The map above shows the routes flown by the top 7 airlines (by international passenger distance flown). The base map shows large urban areas and I have attempted to make it look a bit like the beautiful “Earth at Night” composite image produced by NASA. You can clearly see a relationship between where people live and where the big carriers fly to across Europe and the US but India and much of China have relatively few routes. I expect much of the slack is picked up by smaller airlines in these countries but they must represent key growth areas the world economy becomes increasingly driven by the east. This map isn’t meant to be comprehensive- I just wanted to make another example of a visualisation with ggplot2.
How I did it
Plotting great circles has become an increasingly popular thing to do with R (because they look cool) and the excellent flight path data freely available from the OpenFlights website provides a neat data source to play around with. There are several tutorials out there but none of them (to my knowledge) apply apply colour value to the arcs based on a relevant variable in the datafile or make much of the underlying base map. For the Tufte fans out there this is means an important opportunity for maximising data ink has been missed.