Mapping the Densification of Cities in England & Wales using the 2011 Census

Design01_ResidentialEmploymentDensity_EngWales_lowres

UK cities have been undergoing significant change over the last decade, and the 2011 census data provides a great basis for tracking current urban structure. I’ve mapped population and employment density for all of England and Wales in 2011, using a 1km2 grid scale approach-

Design01_ResidentialEmploymentDensity_EngWales_lowres

The main themes that emerge are the dramatic intensification of London, high densities in some medium sized cities such as Leicester and Brighton, and the regeneration of the major northern conurbations, with Manchester and Birmingham as the largest employment hubs outside of London.

Mapping all of England and Wales together is a useful basis for considering city-regions and their connections (note Scotland has not yet published census 2011 employment data and is not mapped). Certainly this is a major theme in current policy debates grappling with the north-south divide and proposed high-speed rail links. I’ll be looking at densities in relation to network connections in future posts as this topic is part of ongoing research at CASA as part of the MECHANICITY project.

It is also possible to directly map changes in density between using the same visualisation approach (note the grid height describes density in 2011, while colour describes change in density between 2001-2011)-

Population Density Change 2001-2011

The change map really highlights the pattern of city centre intensification combined with static or marginally declining suburbs in England and Wales. This trend was discussed in a previous post. The two statistics of peak and average densities reinforce the city centre versus suburbs divide, with peak density measurements growing much more than average densities. But the peak density statistic is somewhat unreliable (such as in the case of Birmingham/West Midlands) and we will be doing further work at CASA to define inner cities and produce more robust statistics of these trends.

 

Notes on the Analysis Method-

The density values were calculated from the smallest available units- Output Area population and Workplace Zone employment data from the 2011 census. This data was transformed to a 1km2 grid geography using a proportional spatial join approach, with the intention of standardising zone size to aid comparability of density measurements between cities. The transformation inevitably results in some MAUP errors. These are however minimised by the very fine scale resolution of the original data, which is much smaller than the grid geography in urban areas.

The workplace zone data is a very positive new addition by the Office for National Statistics for the 2011 census. There is a lot of new interesting information on workplace geography- have a look at my colleague Robin Edward’s blog, where he has been mapping this new data.

Defining city regions is another boundary issue for these statistics. I’ve used a simple approach of amalgamating local authorities, as shown below-

CityRegionBoundaries

 

 

World City Living and Working Densities: Poles Apart?

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One of the most recognisable visualisation techniques used by LSE Cities in the Urban Age publications is the 3D density map- an intuitive and engaging way to represent built form, and enable comparison of very different city environments across the globe. I’ve been producing 3D density maps in my own research for around five years now, and so it was a nice challenge to produce the 3D density maps for this year’s Urban Age conference, the Electric City in London. In this post I focus on the contrasting densities in three leading world cities- London, New York and Hong Kong- with the added twist that both residential and employment densities are mapped for comparison.

Higher urban densities can facilitate more sustainable travel patterns, improve service delivery efficiency, reduce building energy use and promote urban vitality. These advantages depend of course on good urban planning to minimise congestion and pollution problems. High density mixed-use development is central to the compact city planning movement, and remains a foundation of sustainable planning policy today. Here we map the number of residents in each square kilometre of a 100 by 100 kilometre region for London, New York and Hong Kong. Lower urban densities apply to suburban-like neighbourhoods, while high densities generally represent medium or high rise buildings clustered on a tight urban grid.

The city that stands out in the mapping is Hong Kong, with its extremely high residential densities exceeding 110,000 people per km2. Here planners have responded to scarce land availability with very tall (over 30 storeys) high-density development. Scarce land has also influenced the development of New York City, where Manhattan densities peak at 59,000 people per km2. London in comparison is much lower density. The heritage of suburban housing and generous greenspace has created a residential culture at half the density of New York and a quarter the density of Hong Kong. Despite current intensification in London, residential densities remain a world away from other global cities.

Where people live is not however the only perspective needed to understand urban density. We can also examine employment densities for an important point of comparison (both residential and employment maps are at the same scale). Taller spikes in the employment maps represent higher numbers of jobs concentrated in business centres. London, New York and Hong Kong feature very intensive central employment clusters. The highest peak of over 150,000 jobs per km2 is in Midtown Manhattan. London is surprisingly close behind at over 140,000 jobs per km2, concentrated in the City of London and the West End. Hong Kong peaks at 120,000 jobs per km2 in Central (note the Hong Kong survey data is less comprehensive and may underestimate peak densities). These intense spikes represent very strong agglomeration economies, where financial and business services and creative industries cluster together to access labour markets, share fast-changing information and engage in face-to-face interaction with clients, customers and partners. Despite living in an age of instant telecommunication, proximity is still critical for many world city business activities.

The extreme employment density peaks are indicative of economic success in these world cities. Demand for office space is so stong that developers get sufficient returns to build high and businesses use their space more intensively. Central employment clustering also means these cities are dominated by public transport rather than car travel (particularly Hong Kong). On the other hand the divergence of living and working densities can signify a lack of integration between living and working locations. London is very polarised between its low density living and high density working environments. This contributes to the long distance and long duration commuting travel for many Londoners (recent surveys find an average one-way commute times for Londoners of 38 minutes). New York has a better integration of living and working locations (average commutes are around 31 minutes). Hong Kong appears to have the closest integration of living and working spaces, though unfortunately commuting time survey data is not available to test this.

The analysis here supports the medium-rise inner-city residential intensification that the London Plan prescribes to improve the balance of urban functions, and increase accessibility for residents and businesses. The gap in residential densities between London and many world cities is so large that modest intensification can be achieved while keeping London’s distinct character, providing development is on the much remaining brownfield land rather than London’s treasured greenspaces.

Another interesting thought is whether the highly concentrated office clusters we see in London and New York will continue to be the way most businesses operate in the future. Greg Lindsay gave a good talk last week on how businesses are changing the way they use work space towards more shared and flexible environments that will likely be less space demanding.

To see more detailed analysis of sustainability trends in many more world cities from the Urban Age conference see the Electric City conference newspaper.

A Tale of Tech City: the future of Inner East London’s Digital Economy

TechCity

Earlier this month Demos published a fascinating report on the hot topic of London’s “Tech City” cluster, which has been promoted by the government as a key growth pole for the UK. The report authors Max Nathan, Emma Vandore and Rob Whitehead, put the Inner East London cluster in the context of similar phenomena in New York and Berlin; and get their hands dirty with some in-depth data analysis and face-to-face interviews of entrepreneurs. Policy recommendations are then made for the best way forward.

There have been some cool efforts at mapping the Silicon Roundabout Shoreditch/Old Street cluster from Wired UK, and from Tech City Map using social networking connections. A more traditional robust approach was taken in this report of using the various business survey datasets to measure firms and their activities. The scale of the cluster (defined more widely to include Clerkenwell, Shoreditch and Hoxton) was found to be larger than previously thought, at around 3,200 digital economy firms and 48,000 jobs, with these industries becoming increasingly important for the London economy.

I got involved with the project doing some density mapping of the core industries that make up the cluster: ICT firms and creative industry firms. The key message that comes from such mapping is that the cluster is embedded in a digital-creative corridor stretching from the West-End and Soho through Clerkenwell and on to Shoreditch.

From a spatial perspective, the cluster is about the Jane Jacobs type urban diversity fusion of IT and creative industries, very similar to Silicon Alley in NYC. High profile success stories like LastFM (music, digital broadcasting and social networking crossover) and Unruly Media (advertising, social network and analytics crossover) are prime examples of this integration. This tech-creative fusion clearly distinguishes the Inner London cluster from the IT software/hardware concentrations you get in Silicon Valley, or in the “Western Wedge” around Heathrow.

A high profile policy objective from the UK government has been to link the Inner East London cluster to future opportunities at the Olympic Park. The Demos report convincingly argues that the focus should rather be on the current cluster, enhancing funding opportunities, skills and growing new businesses. Moving to the Olympic Park is problematic in terms of it lacking the history, creativity and ‘vibe’ of the current cluster. The absence of creative and IT firms around Stratford is apparent in the above maps. Opportunities in the Olympic Park are more likely to suit larger established IT and engineering firms attracted to new high-spec offices.

That’s not to say the Olympic Park can’t have a role however. The firm interviews in the Demos report identified the lack of skilled workers being a big issue, at all levels including graduates:

There just aren’t enough computer scientists in the uk. And we need computer scientists, we don’t need – what do they call it – ICT trained people. We need real computer scientists who do software engineering and programming. No education coupled with visa restrictions is not a particularly good combination.

So apart from lifting the current counter-productive visa restrictions in the UK, there’s a clear role for universities in training more computer scientists with the right skills to succeed in these growing industries. This is what London universities are now in the process of doing at the Olympic Park, with new campuses planned and initiatives such as the UCL-Imperial smart cities institute in the pipeline. Your very own CASA is already involved in training graduates with smart cities skills. Smart Cities industries can themselves be viewed as a built environment-engineering-ICT fusion, likely complimentary to creative industry clusters.

 

 

The Evolving Business Geography of Greater London

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I presented at the CASA Seminar Series yesterday on the topic of business centre specialisation in Greater London. The discussion drew on previous research into knowledge economy agglomeration and urban property markets.

The analysis showed how the diversity and restricted growth of West London underpins the current extremely high rents, whilst the greatly densified City of London faces oversupply with lower demand for financial services after the economic crises. The recent revival of centres in the City Fringe is based on creative industries and IT/new media, and it’s hoped similar recipes will work for future business centres at Kings Cross and Stratford.

 

The slides can be viewed here: