The featured image is an example of first-rate data visualization. It depicts the totality of the trans-Atlantic slave trade, with a column for the number of people who embarked in a given year, and a column for the number of people who disembarked. Not only is it clear and easy to read, but the use of a lighter color to denote “embarked” vs. a darker color for “disembarked” means that the difference — those who died during the Middle Passage — looks ghostly.
The graph is part of an interactive timeline from the Trans-Atlantic Slave Trade Database. The database is an incredible compendium of information from shipping manifests, logs, and so on for over 27,000 voyages.
Learn more about the trans-Atlantic slave trade in WorldView Software’s World History A, particularly Chapter 20: The Age of New World Exploration, and Internet Project: Triangular Trade.
Preview WorldView Software’s programs for free at http://www.worldviewsoftware.com/preview/