Olivier Beauchesne (Science-Metrix) publishes a map of scientific collaboration
Used data from scientific journal aggregators like Elsevier’s Scopus and Thomson Reuter’s Web of Science
Scientific collaboration between scientists in cities were geocoded and used the Great Circle algorithm to trace the lines of collaboration between cities
The brightness of the lines is a function of the logarithm of the number of collaborations between a pair of cities and the logarithm of the distance between those same two cities