Sizing up by squares

These three diagrams from a 1916 book about the British Empire show an early use of cartograms to represent the population of the world. Cartograms are maps that distort territorial size in order to show the magnitude of some other distribution.

In the first of these maps, the population for each country is represented by a rectangular area scaled to the total population. This method is used to avoid one of the major limitations of choropleth maps, which is that places that cover large geographic areas appear important, even if they aren’t actually heavily weighted in a data set that is being shown. For example, in this map, when Canada is drawn as a proportion of its population, it takes up far less room than on a map that preserves geographic area. Conversely, the United Kingdom appears much larger than it would otherwise, since it is physically small but densely populated.

Maps like these can be difficult to read, however, because they destroy the shapes which help us locate places on a map. While cartograms typically try to preserve geographic relationships (Canada is still north of the United States, for instance), at some point it becomes impossible to maintain every territory's relationship with its neighbors. The second diagram in this series shows cartograms overlaid on top of a Mercator projection. This technique makes it easier to identify familiar places—and, in this diagram, the cartographer has also added a dotted rectangle for each country to offer a comparison of its land area.

The last graphic of this series is no longer a map, but rather a data visualization that compares the population of countries across the globe. The color red is used across all three diagrams to show Great Britain and its imperial subject, following the tradition of using red to signify Britain's imperial extent. This figure also makes an argument about population classification which showed how racial and imperial logics intertwined. In the British Empire, Canada and Australia are counted fully towards the population, given their predominantly white populations by this time. New Zealand has a small inset for its Native population, while a large fraction of South Africa is shaded out for its Black population. India and several of Britain's other predominantly nonwhite colonial possessions are shown with hatchmarks, a visual symbol that's also used to distinguish the colonial populations of Germany and France. And, finally, the “Negro Population” of the United States is broken out into a separate category. From the point of view of the people who created this data visualization, nonwhite populations did not fully “count” towards an empire's self-accounting.

While the intent of cartograms can be to more accurately show data and statistics, these particular maps were used as tools by the British Empire to imply that the Chinese Empire was of relatively less global importance. The author notes that, “The people of China are one race inhabiting one country […] In the British Empire, on the other hand, are comprised people of every gradation in the human scale.”