedia and other sources say the City of Manila is the most densely populated city on earth, with over 41,000 people per square kilometre. This is followed by another Metro Manila area (Pateros), at over 30,000, and then Dhaka in Bangladesh at over 28,000. Where am I going with this? Using these figures as a reference point, I decided to see whether the entire population of the world - currently about 7.4 billion - could fit in the island of Great Britain. The answer is yes. Some maps and a few words below to help explain...

I've cut out a chunk of Manila and tiled it over GB - somewhat bigly

If you scale things a little more closely to the real world, you begin to get a sense of what this kind of density would look like on the ground - and remember that in some parts of the world people do live at these densities. Just not in the South West of England and time soon, thankfully.

I believe getting planning permission for this might be an issue

To the other end of the country now, around the far north east corner of Scotland, including Wick (current population about 7,000). Not much room to breathe here. There isn't much room left for roads or train lines or parks or anything else, so day to day life might be just a little complicated. 

Transport, waste, communications and a few other things would be a bit tricky

There are about 7,400,000,000 people in the world now, according to current best estimates, and the land area of the island of Great Britain is about 210,000 square kilometers. The maps here don't have lochs and lakes cut out but my calculations do take this into account. So, this gives us a population density of 35,238 people per square kilometre if we had to accommodate the whole world in Great Britain.  Remember that is a lower density than the City of Manila (i.e. the inner part of Manila with a population of 1.7 million, rather than the whole of Metro Manila - with 13 million). Let's look at a few more maps now.

Merseyside and surrounding area 

Central London, with a slighly wonky looking Thames

For reference, there are about 300 people per square kilometre in Great Britain at present. There are about 5,500 people per square kilometre in London and about 6,300 in Tokyo. New York City has a population density of about 11,000 and Paris is quite tightly packed, at about 21,000 per square kilometre (for the 20 arrondissements). Manhattan has about 26,000 people per square kilometre.

There is loads of stuff on the internet about this general topic, including the excellent Per Square Mile by Tim De Chant. The most densely populated country is Macau, at just over 21,000 people per square kilometre. If all this metric stuff is confusing, then I can tell you that in imperial units the density needed to accommodate the world in Great Britain is about 90,000 people per square mile. No matter how you measure it, that's a lot. Even Manhattan only has 67,000 people per square mile.

The obvious question now of course is what we should do with the rest of the world. Turn it into a park? Nature reserve? Museum? I'm joking of course - there is also a more serious point here. I'm just trying to put some perspective on the issue of population density across the globe and how we measure it. It's tempting to look out the window or use our day to day lives to assess what's 'normal' - and of course this is natural. But when I've been looking more closely at the GHSL global population datasets recently I have been amazed at just how densely populated some cities are - as you can see a little bit from my previous blog post on the topic.

London and the surrounding area - not actually all that dense

Notes: okay, this was mainly just a little bit of fun but I did want to try to put it into perspective, not least because I'd also read a myth-buster piece by Simon Rogers and James Ball about the claim that everyone in the world could fit on the Isle of Wight. Here's the bit of Manila I used for the urban area in the maps above. I'm not seriously suggesting we concrete over Great Britain and attempt this so please don't send me hate mail about the green belt! Also, here's a piece from 2013 that does the same kind of thing, though not with Great Britain. Finally, and somewhat ironically since this was partly a procrastination thing, the 2013 piece was originally by Tim Urban of Wait But Why. His very amusing procrastination TED talk on YouTube now has over 4 million views.

Friday, 4 November 2016

The 435 Congressional Districts of the United States in one giant poster

In his last State of the Union Address, President Barack Obama called for an end to gerrymandering - the process of drawing political boundaries in a way that favours one party over another. I knew a bit about the topic from my time in the US, but I wanted to see what all 435 Congressional Districts looked like, so I ran off a set of maps. This was later picked up by WIRED* and shared quite widely. This week, I saw US elections guru Stephen Wolf had published a new shapefile of Congressional Districts which included the revised Florida, North Carolina and Virginia boundaries. I had a few extra moments due to something being cancelled at the last minute, so I ran off a set of maps and turned them into a gif and a poster. I shared the gif on twitter but am posting more material here in case anyone is interested. First of all, here's the massive poster with all 435 Congressional Districts, arranged alphabetically by state and District number.

Not to scale - it's about comparing shapes - bigger version

You should be able to click on the above image to see the labels more clearly. If you want to download a really gigantic version, have a look here for the 13MB, 16,527x16,841 pixel monstrosity. Shapes alone can't necessarily tell us whether an area is clearly 'gerrymandered' or not but it's fair to say that in some cases it's a pretty good sign!

I also created two gifs which animate through all 435 Districts at different speeds. The first one below is the one I previously shared on Twitter and the other one is a slightly slower version. The intention of the first was to leave just enough dwell time on each frame so that you can perceive the variety of shapes but also see all 435 in under a minute. In the second, I'm trying to allow more cognitive processing time.

It's supposed to be somewhat hypnotic

The first one is pretty fast, with only a tenth of a second for each Congressional District. The version below shows each District for half a second, so might be a little bit more useful but then again it takes longer to run through.

The definitive gerrymandering gif? Maybe not, but it's a quick summary

Here I have been experimenting with display techniques partly as a way of educating myself on an important subject but also partly to figure out what the best way of representing the data in an easily digestible way is. I also posted each of the individual frames from the gifs to a Google Drive folder in case anyone wants to use them.

I like the small multiple approach of the poster better in many ways because you don't have to wait to scroll through the images and also you can make visual comparisons between, say, frame 2 and frame 200 without having to wait for the gif to loop through to it. Also, you don't have to interact with it in the same way so I find it more accessible and actually made it this way so that it could be printed out as a large poster and used as a focal point for discussion and debate - which I think is one of the things maps can be very useful for.

Finally, here's the poster in two different colours. There's also a folder with all three versions in different sizes.

Does it look better or worse in green? Bigger version

A classier colour, I feel - bigger version

Here's the Obama 'gerrymandering' part - source

*The person who wrote that WIRED piece has since been 'moved on' owing to some sub-optimal journalistic practices but the piece remains online under an editorial note.