On Sunday 7th July, five teams are attempting to ride London public bicycle hire bikes between all 800 docking stations, docking and retrieving a bike at each one. That’s over 360km of riding in total over an area of over 120km².
I’ve created a live tracker (active during the challenge day, 7th July) with Observable here:
It updates with a couple of live feeds: one from Transport for London that carries live info on the status of each docking station; the other from the challenge participants that use a mobile app to log docking station visits.
There have been some technical and design challenges in producing the mapping, including automatic cleaning of inconsistently coded data from the live feeds, and perhaps more interestingly, the representation of point based locations (docking stations) in a way that conveys ‘progress’ in covering London.
I opted to use Voronoi regions around each docking station to give a continuous areal coverage (coloured by the team that gets to the docking station in the region). While these are easy to calculate for a set of planar embedded points, the challenge is to make their boundaries geographically relevant, especially around the river Thames and the outer boundary of the the region. For the former I effectively created a modified Delaunay triangulation following the river centreline. This keeps regions north and south of the river distinct. For the outer boundary, I used alpha shapes with dilation, as detailed here.