This is the continuation of a blog post I published a few weeks ago on how to draw directed arrows in Tableau. The approach introduced there – I dubbed it the “linear” approach, as instead of drawing one line we created two additional lines for the arrowheads – works fine on scatterplots, but things turn out to be a bit more difficult when working with maps. This article shows how these difficulties can be overcome using some on-the-fly reprojection of our data. While I claim the arrows to be my original idea (at least I didn’t find anything similar on the web – please correct me if I’m wrong!), I can’t and won’t take credit for this one. All original work was done by Alan Eldridge and the @mapsOverlord herself, Tableau’s Sarah Battersby in an article on hexbinning on Alan’s blog back in 2015. Sarah is an absolute expert on all things map projection, as she has shown time and time again in articles on the topic on the official Tableau and Tableau Public blogs and elsewhere (as in: real scientific publications).
In a recent blog post I showed how easy it is to create maps in Tableau showing paths, basically lines connecting two points each: the start and end locations. Those can be departure and arrival airports of certain flight routes, origin and destination of refugee flows, source and sink of money transfers, … the possibilities are endless!
But now imagine a map with a line connecting two locations A and B. Or rather many such lines. What information does this hold for you? What insights can you get out of such a viz? There is one very important element still missing! That is: which direction is this connection? Sure, there are cases where direction doesn’t matter, but thinking of the three aforementioned example use cases, many times it does! So let’s give our connecting paths some directionality. Let’s take simple lines and make them arrows!
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.
A number of colleagues, customers, people visiting any of my public presentations and even friends have asked in the recent past about my Windows desktop wallpaper and where to get it.
The first question I get most of the time is: “Is it real?” Well, no. Unfortunately it’s not. I’d love to have enough time to build something that awesome in real LEGO bricks, though!
So, if it’s not real, then how was it done? As is often the case with me I got the inspiration from one of the many blogs I read on a regular basis. In this case it was an article by John Nelson over on his blog Adventures in Mapping. There he showed an easy-to-follow way to LEGO-ify maps and satellite images. And I did exactly the same, just with an image of the lovely Tableau logo (Tableaugo? … maybe not) after scaling it to a Full HD resolution of 1920 x 1080 pixels and filling the empty space with white
bricks pixels. Credit where credit is due, so I won’t nastily copy & paste the how-to here but instead redirect you to John’s writings. In the meantime John and Vanni Zhang, another map and LEGO geek, even whipped up an interactive website that allows you to automagically generate LEGO-ified maps from web maps.
Give it a try, enjoy the LEGO style and take care not to break any virtual fingernails with those pesky 1×1 bricks… Also, show us what LEGO-goodness you came up with! Oh, and feel free to download my TabLEGau wallpaper. When sharing I’d be happy if you told people where you got it from.