This calculation is the reason we don’t need one of those long, complex formulas shown earlier to create the correct number of axes. These points are specified by their distance (r) from a reference point (the centre), and their angle from a reference direction (θ).Ĭalculation 1: This deciphers the angle (θ) of your radar chart, therefore, allowing us to create the number of axes we need for each of the dimensions we wish to plot. Polar coordinates specify points differently. This is the “normal” format you most often come across, in which points are specified using numerical coordinates across perpendicular lines (x,y). Accordingly we have to covert the typical “Cartesian co-ordinates” Tableau utilises (a.), into the polar coordinates required for a radar chart. Radar charts are circular, however, Tableau doesn’t really think in circles, as the notion of “polar co-ordinates (b.)” isn’t something innate within Tableau. The MethodĪ quick explanation of why a radar chart is a little tricky. The implication of this is that this method is pretty complex and less robust than the one I detail below, as it requires long formulas which hard code the number of dimensions. The alternative is simpler and more robust, and requires only 4 short calculations which don’t have to be tailored to the number of dimensions you intend to visualise, meaning you don’t require an understanding of trigonometry and you are able to filter dimensions from the view and your chart will automatically update. Thus, the formula you use will differ between a 5, 8 or 10 axis chart. In addition, within these calculations, the values need to be calculated within accordance worth how many “legs” you want your chart to have. I really like this view, apart from the range of average scores given when all sports are in the view – which I’ll need to work out how to fix.Īfter scouring YouTube videos and some blogs, I could only find very long and confusing calculations, in which something like this would be required for the X axis alone: I was anticipating this being pretty difficult, however, this took me very little time to create once I stumbled upon some good solutions. Nonetheless, I’ve seen a few on Twitter lately, and they reminded me of an old Makeover Monday in which ESPN rated 60 sports across 10 different categories, and I thought this would be a really good use case. However, they can also make comparison a little difficult this blog by Graham Odds details why radar charts aren’t always the best choice. Radar (or spider) charts can be an effective way to show certain types of data.
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