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    Re: Accidental map of the doldrums
    From: Frank Reed
    Date: 2014 Jan 3, 18:08 -0800

    If you hit the links in that blog article leading back to the source and the sources for that source, you'll find that things are not quite what they seem. The author in the first blog (linked) marvels that the "centre of gravity for global maritime commerce clearly is the east coast of North America" (with a footnote indicating that he realized later that this was a mistake). This is the late 18th and 19th centuries. Obviously that's not global commerce. The database is for American shipping. It's still filled with interesting statistical information and an underlying story of trade and commerce. There does indeed appear to be evidence of the doldrums along the equator, however that's not the origin of some of the other "stripes" in the Pacific. Anyone who's attended one of my presentations where I've discussed 19th century whaling voyages has probably seen a similar map with a great concentration of points in a "stripe" west of the Galapagos. That's the whaling grounds. Whaling vessels cruised back and forth for months on the grounds. Similarly there is a concentration of points in the Gulf of Alaska. Those were summer (northern hemisphere) whaling grounds.

    There's an interesting navigation problem in plots like these. If longitude is uncertain, what do you plot? After 1840 or so, the uncertainty is significantly reduced. But what do we do in earlier decades?

    -FER

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