Flow Maps

Flow Maps

Texas Freight Flow Map

http://www.lib.utexas.edu/maps/texas.html 

Flow maps are used to show the movement of objects from location to location, for example in Texas the total combined truck flows, flight paths, the amount of goods being traded etc.  There is an advantage of flow maps that being they reduce visual clutter by merging edges. Again colors are used and the more the network flow increases the lines become thicker.