Category Archives: Domain-Specific

Visualizing Tennis

I’m a member of the American Statistical Association’s “Statistics in Sport” section (http://www.amstat.org/sections/sis/) and I’m also British by birth, so Andy Murray’s success at Wimbledon this year was interesting to me for two reasons. I took a look at some of the data on Murray (collected by IBM’s SlamTracker initiative — http://2013.usopen.org/en_US/slamtracker/ ) with a view to doing a little visual analysis, so now I have another reason to be interested …

I found some data on his performance over a few years leading up to Wimbledon 2013 and wanted to look at trends. Now usually I prefer to create several linked visualizations and look at them together, but for this data I found that several of the stats I was interested in worked nicely when plotted in the same system. Here’s what I came up with:

Image

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From the Vaults: Maps are Just Another Element

For the Grammar of Graphics language-based approach to visualization, and therefore in the RAVE visualization system, maps are simply another element that can be used within the grammatical formulation.

Although most people consider a map a very different entity from a bar chart, all that really differs between a bar chart and a map of areas like the one included here is that instead of representing a row of data by a bar, we use a polygon (or set of polygons) on a map. Otherwise their properties ought to be the same — we can apply color, patterns, labels, transparency. We can set a summary statistic when there are multiple values for each polygon to reflect min, max, mean, median, range, or any of the regular sets of items. We can flip, transpose and panel the charts. Essentially, from the grammatical point of view, if you can do it to a bar chart, you can do it to a map. The only limitation is that whereas the sizes of the bars can be set or determined by data, the map polygons cannot, so setting sizes on the map polygons has no effect.

US Chorlopleth

Orthogonality is also important — so we can say we want a point element instead of a polygon, as in the above where we’ve added a second element to a RAVE US Map conveying different data as well as being a good place to put labels