Rooting around the Web (you know, holding it upside down and shaking it to see what falls down) I found a set of classic examples of how to turn data around till it looks right. More specifically I was looking for data on how urban density affects gas usage.

First I found the following diagram in the Wikipedia article for “urban density“. It’s a classic example of “let’s plot points and see what happens”, and indeed it vindicates our intuition that density and petrol use are inversely correlated (click for bigger size):

Petrol use is inversely proportional to urban density

The comments on the talk page for this image are quite damming. The data for this diagram must be wrong; the mind boggles to find out that New York and Los Angeles have the same urban density, or that London is denser than Paris. Somehow the measurements are taking into account large empty areas within the administrative boundaries of cities.

However, dodgy data is not all that’s wrong about this diagram. It also misses an opportunity to explore the evidence, extracting qualitative features (cultural, even) from quantitative data. The discussion page offers this alternative diagram (again, you can click for bigger size):

Inverting density reveals different clusters

Plotting petrol consumption against the inverse of density (sq m/person instead of people/sq km) the data reveals that density is not the only factor in gas consumption. Australian cities are about as dense as US cities, but gas consumption in urban Australia is about half what it is in the US.

Other factors than density must be at play, and my hypothesis is that they could be economic, cultural, or both. This may be due to the lower price of gasoline in the US, and the fact that Australians tend to buy, on average, cars with a lower gas consumption. Petrol consumption in Australia remains almost flat over a 2x increase in inverse density, which suggests that maybe Australians have shorter commutes, or tend to roam a local area regardless of the size of their city.

In any case, this is an example of how pivoting the data reveals hitherto hidden variables.

[...] cities don’t exist just because people have had to be nearby to communicate; cities exist because people like to be near other people, and it is this fact, rather than the mere tradiing of information, that creates social capital.

Clay Shirky, Here Comes Everybody

The role of the collaborator is crucial in the Medialab-Prado workshops’ statement and development process, as the workshops are constituted as a horizontal collaborative work environment, knowledge interchange and theoretical-practical training among teachers, authors and collaborators.

You are invited to discuss the projects in the forums, and of course I will be glad to comment on Density Happens with anyone interested in collaborating. Preferred collaborators would fit one of the two following profiles:

Collaborator profile 1:

• has good grasp of maths
• is programming language agnostic
• feels at ease with declarative, functional and constraint-based programming styles, even in imperative languages
• is someone who will enjoy reading, implementing and extending these papers about cartograms.

Collaborator profile 2:

• has some experience with website scraping and data-munging, and/or…
• has some knowledge of Geographical Information Systems, especially map formats
• would enjoy extracting comma-separated files from this series of webpages.
• would enjoy merging the above into data extracted from this excess of Excel spreasheets.

Any question you have, please ask away, either here or at the Medialab-Prado Forum.

And please bear with me if I am still a bit vague: I am reading the relevant papers as fast as I can download them.

Peggy Noonan laughs at John Stewart's quip

You know what New York City is? A bunch of small cities, stacked together in one building!

John Stewart, The Daily Show, 2008-10-1

]]> http://madrid-melbourne.org/2008/10/john-stewart-explains-density/feed/ http://madrid-melbourne.org/2008/10/density-happens-selected-visualizar08-medialab-prado/ http://madrid-melbourne.org/2008/10/density-happens-selected-visualizar08-medialab-prado/#comments Wed, 15 Oct 2008 13:10:07 +0000 admin http://madrid-melbourne.org/?p=34 The list of projects selected for Visualizar08 has just been published, and I have also received an email telling me Density Happens has been selected. Thus I will be at the Medialab-Prado workspace in Madrid from November 3rd through the 19th. Thanks to the selection committee for their support and encouragement, and congratulations to the rest of the participants.

Madrid-Melbourne and one effect of urban density: it's night in Madrid, and there's people about; it's day in Melbourne, but there's not a soul in the street.

I have already filled in the characteristics of the Density Happens project at the Medialab-Prado forums, including the profile of preferred collaborators. As I have decided to focus the work of Density Happens on cartogram projection, I have gone for a very technical profile. Hopefully some of the would-be collaborators have a background in Computer Science with reasonable maths skills. If you fit the bill, and can be in Madrid during the first half of November, here’s where to apply for collaboration in Density Happens as a Visualizar08 project.

South Yarra, in the heart of Melbourne

I have found (similarly split in districts) demographic data for Madrid from 2001. The problem is Madrid, as all of Spain, has grown hugely in the past ten to five years. These data are woefully outdated now. And datasets through time would really help me too.

Density exhibit at the 2007 Venice Biennale. Photo by Ben Cerveny

Other projects have focused on density before, but I hope this one is the first that examines how everything else, from abortion rate to sales of icecream, from pollution to food prices, from teenage drunkenness to subjective measurements of happiness, can be related to urban density and its immediate effects.

It is also the case that Madrid and Melbourne are at the extremes of the spectrum of livable cities. There are bigger and denser cities, and also smaller and sparser ones. But Mexico City - Minneapolis or Moscow-Milwakee do not roll of the tongue as well, and, above all, do not surround the planet (although Mexico City is on a race with Tokyo to do it on its own).

So Madrid and Melbourne are here as a synechdoche for the two endpoints in my favourite segment of city livability. They define a line along which we can study all cities, reading into urban life through the datastreams each city produces. Think of madrid-melbourne.org as “information aesthetics meets City of Sound“. Or something.