Thursday, 18 June 2020

Where is Scotland's pole of inaccessibility?

The first question you might be asking is 'what is a pole of inaccessibility'? Well, it typically refers to the furthest point from the coast - either at sea or on land. In this case, I've calculated Scotland's pole of inaccessibility using the coastline (Mean High Water mark) and arrived at a single, fairly accessible point a few miles from Braemar, in Glen Quoich. It's just over 41 miles from the sea and at an elevation of about 470 metres above sea level. It's almost slap bang in the middle of the Cairngorms National Park, as you can see below. This all began when Andy Arthur asked me an entirely different question on Twitter last night about dividing Scotland in two, but that's a different story with a different answer

UPDATE, 25 June 2020: a Braemar resident very kindly got in touch, went to the pole of inaccessibility (I provided accurate coordinates), and has taken some photos of it. Scroll to the bottom to see these.

Actually quite an accessible point, if you're keen

Where's the nearest coast to this point? Well, Dundee comes close and so does Montrose, but by my reckoning the nearest coast is just off Inverness (near the A96 and the big Tesco, since you asked). Nairn beach comes close as well though. In reality, as Colin Angus has pointed out, it's going to be more than one point but I chose Inverness because it's surely one of them, plus home town bias (EDIT: see bottom of post for the three closest points). From the centre of Braemar it's about three and a half miles to the point of inaccessibility. Here's how that looks on a national map (below) and some zoomed-in maps too. It should go without saying that this calculation is based only on what might be called 'mainland' Scotland for the purposes of this exercise - i.e. the calculation is based on the big landmass you see highlighted below in the first image.

The point furthest from the sea

Looks like you can walk pretty close to it

OS 20km tile N008, since you ask

To calculate this, all I did was load a detailed shapefile into QGIS, then I divided the Scotland file into separate polygons and extracted the 'mainland' polygon. Once I'd done that I just ran the 'Pole of inaccessibility' tool from the Processing toolbox and got the point you see here. I then did some buffering at single mile intervals to explore it a bit further, as you can see below - and above in the zoomed-in one.

The shading is 1 mile buffers - from the coast

The white lines are single mile buffers

By now, you might be thinking something like 'but how does this compare to the location of the geometric centroid of mainland Scotland'. Admit it, you definitely were thinking this. Well, the answer to that question is that it's just over 42 miles away to the south west, in between Loch Ericht and Blackwater Reservoir near Kinlochleven. See below for a couple of maps on this - and as always if you spot something iffy here or think this doesn't add up, feel free to get in touch. 

Amazing knowledge to impress your friends

The beating hearts of Scotland

I suppose the amazing thing about all this is that you didn't now how much you needed to know it until you knew it. I would say it's pointless information, but there are at least two points on the map above that provide evidence to the contrary. A little bit of map knowledge can't do us any harm, and you might even be able to use this to visit Scotland's pole of inaccessibility and then tell all your friends about it.

If you need a map of how to get there, see below.

There you have it - white lines are a mile apart

A short addendum here because I couldn't leave this without knowing where the closest coastal points were, based on the Mean High Water definition. It turns out it's by Inverness, the tidal part of the Tay to the north of Perth Harbour, and the tidal parts of the South Esk just by Montrose Basin. The circle in the map below has a 41.25 mile radius from the pole of inaccessibility shown above.
Yes, Perth has a harbour

Obviously, this is 'coast' by the official definition

This is the most 'coasty' of the coastal points

I'd begin from Inverness if I were you

Technical post-script
Despite spending literally quite a few minutes on all this, I couldn't figure out a way to calculate a pole of accessibility for Scotland that didn't treat the border with England as coast. Not that this really matters anyway because you can eyeball it and see that it's not in the south. I also manually checked it. But, this does mean that the internal buffer map above should be read in this context - i.e. the buffers from the border are obviously not from the coast. In order to show a bit more of this, I've taken the circle in the maps above and centred it roughly where I think the pole of inaccessibility is in the south of Scotland - somewhere around Hawick I suspect. If I had spent a lot of time on this, I might have been able to solve it but for the time being a manual check on this is all I need.

The border is not the coast, obviously

Here are some photos of Scotland's 'pole of inaccessibility' - with a pole marking the spot!
As I said above, these were sent to me by a very kind local resident, so I didn't travel here to take them but I hope to do so one day in the future. The pole of inaccessibility is at the edge of the Glen Quoich Caledonian pinewoods and birchwoods, as you should be able to see from the photos. It is surrounded by expanding woodlands, so the view will be very different in a few decades' time! (words provided by our friendly on-the-ground Braemar resident who lives less than 5km away from this point).

Looking south to Morrone
Looking southwest to Creag Bhalg

Looking northwest
Small Scots Pine

Here's the pole - looking at Caledonian pinewoods

Friday, 12 June 2020

City street patterns

This is a post about streets. Or roads. Or Avenues, Lanes, Gardens or Places, or even Ways. Giuseppe Sollazzo did this kind of thing already in an extremely clever and efficient way, and he's very much the inspiration here. But I wanted to revisit the topic for a variety of reasons, though mostly just curiosity - and sometimes that's enough. 

So, let's begin by looking at one of the 451 maps I made, of the UK's biggest new town (population now about 270,000).

Quite a few Close and Court and Hill ones 

As you can see, all I've done is colour the roads according to their designation as 'Road', 'Street', 'Way' and so on. The 'Other' category includes things like 'Close', 'Court', 'Hill', 'Crescent', 'Brae' and a few more, but there aren't enough colours for all of them. In Milton Keynes, and some other places, you also get streets with no second name, like where they are just called things like 'Downland' or 'Cavenham' or 'Garston'. I think that's because the local road namers refused to work pro bono. Okay, I'm really struggling to make this U2 joke work, sorry.

Anyway, I've done maps for 451 different locations across Britain using Ordnance Survey open data (the OS Open Roads layer). I then added some place names using a possibly-annoying whimsical font (Nanum Pen) and then added a colour bar legend along the bottom so you can tell what's what. Here's a map centred on Liverpool, which is a good example of the way in which 'Street' tends to be in more central, older locations. 

You can see Queens Drive here easily

The scale is the same on all maps - I used a 1:50,000 scale and you can see how far one mile is by looking at the scale bar in the bottom left of the images. they are mostly focused on individual towns and cities but in the case of London, for example, there are maps centred on specific areas, such as Kensington.

It's all Roads beyond here

Edinburgh (with its New Town, for example) and Glasgow (with its central grid pattern) are actually very interesting, so I've added them below.

Spot Holyrood Park

Look closely to see the M8 and M74, M77, M80

What about some other big towns and cities? The full set is in this online folder, but I've posted some more below for the time being. I've started with York, because it's not fair that it always ends up last on the list.

That's all there is to it, really. 

But I do think it gives us an interesting glimpse into lots of other things, like how the new towns were laid out, how some of our older and bigger towns and cities developed, and even things like density, connectivity, topography and so on. 

I'm fascinated by the shapes of towns and cities so that's how I got here, and if you've scrolled this far maybe you are too.