Geohashing

Almost four years ago, I posted a comic laying out the Geohashing algorithm. The algorithm generated a set of random latitudes and longitudes each day, spread out across the globe so there was generally always one within a few dozen miles of every location. I figured they could be used for hiking destinations, sightseeing, meetups, or whatever else people came up with.

I wanted to make an algorithm that anyone could implement, which didn’t rely on a central authority or ongoing support from any one maintainer. I also wanted to make it impossible to know the locations more than a day or so in advance, so that if geohashing became popular in an area, no one could publish a list of future locations that woud give property owners, park rangers, or local police time to prepare. So each day’s coordinates are randomized using the most recent Dow Jones opening price, which isn’t known until the morning of that day—or, in the case of weekends, a day or two in advance, which helps with planning larger weekend trips.

In the days after I posted the comic, there was a flurry of geohashing activity, which quieted down as the initial novelty wore off. But it didn’t die, and for the past several years there’s been a small but vibrant community building around the Geohashing Wiki. There are numerous daily expeditions, and they’ve taken some beautiful pictures and come up with a lot of neat tools, games, and achievements.

One of the many things they did was use a tweaked version of the algorithm to come up with a globalhash, a single coordinate for the day somewhere on the planet (biased toward the areas near the poles). They’re usually over the ocean, but a few of the land ones have been reached.

Yesterday’s globalhash fell less than a kilometer from the South Pole. User Carl-Johan got in touch with the Scott-Amundsen research station, and later that day, the hash was reached by Katie Hess, Dale Mole, and Joselyn Fenstermacher of the US, Robert Schwarz of Germany, and Sven Lidström of Sweden.

Wow. Just wow. Congratulations.

If you want to look up today’s geohash for your location, you can use this online tool, or one of the others listed on the Coordinate Calculators page.

246 replies on “Geohashing”

  1. Just remember that while such alternative implementations can be fun and useful for arranging meet-ups, they don’t count as actual geohashes, and as that Israel page says, you cannot claim achievements for reaching these alternative points.

    Yes, in many graticules it’s hard to get a reachable point. But, that makes it all the more interesting when you finally get one. It’s a good reason to check the coordinates every day.

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  2. The world was made in 6 days, says the Bible, not 7. Then God thought of a day of chilling. Pretty clever for “some dumb 2000-year-old story.”

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  3. This is freaking awesome, thanks for sharing as always.

    @Reblevy Wrong site mate, this has nothing to do with that. Also, even a broken clock is right twice a day (or once, depending on make).

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  4. @ Justin Case

    That’s ridiculous. Polar bears live at the North Pole. Obviously it was a penguin.

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  5. I remember when this comic first went up, I thought it was awesome…its great to see it’s still going strong…

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  6. @Stuart Richards on March 3, 2012 at 10:54 pm said:
    There’s five guys mentioned but only four in the pic. What happened to the fifth guy?
    —-
    Obviously he’s taking the picture!

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  7. @MJZimmer88 said: Obviously he’s taking the picture!

    “Sorry I’m not in the picture mom. I went all the way to the South Pole and forgot to take the camera with the neat little timer thingy!”

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  8. Guys! We’re disturbing some sort of cosmic balance of the internet here. Someone has to use the word “fag”, “noob”, or incorrect grammar or else we aren’t technically “commenting on the internet.”

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  9. I may be mistaken on how big a 1 by 1 degree square is, but I wouldn’t imagine it would be very big. How often do you have to geohash for you to have basically visited your entire square?

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  10. Weird, you see 4 guys in the pic, but I think there’s one female, with the other one taking the pic?

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  11. This is a comment about your comics and not about your post.
    I usually ignore it when people refer to pickup in such terms, but i really like your comic and i was wondering if you really thought those things about pickup. Did you ever look into it?

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  12. off topic: why XKCD store does not sell black hats &/| berets (headwear analogous to that worn by recurring xkcd comic characters)?

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  13. The double entendre in the GeoHashing is that there is a group called Hashers that usually do a random meet-up every week/month to go for a 5k ‘stroll’ normally with some rough terrain (Shiggy). This could become a technical evolution sub-set of this group.

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  14. @Joe Sixpack, actually, a typical North American graticule is about 50 miles by 70 miles. That’s over 3600 square miles, or 2.3 *million* acres. If you visited one acre a day, without overlaps, it’d take you well over six thousand years to visit them all. (Or to look at it from another direction, if you allow yourself 50 years to see every acre of a graticule, then you’d need to cover almost 130 acres every single day.)

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  15. You know … you could modify the principle to use the multiple values from the Dow … say grab the current value once an hour, and have a set of way points.
    Or hash the whole part of the degrees in to give a different offset in each graticule rather than a moving dot grid…

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  16. I remember when the geohashing tool first came out and thought it was a fun idea! It is great to see how it has continued to evolve and spread.

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  17. There should be a visible-universe-hash, where the algorithm picks a random point in space every day. (or maybe a random star?)

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  18. I’ve heard Randall had Aids! that’ll teach him to fuck dirty fags in their loose assholes. Cunt.

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  19. I take it those guys were pretty close to the north pole already? Whether or not they were, that’s serious commitment. O_O

    Congrats guys 🙂

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