I had been planning to write this post for a long time. Not only have I been asked many times how to do this in my daily consulting work, but especially during and after my hands-on training “Stretching the Boundaries with Advanced Mapping” at our Tableau Conference On Tour 2017 in Berlin earlier this year. The question is pretty simple: How can I draw paths in Tableau? Oftentimes these are some kind of movement data, e.g. refugees or flight connections. The way to do this in Tableau is actually very easy – and some of the recently introduced features made it even easier – but it’s imperative to understand how Tableau draws lines and how the data therefore needs to be structured.
Have you ever received a spatial data set that you wanted to visualize in Tableau, only to find out the coordinates looked like this:
50°07'01.9"N 8°40'20.8"E If so, or if you’re just generally interested in geographic data and Tableau, this post is for you.
In 2013 Dr. James Cheshire from the Centre for Advanced Spatial Analysis at the University College London created a data visualization that was critically acclaimed back then and saw something of a renaissance a few weeks ago when a modified version by Henrik Lindberg made its way onto the Reddit front page. I had been mesmerized by the viz from the beginning, so when it reappeared in my blog reader I decided I had to try reproducing it in Tableau.
Imagine you have some kind of system that produces reports on your data – for this example I randomly decided to use bookings for events -, and these reports are published on a regular schedule. Now you want to see two things in your report:
- The current status of participants per event – both for past events (i.e. the actual number of participants) and for future events (i.e. the current number of people registered).
- An overview of how the number of people registered changed over time.
Also, your source system is publishing these data as
.csv files. How can this be done?
Well, very easily using the new wildcard union feature introduced in Tableau Desktop 10.1! Read on to see how this can be done.