Does this map actually show every European town with over 1,000 residents?

Sometimes in my travels around the backwoods of the internet I spot a map so pleasing, one that does such a perfect job of telling a story, that it goes straight to the top of the list of things I plan to pontificate about as soon as I find a spare moment.

And then I start to wonder whether perhaps it might just be a bit too good to be true.

So it was with this beauty, posted to Reddit by user Sp33d3h. It uses a single red dot to show every town or city in Europe with a population of over 1,000. You can instantly see which bits of the UK are heavily populated, and which are relatively rural. You can see the way Europe’s population thins out the further you head north or east. You can see the Alps.

It’s lovely.

Click to expand.

It’s probably not right, though.

For one thing, the boundaries between countries are often just a little too well demarcated. You can see at a glance where Denmark ends and Germany begins; you can also spot the boundaries between Bulgaria and Romania, or Poland and Slovakia.

Rough national boundaries in blue.

Now, it’s possible that there’s some geological feature demarcating the boundary which means that urbanisation becomes much heavier on one side than the other – but the fact those boundaries (most of which are relatively recent inventions) are visible over such long distances suggests something else is going on. It looks like me like there’s a disconnect in the data – like it’s being collected in different ways in different countries.

Which, if you think about it, it obviously would be: literally nobody has the resources to go round counting all the settlements of 1,000 people or more across an entire continent. It’s all but certain that this map is collating datasets collected by other people, and national boundaries are the most likely place for one dataset to stop and the next begin.

One of the commenters on Reddit who’s examined the map on the Harvard website that provided the data for this one speculates that what we’re actually looking at is municipal or administrative boundaries. Except if we zoom in it’s not even clear that’s it, because here’s what you get in London:

Nope, no idea. Image: Harvard WorldMap.

I am reasonably familiar with all sorts of ways of chopping my city up into bits, and that doesn’t look like any of them. I have literally no idea what these units are. (Also, it’s not immediately obvious why the Greater London conurbation should really be a few dozen settlements rather than one big one.)

So – as pleasing as this map is it probably isn’t anything as useful as every European settlement of over 1,000 people.

That doesn’t mean we can’t tell anything useful from the map. The way the dots are distributed within countries is probably quite telling. So we can see, for example, that the most rural parts of Great Britain are in mid Wales, Scotland outside its central belt, and the far north west of England:

We can see that the fringes of France and Spain are generally more populated than the middle:

And that Scandinavia empties out, the further north you get:

But internationally, I fear, this map tells us little – or rather, we can’t tell when it is telling us something, and when it’s just a quirk of the data.

As much as I’d love to see a map which actually did what the one at the top of this post claims to, I fear that no such data set exists. I mean, how would you even begin to count every settlement that small?

For what it’s worth, here’s a map showing population density across Europe, using roughly county-sized lumps. Enjoy.