The Urban Fabric of English Cities

[now updated, thanks to @udlondon - scroll to bottom of page]
Inspired by some mapping in the US by Seth Kadish, the availability of new GIS open data, and the fact that I love looking at patterns of urban form, structure and density, I have created a comparative graphic showing the building footprints of nine English cities, with London at the centre (just because it's biggest). I have done this in a very simple way, with all cities mapped at a scale of 1:125,000 in the full size versions (which are massive), plus one small scale bar and a little explanatory text. Here's what it looks like:

The urban fabric of English cities (black/red, medium res)

This graphic does a good job - in my view - of demonstrating the compactness or otherwise of the cities in question. It also illustrates how tightly-bounded some places are and how under-bounded others are. For example, Liverpool is very dense and compact in contrast to Leeds but this really is a boundary effect because the size of the local authorities differs so much. The urban area of 'Liverpool' extends far beyond the boundaries of the local authority area, which is what I show above. I wanted to compare the local authority areas rather than the wider city-region because I wanted to highlight this boundedness issue and compare like with like in terms of formal administrative areas. London is obviously a bit different so I've shown the 33 constituent parts of Greater London.

Take a closer look at the graphic by clicking on the two larger images below - one in white and one in black. They are both just a bit bigger than A0 paper size in their full size versions in the zipped folder below so if you want to take a really close look, download them. I've also uploaded smaller-sized versions in the same folder. I deliberately didn't include more information on the graphic itself, but at the bottom of the post you'll see the population of each city in 2011 (which relates to the individual city images), plus its urban area and metropolitan area population. The population of Greater London in 2011 was 8.2 million (compared to 4.4 million for the other cities shown). The cities I selected are the English members of the Core Cities group, which now also includes Glasgow and Cardiff.

Click here for a full screen white version

Click here for a full screen black version

Download a zipped folder with black and white versions in different sizes.

Update: the @udlondon people got in touch via twitter to show their attempt at fitting the core cities inside the London boundary - as below - so this inspired me to try the same with the original data. The first image below is the original @udlondon artwork and the next one is my attempt using GIS. Finally, as a reminder that nothing is ever really new, I have added a similar map which we found as part of the JR James urban image archive which we launched last year. This version has 13 different cities.

A manual approach to GIS!

My attempt at the same thing, using QGIS - full size

Some of the boundaries were a bit different in those days

City	Population	Urban area	Metropolitan area
Birmingham	1,085,400	2,440,986	3,683,000
Bristol	428,200	587,400	1,041,000
Leeds	751,500	1,499,465	2,302,000
Liverpool	466,400	816,216	2,241,000
Manchester	503,100	2,240,230	2,556,000
Newcastle	280,200	879,996	1,599,000
Nottingham	305,700	666,358	1,543,000
Sheffield	552,700	640,720	1,569,000

Totals: the population of the 8 city local authority areas is 4.4 million, for their urban areas it is 9.8 million and for their metropolitan areas it is 16.5 million. I may compare metropolitan areas next time, but mapping this is a little more time consuming.

Some thoughts on mapping spatial patterns of deprivation

In my research into the geography of deprivation across the UK, I frequently use maps to illustrate the spatial patterns associated with the areas identified as 'least' or 'most' deprived according to official indices such as the Scottish Index of Multiple Deprivation or the English Indices of Deprivation. Lots of other people do similar kinds of things, including mapping gurus such as Oliver O'Brien from UCL (his work is much nicer). A recent example is shown below, which I also tweeted this week. It's difficult to know exactly how people will interpret such maps, particularly when they are only seeing them on twitter without much in the way of context being provided, so this short blog fills some of the gaps and discusses some wider issues.

Full size version

In previous academic papers (e.g. Urban Studies, 2009; Regional Studies, 2012; Local Economy, 2012) I've written about deprivation quite a bit, and on the need for the debate to centre not just on 'deprived' areas but more widely upon the wider dynamic of socio-spatial inequality. It's a shame that the focus is still very much on 'poor' or 'deprived' areas so in an attempt to draw attention to the urban inequalities which exist across the UK I attempt to illustrate the socio-spatial disparities within different cities. I also did this in a report on Sheffield from 2011 where I tried to draw attention to the socio-spatial inequalities within English cities, as shown below. It's not that concentrated deprivation isn't a problem (far from it) but rather that it's part of something much bigger.

Full size version

These kinds of maps do draw attention to the general issue but of course they can lead to all sorts of other conclusions and claims because as we know, maps are an abstraction from reality and they do not represent an absolute 'truth'. These maps simply colour small areas within cities according to how they are classified by a government metric which attempts to say how 'deprived' places are. This may be a dubious practice in many respects, but it is woven into the fabric of how places are understood in a policy context and how problems are defined. It's important that we understand what this kind of mapping allows us to say and what it does not. Some of this is covered on the 'What does it all mean' tab of my Scottish Index of Multiple Deprivation 2012 map site, but I want to make a few more points here...

1. Colours. They are not intended to match up to any political party but some people inevitably make such inferences. The maps say nothing about the causes of the patterns, or who is responsible for them. But it doesn't stop people from talking about it and that's no bad thing. There is a lot more that could be said about colour choice but I'm going to leave it there for now.

2. The trouble with choropleth maps. Maps shaded according to some value (such as deprivation rank) present a misleading picture in a number of ways but two important ones stand out here: a) not all people in the area are 'deprived' or 'non-deprived'. This is the classic 'ecological fallacy' issue at work - the third paragraph here says more about that; and b) the shaded zoned themselves cover much wider areas than people actually live in so a big blue or red area gives the impression of a lot of something, when in fact the population of larger spatial units is similar to the smaller ones (as it often is with LSOAs or Data Zones in the examples above). 

3. The sometimes arbitrary nature of local authority boundaries. Places like Leeds are often said to be 'overbounded', whereas Manchester is 'underbounded'. This means that the local authority boundary either extends beyond the core urban area or it doesn't include much of it at all. So, in the cases of Manchester and Liverpool above if you were to extend the boundary of the map you would see more areas that are not so deprived. However, the point here is that local authorities have to deal with the financial, social and spatial implications of these patterns. What happens beyond the boundary is not part of their remit - even if it does impact upon them. The boundaries may be arbitrary in some respects but they have very real implications.

4. Why not take a different approach? A good idea, and one that Oliver O'Brien in particular has been very successful with. If we only look at where people actually live then we get a more realistic (but still not 100% accurate) picture of the spatial patterns associated with deprivation. This can be done using dasymetric mapping, where we assign the attributes of areas to individual features. This isn't a perfect definition, and the technique itself can lead people to assume a higher level of accuracy than can actually be obtained from the underlying data but it has advantages over standard choropleth maps in relation to depicting the places where people actually live or work. See also Neal Hudson's London tenure map in this style. The new OS Open Data VectorMap District buildings layer for Great Britain allows us to do this, so I've produced an example map for Glasgow based on the one in the first image above. This time you can only see the areas where there are buildings (though many are not residential properties).

Full size map

Is the map above more 'truthful' than the normal choropleth? Probably not. However, this is all irrelevant if we aren't concentrating on the underlying patterns we're trying to draw attention to in the first place. The point is that in cities like Liverpool, Manchester and Glasgow the high levels of deprivation/poverty/disadvantage sit in stark contrast to areas at the other end of the scale. Also, places that we think of as 'deprived' are often far from it - as Peter Matthews might also argue. It's this kind of inequality which I'm attempting to highlight with my mapping - though I do of course like a nice looking map (I've also produced more than a few stinkers in my time). The point of all this? I hope that these maps can start a conversation about the underlying issue. I'll end with an extract from my 2012 Regional Studies paper on the issue...

Google Fusion Tables

A short post today about the wonderful Google Fusion Tables. It may sound baffling, but Fusion Tables are basically a service (provided by Google, obviously) that allows you to manage and map large databases 'in the cloud', as they say. In plain speak, you can upload large tables of data and display them and map them and share them. For someone like me who is into mapping data, this is great because all you need to do is get your data into kml format. This can be done with normal GIS software like ArcGIS but the best way I have found is to use shpescape.



The example above is just something I created a couple of years ago in ArcGIS and then recently uploaded to Fusion Tables. It's a 'tile finder' for Ordnance Survey data so you can figure out which 20km tile you need to get based on which area you are interested in. This is not the point here though - I'm just showing how you can get data into google map format very easily.

If you work with lots of data on a regular basis - and particularly any mappable data - you should take a look at Fusion Tables...

OS OpenData - It's Here!

So, Ordnance Survey today unveiled their new 'OS OpenData' service, where anyone can download high quality OS datasets for viewing or for use in a GIS. Personal and commercial re-use is allowed, though the largest scale datasets (e.g. MasterMap) are not included in this 'free' service. Nonetheless, it's an excellent development. The official government document has more details, and the data download section is now live. In recognition of this historic day, I've done a quick video tour of the new service. I'll blog on something different next time...

OS OpenSpace - free web mapping

Following on from the subject of the previous post on Ordnance Survey, I've been experimenting with their excellent new OpenSpace service, launched in January. The OS OpenSpace API is free to access and lets developers create web applications and online projects with Ordnance Survey maps.

Put simply, you can now easily make a map with OS data and put it on your website. On blogger it can be a bit tricky, but overall it's not that difficult and there are many options for customisation. The map below is just an example - it is fully interactive. I made it quickly using the web-map builder. (For those of a technical persuasion, I just pasted in some iframe code on blogger - the actual html file is on my university server.) I may do more with this in future but for the time being this is it...

Ordnance Survey Data - A Revolution?

Following the news some time ago that most Ordnance Survey data (if not all - still waiting for details) is to be made available free of charge for re-use by personal and commercial users, the GI fraternity is abuzz with anticipation. I am also pretty excited about this development since it will make working with geographic data and using GIS in the United Kingdom much easier. It should also increase the number of users, as SalfordGIS point out.

The current understanding is that from April 1, 2010 several OS datasets (e.g. 1:50,000 colour raster) will be made freely available. What are the implications of this? Just some thoughts...

• Anyone will be able to download and print original OS maps, free of charge
• Anyone will be able to use OS data to derive new maps - previously this was forbidden
• GIS users will use data in new and innovative ways
• GIS consultants will increase in number
• In general, many good things will happen and geographic knowledge will increase
  

Much more will be written on this in the media in the coming weeks and there is no doubt it is an exciting time if you are in any way involved in the world of geographic information in the United Kingdom.

The future is full of possibilities!