A century of ocean shipping animated
Apr 12, 2012 12:20 am • Permalink Using hand-recorded shipping data from the Climatological Database for the World's Oceans, history graduate student Ben Schmidt mapped a century of ocean shipping, between 1750 and 1850. The above map animates a seasonal aggregate.
There aren't many truly seasonal events, but a few stand out. There are regular summer voyages from Scotland to Hudson's Bay, and from Holland up towards Spitsbergen, for example: both these appear as huge convoys moving in sync. (What were those about?) Trips around Cape Horn, on the other hand, are extremely rare in July and August. More interestingly, the winds in the Arabian sea seem to shift directions in November or so. I also really like the way this one brings across the conveyor belt nature of trade with the East.
The bobbing month label is distracting, but its position actually does mean something. Since seasonality (i.e. weather) plays a role in travels, the label represents noontime location of the sun in Africa. Okay, I'm still not sure if that's actually useful.
If you really must, you can also watch the century of individual shipments during a 12-minute video.
By the way, Schmidt used R to make this, relying heavily on the mapproj and ggplot2 packages. (Bet you didn't see that coming.) I think he created a bunch of images and then strung them together to make the animation.
[via Revolutions]
Too many axes
Apr 11, 2012 10:18 am • Permalink Kaiser Fung talks about the suck of overlaying plots to show a relationship.
When the designer places two series on the same chart, he or she is implicitly saying: there is an interesting relationship between these two data sets.
But this is not always the case. Two data sets may have little to do with each other. This is especially true if each data set shows high variability over time as in here.
This seems to happen a lot when people take the data-to-ink ratio too literally or they're trying too hard to be clever within a given space. Overlays work on occasion, but I can't think of any that did off the top of my head. Most of the time it's better to split up the layers into multiple charts.
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