Seasonality of the Slave Trade Voyages, 1751-1795

A temporal analysis in ArcMap of the slaving voyages in the database yields the following temporal vizualization. Forty-six of the forty-eight voyages are Dutch and two British, most of them transporting enslaved people across the Atlantic from Africa to Suriname and the Caribbean. Forty-four of the voyages also appear in the Trans-Atlantic Slave Trade Database. For further details on the voyages, see this post.

I achieved the visualization by changing the year of each voyage to a single year, setting both the time interval and time window to one week, and creating a new point feature in the South Atlantic labeled with the month field. The daily-position symbols are triangles, with a week’s worth showing at a time. Their colors represent the direction of the voyage segment, based on their destination fields: green for northbound, orange for southbound, and purple for westbound. That compresses the voyages, which took place from 1751 through 1795, into a single annual period and allows analysis of variation by week and month.

The Trans-Atlantic Slave Trade Database contains many more voyages than this GIS and therefore reveals a great deal of variation in seasonal patterns and why it occurred, as explained in this essay.