Submitted by Frank, who says:

Hello, months ago I designed a curvilinear version of Barcelona’s railways and proximities. I think it’s interesting because it gives a new vision of the lines, and also I tried to make it satisfying to watch. I’d like to receive professional opinions of my works, so I send it in this interesting website.

Transit Maps says:

This is a really interesting design experiment, and Frank has executed it expertly – the curves are nice and smooth throughout with some lovely transitions. The right hand side of the diagram does become noticeably busier than the left because of the proliferation of Metro lines and stations there, though I imagine that it would take some serious reworking to expand that part out more. Curvilinear diagrams are pretty unforgiving if adjustments are needed – it’s not just a matter of moving a line or two over a bit like on a “traditional” rectilinear diagram, but instead completely redrawing the arc – or arcs! – that are affected.

The main problem I have with this diagram – as lovely as it is – is that it just doesn’t match my mental picture of Barcelona, one of the most famously gridded cities in the world. The coastline and surrounding rivers give some geographical cues, but I wonder if some more might come in handy – areas of green parkland at Montjuic and Parc Guell, for example. Without the straightness of Barcelona’s grand avenues to provide context, the curvaceous rail lines just seem to meander from station to station, often taking a fairly circuitous route to get there. Some people think curvilinear route lines are easier for the eye to follow, but it’s definitely a balancing act to usefully convey information while still looking aesthetically pleasing.

Our final word: Definitely interesting and quite graceful, though I still have my doubts about the overall utility of curvilinear diagrams like this.