London Squared

The City Intelligence Unit at the London Datastore has released a really interesting visualization of London Commuting Flows. The visualization uses an interactive cartogram to show where the residents in each London borough travel to work within London.

The cartogram repesents every London borough as a small square. Each of these small squares is a mini choropleth map showing where in London the local residents commute to work. In other words the visualization consists of small multiple maps organized geographically. You can actually mouse-over the smallest borough squares within each individual borough square to view the number of commuters who commute between the two boroughs (which makes the cartogram sound a lot more complicated to use than it really is).

I like this visualization a lot. As a static image it would be an effective visualization on its own of the spatial pattern of commuting in London (the majority of commuters from each borough tend to work in central London or in neighboring boroughs). As an interactive visualization, however, it allows you to drill down and explore the commuting flows of individual boroughs and view how many residents from each borough travel to every other borough in the capital.

The  London Commuting Flows visualization was created using After the Flood's London Squared D3 module. This module allows you to easily create your own similar looking interactive cartograms of London.