Distortions of the Tube map visualised

Generalisation…

The London Tube map is known for its iconic design. However, as most later public transport maps adhering to some or all of Harry Beck’s original design principles, the Tube Map features marked spatial distortions. They are introduced through the adopted simplification or schematisation which, for example, strives to orient public transport lines in increments of 45° of azimuth, as seen in below snip of the map.

London Tube map with grid representation of the inherent distortions. Image by Spiregrain (http://www.ksglp.org.uk/map)

A while back, I blogged about The Real Underground which – for a small area – morphs the 1933 Harry Beck design of the Tube map into the current one as well as into a geographically accurate representation. I also blogged about the recently devised Noad map of the Tube which – while retaining a schematised and clean appearance – aims for a geographically more accurate representation than the original and the current design.

A person nicknamed Spiregrain has come up with yet another take at the Tube map’s distortions: Spiregrain added a geographical grid (including the distortions) to the original Tube map. The result can be seen above and in bigger detail on this website.

… and its effects

The distortions in public transport maps potentially have consequences for users. There are developmental theories by Siegel and White (partly also attributed to Piaget) which posit that spatial knowledge is acquired, first, through the acquisition of landmark knowledge, then route knowledge and, finally, survey knowledge.

(The strict sequence of these steps as well as the existence of the steps in itself has been challenged by others. I don’t want to discuss the merits or failures of this theory, specifically, but rather use it as a simple image that might help to point to some of the strategies people can adopt for navigating and/or building spatial knowledge.)

Imagine yourself in a new city. I’d suggest that a fair share of people start out orienting themselves relatively to some salient landmarks (if present and handy). For example, I happen to have talked to several people recently who, independently from each other, told me how they navigate in and around Paris: always glancing for the salient (and – very handy – well visible) Eiffel tower for judging their location, movement direction or distance to some point. In other situations, people try to memorise paths. Sometimes they do so for the simple purpose of finding back to their hotel, tent or that great restaurant of yesterday evening. For some people the real gain in spatial knowledge happens, however, when they start laying different paths through a city and when the paths merge and cross each other (if people realise that they do). In that last situation a person can build an overview of a city’s layout, a mental map which encapsulates what Siegel and White called survey knowledge.

However, imagine the acquisition of path knowledge is carried out not by trodding down streets but by using the subterranean public transport system. And the pre-trip planning of the route (as well as potential en-route re-planning) is done using a schematised public transport map. It seems indeed possible that people who “learn” a city that way, introduce considerable distortions into their mental maps:

When I first came to live in London I used the tube to get everywhere, but after about 6 months or so I started to walk –  being a country boy originally I was used to walking 5 to 6 miles without giving it a second thought – and I was really surprised how distorted the sense you got from the tube map was. So then I started to walk everywhere to both save time and get a sense of the overground.

That is the voice of a commenter on BoingBoing on how he acquired distortions into his mental map and how he made his mental map geographically more accurate by re-adjusting some relations between locations on his map on walks.

There are hints that the fashionable, strongly schematised public transport maps we all have come to know, rely on and potentially like, introduce bias into our mental maps. However, how to find an adequate (easy to use and pleasantly looking) fix to the ubiquitous design of transport maps seems like a difficult question to me. Spiregrain’s is certainly not the last proposal we’ll see in this domain, but it makes for an interesting starting point.

(via BoingBoing)

Ralph Straumann

Ralph is a world-citizen, a geoinformation specialist by profession, and interested in many topics. Here, he'll confine himself mostly to things geo-visual.

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