100 years of ship paths in the seas :
This shows mostly Spanish, Dutch, and English routes--they are surprisingly constant over the period (although some empires drop in and out of the record), but the individual voyages are fun.
And there are some macro patterns--the move of British trade towards India, the effect of the American Revolution and the Napoleonic Wars, and so on.
I recently stumbled upon a fascinating dataset which contains digitised information from the log books of ships (mostly from Britain, France, Spain and The Netherlands) sailing between 1750 and 1850.
The creation of this dataset was completed as part of the Climatological Database for the World’s Oceans 1750-1850 (CLIWOC) project.
The routes are plotted from the lat/long positions derived from the ships’ logs.
I have played around with the original data a little to clean it up
(I removed routes where there was a gap of over 1000km between known points, and only mapped to the year 1800).
As you can see the British (above) and Spanish and Dutch (below) had very different trading priorities over this period.
What fascinates me most about these maps is the thousands (if not millions) of man hours required to create them.
A looped visualization of all the voyages in the Climatological database for the world's oceans as if they occurred in the same year, to show seasonal patterns in ship movements and predominant shipping lanes from 1750 to 1850.
Today we churn out digital spatial information all the time without thinking, but for each set of coordinates contained in these maps a ship and her crew had to sail there and someone had to work out a location without GPS or reliable charts.
Contrast that with this map of cargo ships (bigger than 10,000 gross tonnage) during ONLY 2007 :
Routes, ports and betweenness centralities in the GCSN.
(a) The trajectories of all cargo ships bigger than 10 000 GT during 2007.
The colour scale indicates the number of journeys along each route.
Ships are assumed to travel along the shortest (geodesic) paths on water.
(b) A map of the 50 ports of highest betweenness centrality and a ranked list of the 20 most central ports.