Flow maps

http://www.slavevoyages.org/tast/assessment/intro-maps.faces
Flow maps are a sort of mix of maps and flow charts. These maps effectively show movement of something from one place to another. This could represent immigration, trade, or a mixture of the two: the slave trade. The flow chart pictured above is the same flow chart in many history books describing the atlantic slave trade, the arrows represent exactly where the slaves were shipped to and from.