A Divided Libya Struggles Against Islamic State Attacks [Source]
In a recent Wall Street Journal piece about Libya, oil, and the Islamic state, there are two interesting data visualizations. They are both related to the same story, but I will address their merits individually. The first chart, Hot Spots, is very strong. However the story’s second chart is less than ideal.
The first visualization is of recent Islamic State attacks in Libya. This is a very strong chart in many ways. In broad-strokes, it displays the data very clearly and in simply. It adds to the reader’s understanding of the story. And it is visually pleasing without being distracting.
More specifically, the author has chosen the obvious way to show a set of locations: a 2D map. Each data point on the map, with is an attack site, is symbolically represented with a black dot surrounded by a red explosion-looking icon. The black dot shows the exact point of the site, while the red icon draws the eye towards the data.
The scale of the map is sufficient in allowing a reader to clearly distinguish the various data points. The light texture on the map’s surface gives some auxiliary information about the geographic terrain, but it does not distract or complicate things.
Since, on a global scale, the data points are relatively close together, the map is fairly zoomed in to northern Libya. However, the mini-map in the bottom left corner of the screen gives the reader context to what part of the region (northern Africa), the up-close map is focused on.
Libyan Oil Squeeze
The second chart, which attempts to convey Libya’s hurting oil production and revenue, is much weaker.
oth data sets being displayed in this chart (Oil production and petroleum revenue) are quantities over time. In the left chart, time is (properly) plotted on the horizontal axis. However, in the right chart, time is plotted vertically, which adds confusion and makes it very difficult to quickly scan for trends over time.
I hypothesize that the author knew this chart was weak and did not convey a message alone, so the subtitle of the chart is a straightforward, plain text explanation of what the chart is actually trying to convey.