When waiting on the platform a minute on the London Underground often feels longer than you’d expect. I decided to investigate this, and get some clarity on the length of one tube minute.
To do this I had to start by gathering the required data.
Before I could record the duration of one minute according to the arrivals displays on the Underground, I needed to decide how I would measure this minute. Determining the start of the minute was easy. A minute starts when the arrival display switches to show that there is one minute remaining. The end of a minute was trickier to choose.
As far as I could tell there would be three options here:
– When the train enters the station
– When the train doors open
– When the train departs from the station
Because I wasn’t sure that I could always accurately record the point at which the train entered the station, and train departures can be delayed by people stuck in the tube doors, I chose to measure a minute as the time from when the arrivals display switches to one minute, and the time that the tube doors open.
With the method sorted I continued to record data using Reventer.
Having gathered the data I sent it to Google Docs (easy to do in Reventer) and started thinking about the best way to visualise this data. I’d recently read some good blogs about Processing.js, and having played with Processing in the past, I decided to use this to create the animation. I was also reading Nathan Yau’s Visualise This, which emphasizes using data to tell a story. To give readers the chance to experience the duration of the various tube minutes for themselves, I decided on using the animated balls to represent “minutes”.