Geohashing

May 21, 2008 12:04 AM

Geohashing: "As you may have noticed, today’s comic contains an algorithm for converting dates into local coordinates. For a given day, you can calculate what that day’s coordinate is for your region. Dan has put together a tool for calculating a day’s coordinates and show it using Google Maps."

"Note that you can’t calculate a day’s coordinates before the stock market opens on that day (about 9:00 EST) — except for weekends and holidays, when it uses the most recent opening price."

More info on the XKCD geohashing wiki.

posted by Anything (29 comments total)

You know, as happy with himself as Randall might be, he is really does do the most imaginative things. It's funny to think how wildly popular and (somewhat) influential a guy with a webcomic has become. Welcome to the future!
posted by lattiboy at 12:25 AM on May 21

This is exactly what the internet is for.
posted by Pope Guilty at 12:44 AM on May 21

Flagged as awesome.
posted by DreamerFi at 1:53 AM on May 21

My region is quite amusing, in that it's about half Puget Sound, and putting in the last few days worth of coordinates would have required a boat a lot of the time. Still, pretty fun.
posted by maxwelton at 3:03 AM on May 21

Is it just me, or could this more easily be accomplished with a local map and a dartboard?

Is going to a random location that may or may not actually be interesting... fun?
posted by Mr.Encyclopedia at 3:30 AM on May 21

Well this is pretty inordinately cool. As an idea I think it's crazy-awesome, but when it comes to actually visiting sites I'm not sure how crazy-awesome it will actually be. What with gas prices the way they are. And then maybe not being able to actually get there which would surely instill a deep sense of disappointment and inadequacy for definitely people who aren't me.

Then again I may just be really jealous that I won't have the time for some good solid three months to actually use this tool.
posted by six-or-six-thirty at 3:52 AM on May 21

Mr. Encyclopedia I don't think the purpose is necessarially to go somewhere, as it is to be an interesting example of hashing which is a sufficiently odd aspect of computer science that a lot of students have a hard time getting it at first (especially WRT hash tables) [1] So its a potentially interesting teaching tool.

Also, if you did want to put something somewhere, and have a third party know where it was, a function similar to this one could be handy. All they'd need to know is the date and the function. Obviously if it was something secret you'd want a different function, but there's a large variety of variables one could toss in other than the Dow. The smog index for LA on that date, the temperature in Moscow, the number of comments on the metafilter post made closest to midnight on that date one year ago, etc.

[1] At least during the CS class I took in which the topic was introduced around 70% of the class didn't really get the concept until they'd been over it several times. Dunno if that's normal or if my class was just full of dummies.
posted by sotonohito at 3:55 AM on May 21

As a side note I also very much like the idea that you can't know your coordinates before 9 am (generally speaking). So you can't really plan it out beforehand, and it would feel a lot more spontaneous. Another part of the idea that I love and shake a frustrated fist at all at once.
posted by six-or-six-thirty at 3:55 AM on May 21

Is it just me, or could this more easily be accomplished with a local map and a dartboard?

You won't meet anyone else that way.

I don't think the purpose is necessarially to go somewhere

Oh, I think it is.
posted by grouse at 4:10 AM on May 21

The mutating coordinates give a spontaneous feel, it's true. For a more permanent and mystical one, try an algorithm that maps all lat/lon coordinates onto attractors. It would also be cool to have each person follow the right trajectory (in the mathematical sense) to get there.
posted by DU at 4:23 AM on May 21

Anyone, especially those not yet or already in college, who is excited by this idea should consider studying computer science. The discussion of an algorithm is the start of what separates computer science from information technology, as well as other science and math fields. (And just cause you aren't interested in geohashing, doesn't mean you aren't interested in CS.)
posted by about_time at 4:27 AM on May 21

Doesn't he know that MD5 is no longer considered secure?
</faux_snark>
posted by scruss at 4:49 AM on May 21

Is it just me, or could this more easily be accomplished with a local map and a dartboard?
You won't meet anyone else that way.

As far as I can tell, you would only meet someone with this algorithm if you both started at the same area (what's one point of gps equivilant to? 200km?) and left on the same day, using the same dow opening figures (the cartoon only uses it as an example and only suggests the opening OR most recent, with leaves more room for error)

I'm not really seeing the appeal. It's a way to generate random gps coordinates. If it was more universal then it might be cooler, but even then, what are the chances someone in your neighbourhood is an XKCD fan, and on the same day as you decides to go exploring with their GPS unit, without screwing up their math in the process or using a slightly different dow figure?

I liked the last GPS adventure better.
posted by Dillonlikescookies at 5:08 AM on May 21

Doesn't he know that MD5 is no longer considered secure?

I don't think a collision would be disastrous here. :-P

However, as much as I love xkcd, I'm sure as heck not driving 62 miles for it.
posted by musicinmybrain at 5:08 AM on May 21

what are the chances someone in your neighbourhood is an XKCD fan, and on the same day as you decides to go exploring with their GPS unit, without screwing up their math in the process or using a slightly different dow figure?

In a major metropolitan area in the near future, pretty good, especially since there's a calculator available. In a lot of cases, you could even do it with Google Maps and no GPS.
posted by musicinmybrain at 5:11 AM on May 21

Ah, i see - regular meetups on saturdays at 4. Well, yeah. The problem is in small areas you run the risk of noone being there, but if you make it wider then people have to drive further. tricksy.
posted by Dillonlikescookies at 5:11 AM on May 21

what are the chances someone in your neighbourhood is an XKCD fan

In my semi-academic, high-tech/scientific office, practically everyone is. That said, I'm not driving 50 miles to the meetup point. I need a version of this that generates room numbers.
posted by DU at 5:19 AM on May 21

DU, use the first valid room number in a decimal representation of the hash.
posted by fantabulous timewaster at 5:48 AM on May 21

what are the chances someone in your neighborhood is an XKCD fan

During the school year, pretty high. But CMU and Pitt are out for the summer by now so all the geeks are back at their suburban homes. He should have done this in September when geeks tend to be more concentrated in urban areas.
posted by octothorpe at 5:58 AM on May 21

Comic, as in funny? or comic as in I have this webspace I have to fill with something?
posted by garlic at 6:55 AM on May 21

Meetups are Saturday at 4pm, but, which days coordinates do they use? Friday's? Or the "best" coordinates from the preceding week?
posted by knave at 7:02 AM on May 21

That comic is hilarious. Man. Still laughing. Almost as funny as yelling "Free Tibet" at a Chinese rock concert. It would interesting to see him get away from the over-designed figures and adopt a slightly more minimalistic look. Think of the time it takes to create each intricately detailed panel!
posted by BeerFilter at 7:17 AM on May 21

He's used the comic a couple of times to advertise, basically, a new idea he's had that he explains in more detail on the blog. I personally don't have issue with that, especially since the strips he make that are more like your typical comics are consistently good. In the end, it's his space and medium to do with what he wants.
posted by six-or-six-thirty at 7:50 AM on May 21

That's a pretty large area. I'll be damned if I'm driving that far just to be "internet cool."
posted by jeblis at 8:49 AM on May 21

I will have none of this Worlds Colliding bilge. The hot side stays hot, the cool side stays cool.

Unless I am ever in PDX when a meetup is happening.
posted by everichon at 9:40 AM on May 21

Actual Geohashing, which provides some actual utility.

Wikipedia Link
posted by ursus_comiter at 1:37 PM on May 21

oh dear... now I want my own GPS unit and a quick dashboard applet to grab a value and output a GPS stream to Google Earth.

Perhaps this will do as a good GPS unit... since I'm a bicyclist.
posted by Sam.Burdick at 9:26 PM on May 23

This being the first Saturday we were interested we were disappointed to see how far away the day's coordinates were.

It'd be fun to take over a Saturday with a mefi meetup, if at 9 am the coordinates looked feasible, of course.
posted by artifarce at 7:04 AM on May 24

Today's Boston Geohash
posted by grouse at 7:04 AM on May 24