Alan Penn

Lunch Hour Lectures at the University College London (UCL) are an opportunity for anyone to sample the exceptional research work currently being undertaken at the university. 18 January 2011 professor Alan Penn held a lecture titled ‘Who enjoys shopping in IKEA?’.  Penn explains how space is used to sell things, in particularly at IKEA’s. Parts of the analyses he uses to explain the habit of shopping can be used to analyse and explain pedestrian movement in an urban structure

Who enjoys shopping in IKEA?

Mean depth

At the start of the lecture (at 0:50) Penn clarifies how space  can be represent, so that we can analyse it. When the lines of an urban structure are represents as dots, and each one is connected to the lines that cross them, we’ll get a mathematician graph representing the street pattern. From each point you can lay out the pattern of urban space that provides insight in the connection of that point to the rest of the street pattern. The same urban structure will give an objectively different pattern (and sequences) from each point of view, with different distances. Each dot has it own mean depth to the other dots. Dots with a low mean depth are easier accessed from out the network,  than those with a high mean depth. Therefor, the dots with a low mean depth are the more used dots in the street pattern.

The mathematician graph provides insight in the order of the urban structure. The urban structure determines pedestrian movement. For a good urban square a low mean depth is essential.


Penn poses the intelligibility of an urban structure is essential  (at 21:30). If you don’t know where you are, how can you decide where you want to go to? This complements Voorhorsts Dutch book ‘Logische ruimte’ about how to make an urban design easy to use. Voorhorst introduces the term Claritas (unambiguity) as addition of Vitruvius‘ UtilitasVenustas and Firmitas




– A. Penn: “Who enjoys shopping in IKEA” [2011],



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