Alternative 3: Choropleth

A choropleth solves the cartogram's overplotting problem. However, it introduces a different problem. The choropleth below gives a very poor understanding of the distributions of GDPs, essentially splitting the world into three tiers: US, China, and others.

We can improve our ability to distinguish between the countries with smaller GDP by changing to a multi-color scale and transforming the data, as shown below. This does a much better job at allowing us to understand Africa. It also brings to the fore the poor state of the economies of central Asia, which is a feature not emphasized by any of the other visualizations.

However, this sharpening of discrimination among the smaller economies comes at a large cost. The naked eye struggles to discriminate between the bigger economies (e.g., Australia vs the US). Furthermore, just as the word cloud struggles when words differ in lengths, the choropleth has its own biases relating to the size of the countries. For example, Japan and Europe can easily be overlooked on this map.

Geographic visualization probably works the best for this particular data set. The next few visualizations are much more generally applicable, as they can be used for non-geographic data.

Alternative 4: The horn of plenty

The visualization below takes the bubbles from the cartogram and circle packing and orders them by size, which creates a surprisingly effective way visualizing the distribution of population sizes. However, once more the critical information about which country is which is hidden in tooltips, making this a poor visualization for most problems.

We can make the point that the US and China are the world's largest economies by adding labels. However, this is not such a compelling improvement. Most viewers could likely have guessed what these labels tell them anyway.

Alternative 5: Treemap

All the previous bubbles and plots showed size proportional to diameter, which provides a challenge to most quantitatively-oriented minds, and certainly introduces a degree of perceptual error. Treemaps are the rectangular cousin of bubble charts with circle packing, with the area of each rectangle proportional to GDP. Of the non-geographic visualizations, it is the best one so far, in that it both shows the distribution in a striking Escher-like way while allowing us to see the labels for most of the big countries. But, it is still not without problems. Some countries cannot be found. And, the relative ordering for all but the four largest economies is hard to discern.

Alternative 6: A donut chart (it does a surprisingly good job)

As I have mentioned before, the hatred that most numerate people have of pie charts is not justified. To my mind, the donut chart below outperforms all the non-geographic visualizations examined so far. Notably, it emphasizes aspects of the data not evident in any of the other visualizations. For example, it allows us to see that biggest four countries' GDP exceeds that of the rest of the world. If you are wanting to find data for one of the countries with a smaller GDP, you can, unfortunately, only do so via tooltips.