The visualisation of flows has been approached in many different ways through the history of cartography and mapping with early examples such as the British Coal export Map by Charles Minard. For this post I will be looking at the flow of London Barclay’s bike hire scheme. The first visualisation as displayed below uses a combination of base map and individual markers for each bike displayed through time.
This first visualisation allows the user to reference the location of individual bikes however, an error within the processing code resulted in all bikes going to incorrect destinations. Having solved this problem, the next sketch removes the basemap to provide a less congested visualisation. The white points indicate bike journeys and the red flashes indicate the start of a journey.
This visualisation is an improvement on the first but the mix of colours does not work as well as it could. This is addressed in the final visualisation below where the trip beginnings flash white. Though simple the effect through the video is to see the concentration of starts moving from the outside zones into the centre and about 5pm the reverse with many trips initiating in the city of London region.
The final product works well and indicates and shows the movement of bikes through the day. Problems with the visualisation however are the lack of a spatial reference to orientate the user and also an indicator of the total number of bikes in use at any time.