Taxonomy of Data Visualization Methods - Data Visualization: A Successful Design Process - page 151

Network connection map
Data variables : 2 x quantitative-interval, 1 x categorical-nominal.
Visual variables : Position, link, color-hue.
Description : Similar to the network diagram that we saw before, the intention of
a network connection map is to facilitate the exploration of complex geographical
connections. A connection map joins up related locations to form a pattern that
enables discovery of hubs, overlaps, clusters, and gaps—pretty much the same
focus as that of the network diagram but this time with the platform of geographical
coordinates. The exhaustiveness of certain datasets means an image of the atlas is
almost fully formed from the resulting patterns and there is no need for the actual
mapping layer to be visible. In the following image, we see the world's flight paths
with those involving Toronto highlighted in orange.
Image from "Toronto Flight Lines" ( http://www.biodiaspora.com/ ), created by Bio.Diaspora 2012