Flow Map

A flow map is a type of map that shows the movement of something from one place to another. These maps are used on a day-to-day basis to exhibit many different types of information. For example, many airlines use a flow map to show the different locations to which their company flies. The more lines pointing to a location, the more flights that location receives. Flow maps can basically be used to depict anything that moves from one location to another. The picture above is an example of a flow map that displays traffic. The lines near the big cities become darker showing the increased traffic in those areas.

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