Other Results

The below three Web maps provide an analysis of the patterns of death among the enslaved and disposal of their corpses overboard during the Middle Passage from Africa to the Americas. The first uses proportional point symbols to convey the number of deaths on a particular day at a particular position in the Atlantic. The second displays the density per 10,000 square kilometers of deaths and disposals on all the voyages with such data. The third compares the two first Web maps using a slider. They all provide innovative visualizations of one heinous aspect of the Atlantic slave trade, allowing users to appreciate more fully the suffering that took place on those infamous voyages. (Note that the time function is not implemented in these three Web maps.

A temporal analysis in ArcGIS of the slaving voyages in the database yields the following video vizualization 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 mean 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, but on the basis of departures and arrivals from ports rather than analysis of the oceanic voyages themselves.