Saturday, 25 March 2017

Iron Viz - We can't breathe

It’s that time again with IronViz feeder competitions starting up again. Every year, I take this opportunity to explore a technique I haven’t used before, or alternatively, a subject that I care about.

As a keen cyclist in London, Air Quality is a really important subject to me. With increased cycling infrastructure, the move to electronic cars and banning older vehicles from the city centre, I was expecting to download a set of data that showed dramatic falls in the levels of pollutants that are all around us Londoners. Nothing could be further from the truth.

Using data from, I looked at the Borough level of detail as there are only three or four monitoring points per Borough. The data proved a challenge with sporadic measurement across an inconstant set of pollutants. This meant that finding trends and understanding geographical patterns using the new Spatial file connector in Tableau was a good challenge.

The biggest break-through I had was whilst researching the subject, was coming across the European legal limits that have come in to force across different pollutants, at various points since 2005. This is shown as the reference line on the trend data to show how often the limits are broken across London.

The answer in many cases is the daily average often doesn’t fall below some of the limits. Worrying stuff!

The spatial mapping allows the reader to see the impact on the city centre. Although Lambeth, outside of the true centre of the City, seems to be hit particularly hard by pollution levels.

As with any IronViz entry, it’s a chance to use a little imagination and have some fun with charting. When I played with some charts, it looked like exhaust fumes so, I kept it and features it at the top of my visualisation.

Overall, the visualisation has led me to want to dig in further in to this subject and what I can do to start making a difference as currently there isn’t any improvement of any note.


  1. Thanks for sharing valuable information. Your blogs were helpful to tableau learners. I
    request to update the blog through step-by-step. Also, find the tableau news at
    Tableau Online Training Blog.

  2. The Original Forex Trading System: roboforex login Is The Original Forex Trading System. It Is 100% Automated And Provides An Easy-to-follow Trading System. You Get Access To Real-time Signals, Proven Methods, And A Money-back Guarantee.