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The Algorithm

Coordinates for Portland^{[citation needed]} on January 1, 2008 (taken from this tool)

NoTerminal and Drache at the February 17th coordinates

Welcome to the GeoHashing Community Wiki. Geohashing is a Spontaneous Adventure Generator, brought to you by xkcd. If you are already familiar with GPS and xkcd, then proceed onwards!

What is this?

xkcd comic #426 contains an algorithm that generates random coordinates across the country¹ every day.

These coordinates can be used as destinations for adventures, à la Geocaching. They can also be used for local meetups.

For a little more interactive discussion consider joining the #geohashing IRC channel on Foonetic.

^1. Europe/Africa/Asia date handling still under discussion, see the talk page for proposed standard.

How it works

Play with the coordinate calculator here: http://xkcd.com/geohashing

Every day, the algorithm generates a new set of coordinates for every region. They are randomly placed -- they could be in the forest, in a city, or on a mountain^{[citation needed]}. You can use this wiki to document the coordinates (geohashes) you've been to.

Unless you can accurately predict the stock market, you can't figure out what the coordinates will be ahead of time. You can first calculate a weekday's coordinates at about 9:30 AM (Eastern), and on Friday morning you can calculate the coordinates for each day that weekend.

If you go on Saturday afternoons, you might encounter other xkcd readers. Bring games! ...or you might not. Bring books!

Absolutely do not litter. However, creating some kind of a marker out of nearby materials (i.e. cairn of stones, blair-witch-style 'stick figures', etc) is acceptable/encouraged^{[citation needed]}.

When the coordinate falls somewhere dangerous or illegal to reach, use your judgment. If the coordinates are in an obviously unreachable place (e.g., ocean), the meetup is postponed until a better day. Alternatively, rent a boat and win the Water Geohash achievement.

Official Meetup

The official xkcd meetups happen every Saturday afternoon at 4:00 PM (local destination time). If the coordinates for your area are in the ocean, a military base, or somewhere otherwise unreachable, that meetup is of course postponed. Unless, of course, you own a boat, are a soldier at said military base, or are James Bond. If you can, record who's there, take pictures, and post them here.

Implementations

The original sample interactive coordinate calculator can be found here: [1] A reference implementation is available here: view download

MediaWiki half-implementation (for use by template creators).

Active Graticules

See Active Graticules for a list of graticules with active users in them.

Recent Expeditions

• 2008-05-26 -- The coordinates for Monday, May 26th are available (no trading -- Memorial Day^{[citation needed]}).
• 2008-05-25 -- The coordinates for Sunday, May 25th are available.
• 2008-05-24 -- The coordinates for Saturday, May 24th are available. Convenient city graticules in the U.S. include: San Antonio, Cleveland, Portland, and Baltimore.
• 2008-05-23 -- The coordinates for Friday, May 23rd are available^{[citation needed]}.
• 2008-05-22 -- The coordinates for Thursday, May 22nd are available.
  • 2008-05-22 39 -105 -- This geohash has been reached in the very active Denver graticule.
  • 2008-05-22 32 -117 -- This coordinate in the San Diego, California area was reached by Somnivore.
  • 2008-05-22 42 -89 -- This geohash was reached in the Stoughton, Wisconsin graticule by Alric.
  • 2008-05-22 40 -96 -- This geohash was reached in the Lincoln, NE graticule by Spike and crew.
  • 2008-05-22 44 -93 -- This geohash was reached in the Southern Minneapolis, MN graticule by Chris and Abi.

• 2008-05-21 -- The coordinates for Wednesday, May 21st are available.
  • 2008-05-21 42 -71 -- Randall and cousin Annuska reached the Boston coordinates and photographed a spider.
  • 2008-05-21 54 -2 -- Nick reached the Carlisle coordinates.
• 2008-05-17
  • 2008-05-17 37 -122 -- Dan, Emad, and Randall reached the San Francisco coordinates in a successful test.
• 2008-02-24
  • 2008-02-24 45 -122 -- NoTerminal and Drache reached this point as part of an early test while coming up with the algorithm.

See the Expedition Archives for older events.

Today's Sites

2008-05-23 -- The coordinates for Friday, May 23rd are available. ^{[citation needed]}

Next Saturday

2008-05-24 -- The coordinates for Saturday, May 24th has been published

See TimeandDate.com for Dow opening time in local time zones.

Note that complications may arise due to timezones - not to mention both spatial and temporal abnormalities. (I.e. Individual results may vary.)

"Bugs"*

On Internet Explorer, the application at xkcd.com/geohashing can give incorrect results, since clicking the "update" button repeatedly will add extra zeroes to the right of the decimal point on the stock market value, leading to a different hash.

Due to the relative start locations used, if you happen to live close to a coastal region you may require a boat in order to successfully reach the calculated coordinates.

In addition, due to the relative start locations used, you may require a passport to successfully reach the calculated coordinates.

* Bugs is in quote marks due to the fact that it is not an error, just an additional challenge, if you need additional equipment to reach the indicated location. In theory one would expect the ability to reach the indicated destination with naught but a map/GPS unit (and the internet).

Related Projects

• Geocaching: Global GPS cache hunt
• Geodashing: Monthly points, randomly created
• The Degree Confluence Project: visiting every integer latitude/longitude crossing point in the world