I saw some historians talking on Twitter about a very nice data visualization of shipping routes in the 18th and 19th centuries on
Spatial Analysis. (Which is a great blog--looking through their archives, I think I've seen every previous post linked from somewhere else before).
They make a basically static visualization. I wanted to see the ships in motion. Plus, Dael Norwood made some guesses about the increasing prominence of Pacific trade in the period that I would like to see confirmed. That got me interested with the ship data that they use, which consists of detailed logbooks that have been digitized for climatological purposes. On the more technical side, I have been fiddling a bit lately with ffmpeg and ggplot (two completely unrelated systems, despite what the names imply) to make animated visualizations, and wanted to put one up. And it's an interesting case; historical data was digitized for climatological purposes, which means visualization is going to be on of the easiest ways to think about whether it might be usable for historical demonstration or analysis, as well.
So here are two visualizations.
[Update 11/12:
For more of this, see my discussion of American shipping, and whaling in particular, from 1800 to 1860.]
The first one is long: it shows about 100 years of ship paths in the seas, as recorded in hundreds of ship's log books, by hand, one or several times a day. I haven't watched the whole thing at once, but skipping around gives a pretty good idea of the state of the database (if not world shipping) at any given moment.
You can watch either of these in much higher resolution by clicking around here or on YouTube--I definitely recommend 720p.
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.
The second has to do with seasonality: it compresses all those years onto a single span of January-December, to reveal seasonal patterns. I loop through a couple times so you can get a better sense, but the data is the same for each year.