I read something recently that suggested good content had provocative titles, which on closer inspection boiled down to phrasing them in the form of a question. That way you can also get away with titles that are complete lies, but draw people in, such as "does Facebook poison orphans?". I think I may have a promising future ahead of me in tabloid journalism.
Anyway, back to the point. Have you ever noticed how Google maps at certain zoom levels displays some places but not others? Have you ever wondered how they decide which places to show? Well, okay, probably not, but I have, so let's have a look at that.
Note: all of this may be subject to change - I have no idea how frequently or in what way Google updates their maps, but I can say that I first noticed what I'm about to describe several months ago, and things don't seem to have changed at all in the meantime.
I first noticed something odd when looking at the UK at this zoom level. Here's a screen cap of what I'm seeing now, in case it changes.
At this zoom, Gmaps shows the names of only these places in the UK:
You might think that there's nothing particularly interesting about this list, but if you live in the UK you might be surprised to notice that the city of Birmingham is not in it. This, despite the fact that Birmingham is the second largest city in the UK by some way, with a population of 1,224,136. Here's some data to consider.
Source: The Geographist
So what's going on here? Gmaps might be showing the most populated places by county or regional area, but even then Birmingham is still the largest in its area, and Inverness doesn't even crack the top 10 in Scotland.
Google might also have ranked places based on how much physical space they occupy (a reasonable concept for a view from above) but I looked into this and unfortunately that data doesn't seem to be easy to get hold of. Perhaps because the actual boundaries of these places are difficult to measure? Regardless, Birmingham is still a contender for appearing on the map, considering how big it is, particularly compared with, say, Inverness.
It isn't until several zoom levels later that Birmingham finally appears, along with much smaller places like Hereford and Wrexham...
My limited expertise in geography starts to wane at this point, but let's take a look at another country just for interest. What about France? At the same zoom level, we see the following places.
Google seems to be doing much better in France, displaying the top ten and then nothing outside of the top fifty within twenty one cities. Clearly no problem here.
So what's going on with the UK?
If I'd found similar discrepancies in the France data I might be inclined to investigate a third country, but at this point I don't have much to go on. It's entirely reasonable to suppose that the algorithm Google Maps uses for which cities to display at different zoom levels is based on something sensible, and something likely determined automatically rather than manually. Perhaps a combination of generated output based on an even distribution of a manually input list of major population centres?
I'm of course completely guessing at this point, and there's not much use in that. After all this I'm left only with the same simple question I started with - does Google Maps know that Birmingham is the second largest city in the UK?