Everyone loves a good data visualisation, and they’ve never been more in-your-face than in the last couple of years. Whether mapping local language variations or the way the wind is blowing there's something new every day to whet your appetite for pretty data.
These visualisations are all driven by a widespread idea: that computers can do amazing things with data that could never be done by people using paper. Computers can make data move and pulse and zoom and scroll. Data on paper just sits there - immobile and boring.
But I don't think that zooming and swooshing are the most important thing that computers bring to data visualisation.
In fact, I think the most important advantage that computers have over paper is the ability to hide unnecessary information.
The rest of this post is my attempt to persuade you why this matters.
Why hiding information is so important
Let me explain by critiquing that most hallowed of all data visualisations: the Tube map. Here it is, in the current 2012 official printable form:
Over the last decade there have been dozens of riffs and variants* on this map: a new generation of design and data visualisation geeks tipping their hats to the genius of Harry Beck.
However, I think this reverence blinds us to something that should be staring everyone in the face: for an average user of the Tube the famous map contains approximately 100 irrelevent pieces of data for every one piece that actually matters to them. The data contained within the map is literally about 99% irrelevent to a user trying to get from A to B, especially for the 26 million tourists who allegedly visit the city every year.
This isn't Beck's fault. He did a world-changing job with the tools he had: paper, pens, typography and a brilliant design sense.
For 100 years this was the way things had to be. But then the web came along, and it suddenly became possible to show people information about their journey that was 70% or 90% relevent - not 1%. How? Through the data visualisation known as the Transport for London journey planner. Here's a sample journey:
Now I'm not going to defend TfL's web design here: obviously whoever designed it is no modern Beck. But my point is that the proportion of this screenshot which contains user-relevent information is hugely higher than can be contained on any map, even one designed by a legend.
This is because the computer makes it possible to conceal everything the user doesn't need to know: it takes the tiny sub-section of the Tube network relevent to this passenger and turns it into instructions, with the key part of the data visualisation being a scripted sentence. Data is visualised in the form of words, and a few icons.
This is a data visualisation that uses the capabilities of the technology to give the users what they need. It deserves greater respect than most sliding, zooming, pulsating online data visualisations you will see.
I want to see more data visualisions that make it clear that their authors have really thought about why the computers they have in front of them can help people more effectively than a quality paper design could. The paper Tube map is still more fundamentally useful than 99% of hot web visualisations, even though it was crafted on an infinitely more limited technology. Why aren't more visualisations simply better, given the power at our fingertips?
I think it comes down to the way that data visualisation gets increasingly framed as an art. I have no problem with people using computers to generate art, but I think that data visualisers are not best seen as artists: they are better seen as craftsmen building tools to help people to make their way through life. We should aspire to be Stradivarius, not Picasso.
* Whilst there are dozens of redesigns of the almost-perfect Beck map, there are virtually none of the obviously-flawed TfL journey planner. I think it is worth pondering why so many people want to tinker with the almost unimprovable paper visualisation, whilst ignoring the pressing design problem with a fundamentally more user-centric visualisation that gets 3m visits a month.