"History of United States Congress - xkcd"
The comic artist xkcd creates and features different graphs and data visualizations among his regular comics. They tend to cover some very interesting topics in fairly unique ways like his visualizations of character distance in popular films and his maps of the internet which I might talk about in another week. But for this week, I wanted to talk about this older map I found displaying the partisan/ideological makeup of congress. Following each presidential term in the center timeline, both the senate and house are composed of a circulatory system like scale measuring the number of left or right-leaning members and how far to those perspective sides they're leaning. It is a very large and beautifully unique looking chart at first glance. Its coloring is intuitive using varying shades of blue and red respectively. Many important dates and events are also highlighted right on the chart to help explain any shifts and trends. The main reason I wanted to talk about this visualization was, however, because of how hard I found it to read effectively. Even though it has two legends and each aspect of the data is meticulously explained, the actual way that the number of party members is displayed is distracting. The whole graph is based on the distance right or left in terms of the number of party members, but the branches split off to the right and left. These branches make it look like there are more members than there are. It's impressive to turn data that should be very ridged with most congress members leaving joining at the same time and turn it into this more organic shape, it's just a shame that it doesn't read as easily. The branches are also different sizes seemingly showing how many joined or left but the size of the branches don't seem to perfectly correlate with the resulting size of the colored blob. Though in actuality I suppose it's probably not important to know exactly how many congressmen left or joined down to the exact year and since this chart goes through the entirety of the American government this more general overview of party leaning is perfectly adequate.