Flow Map

 

http://mappa.mundi.net/maps/maps_014/

Cartographers use flow maps to show the movement of objects from one location to another, such as the number of people migrating, the amount of goods being traded, or the number of packets in a network. Flow maps reduce visual clutter by merging edges. This map is a telecommunications traffic flow map of the European region. It shows countries with traffic flows between them represented by smoothly curved red lines. The thickness of the lines is proportional to the annual volume of traffic between those two countries, measured in millions of minutes of voice telecommunication. This map shows that the UK, Germany, and France dominate traffic intra-European flows.