London Housing Market Report

I have converted the GLA’s London Housing Market Report from a quarterly document (last edition here) to a live resource on the London Datastore. It uses the Google Charts service via the googlevis R package, which allows you to create HTML straight from your own data rather than having to upload it to Google’s servers. While the use of Google Charts started out as a labour-saving device and hopefully will be over time, setting this up involved a lot of fiddling with Javascript to get the charts to display okay on the Datastore’s Drupal system. I’m grateful to Scott Day in the GLA’s GIS team for help with this aspect.

The great advantage of using Google Charts are that its layout and colour defaults are very good and where changes are required they are pretty easy to implement. I used to agonise excessively over the choice of colours in charts like this one but I think the Google version looks fine.

Quarterly change in average London house prices - comparison of indices

Most of the report consists of fairly standard presentations of market data. But one thing I would like to draw people’s attention to is the presentation of changes in average rents as published by the Valuation Office Agency. We show these changes at Inner London, Outer London and London-wide level to show that the London figure can be significantly distorted by shifts in the VOA dataset, notably the exclusion of a large number of Housing Benefit cases in Outer London over the last year which has skewed the balance of the dataset towards Inner London. So the average rent for a one bedroom property in London seems to have risen 13% even though the average in Inner London rose by 8% and the average in Outer London by ‘only’ 6%! I’m not sure these features of the VOA dataset are widely understood but lots of people are using their data to calculate changes anyway.

Change in median private rents in London, March 2012 to March 2013

Net housing supply by hexagon

This map, which didn’t quite make it into Housing in London 2012, shows total net conventional housing completions between 2007/08 and 2010/11 in London, aggregated using an artificial hexagonal grid in Quantum GIS. This type of grid can be useful for aggregating point data, though it still suffers from the usual problems of shaded maps in that variation within the classes is lost.

Net conventional housing supply in London, 2007/08 to 2010/11

The data comes from the London Development Database maintained by the GLA and comprising data provided by the London boroughs. My colleagues in the GLA GIS team have made an excellent interactive map for exploring LDD data, which you can find here.

The colour of London’s commute

This map shows the broad mix of transport modes Londoners use to get to work, according to the 2011 Census. It uses RGB space to show the share of car/van/taxi/motorbike (in red), cycling/walking (in green) and public transport (in blue).



A couple of notes / caveats: it is based on place of residence rather than place of work, so the central area is green rather than blue because city centre residents tend to walk while city centre workers tend to get public transport. And it shows the main mode of transport so will tend to exclude short journey stages such as walking to or from public transport.

The map was made in R, and was inspired by James Cheshire’s maps of voting patterns.

Housing in London 2012

One of my main tasks each year at the Greater London Authority is to publish ‘Housing in London’, the evidence base document for the Mayor’s London Housing Strategy. It summarises key facts and trends across a range of housing-related topics, with an emphasis on visuals. The 2012 edition was published online just before Christmas and is available here (warning, it’s an 11mb PDF).

I plan to publish a few of the charts from Housing in London 2012 on this blog. Below is the very first chart in the document, taking a 110-year view of trends in population, households and average household size in London based on Census data.

London’s population grew rapidly in the last decade, reaching 8.2m in 2011 and fast approaching its previous peak recorded in the 1939 Census. The number of households also grew but not so quickly, with the result that average household size increased for the first time in at least a century. This is likely due in part to housing supply not keeping up with demand.

Trends in London's population, number of households and average household size, 1901 to 2011