Saturday, January 12, 2019

Animated Population Cartograms

In December Engaging Data created an interesting animated map to show the 'true size' of countries around the world. The Real Country Sizes Shown on Mercator Projection map allows you to switch between countries as they appear using the Mercator projection and their 'true size'.

Engaging Data has now created a similar map which scales each U.S. state by the size of its population. Press the 'Click to Show Population Size' button on the Scaling the Physical Size of States to Reflect Population map and each state on the maps shrinks to effectively create a cartogram of the United States where the size of each state relates to their relative populations. Each of the states are also colored to reflect the size of the state's population. The result is therefore a choropleth cartogram. Just click on the 'Click to Show Physical Size' button to switch back to the choropleth map view.

If you click on a state on the map you can view the state's actual population. You can also view how much the new size of the state is as a percentage of the state's original size on the map. This figure gives you an indication of how densely or sparsely populated a state is. For example, the re-scaled Alaska is just 0.1% of its original size. This is because the state is very large and has a relatively small population. New Jersey on the other hand remains the same size (100% of its original size), reflecting that it is America's most densely populated state.

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