Where Area Equals People

What would the world look like if countries were resized according to the number of people living in them? You can explore that question in Gapmover, an map that shows how the relative size of countries has changed from 1800 and is projected to change through to 2100.

Unlike a conventional map, this animated population cartogram continually distorts the shapes and sizes of countries so that their area reflects their share of the world's population. As you drag through the timeline, countries swell and shrink, offering a striking visualisation of the changing balance of population around the globe.

The effect can be quite surprising. China, for example, is the world's most populous country for much of the animation, yet its relative size actually declines throughout the entire period as the global population grows. India follows a different trajectory, becoming relatively smallest around 1980 before its population growth eventually sees it overtake China around 2020.

One of the biggest transformations involves Africa. While many parts of the world shrink in relative terms, Africa expands rapidly during the 21st century, with Nigeria projected to overtake the United States in population by around 2060.

Gapmover is more than just an animated map, however. Its developer has created an algorithm specifically designed to resize countries while attempting to preserve their recognizable shapes and relationships with their neighbours. Shared borders are maintained, while additional "bridges" prevent islands and nearby countries from drifting away from their geographical positions. The result is a cartogram that can dramatically change the apparent size of countries based on different metrics, without completely losing the familiar shape of the world.

You can also see this algorithm at work on World Sizer - a map that resizes countries based on population, GDP, emissions and other measurements.