Chapter 1 of The Functional Art by Alberto Cairo (Why Visualize: From Information to Wisdom) is a reminder that simple visualizations are useful, but they are not great when they are insufficient.
In the following graph created by Matt Ridley, we can see the insufficient graph which shows that there is a decline in world population (1950’s to 2005), but it really does not show much else.
In the next graph, we can see this visualization is a lot more informative, captivating, and detailed. It shows the average number of children per woman in a country, as well as the world’s average fertility rate. You may need to zoom a bit, but the message is clear and it is concise and interesting.
In Chapter 2 (Forms and Functions: Visualization as a Technology), I saw the following visualization which caught my attention (honestly, mostly because anything that has Venezuela in it catches my attention), but also because it is a successful visualization and it uses the correct tools.
Alberto Cairo writes that several variables have to be presented and that the visualization has to allow certain comparisons between other nations. Organization is also key when depicting these graphs, and there has to be relationships between the variables that are being shown.