Flow Maps

Flow maps have been used for centuries to show the movement of objects or people from one location to another. They illustrate the flow of people in and out of countries (migration), import and export of goods and raw materials, as well as the flow of wealth across nations.

One example of the use of flow maps would be the illustration of the slave trade, and the movement of slaves from Europe to Africa to the Americas and Carribean, as shown below:

http://exploringafrica.matrix.msu.edu/images/slave_routes.jpg