Pedro M. Cruz, a graduate student in information visualization and interaction design, created this time-elapsed representation of the rise and decline of the British, French, Portuguese, and Spanish overseas empires from 1800 to 2000. He writes:
The data refers to the evolution of the top 4 maritime empires of the XIX and XX centuries by extent. I chose the maritime empires because of their more abrupt and obtuse evolution as the visual emphasis is on their decline. The first idea to represent a territory independence was a mitosis like split — it’s harder to implement than it looks. Each shape tends to retain an area that’s directly proportional to the extent of the occupied territory on a specific year. The datasource is mostly our beloved wikipedia. The split of a territory is often the result of an extent process and it had to be visualized on a specific year. So I chose to pick the dates where it was perceived a de facto independence (e.g. the most of independence declarations prior to the new state’s recognition). Dominions of an empire, were considered part of that empire and thus not independent.
via Hit & Run