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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, a-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/Asia date handling still under discussion, see Talk:Main Page.
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. You can use this wiki to document the coordinates (geohashes) you've been to.
Unless you can 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!
When the coordinate falls somewhere dangerous or illegal to reach, use your judgment. If the coordinates are in an obviously unreachable place, the meetup is postponed until a better day.
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.
Implementation
A sample interactive coordinate calculator can be found here: [1] A reference implementation is available here: view download
A python implementation:
import md5, datetime, struct, urllib, re
date = datetime.date.today()
djia = urllib.urlopen(date.strftime("http://irc.peeron.com/xkcd/map/data/%Y/%m/%d")).read()
sum = md5.new("%s-%s" % (date, djia)).digest()
print struct.unpack(">Q", sum[0:8])[0] / (2.**64), struct.unpack(">Q", sum[8:16])[0] / (2.**64)
Active Graticules
- Region/Graticule pages named "City Name, Country (or state)" where "City Name" is the most major (by population) urban center contained within it.
Australia
-35, 138 (Adelaide, Australia)
-38, 145 (Melbourne, Australia)
-35, 149 (Canberra, Australia)
-28, 153 (Brisbane, Australia)
Europe
West to East (and North to South):
55, -4 (Glasgow, United Kingdom)
55, -3 (Edinburgh, United Kingdom)
51, -3 (Bristol, United Kingdom)
54, -2 (Middlesbrough, United Kingdom)
52, -2 (Birmingham East / Leicester / Coventry, United Kingdom)
51, -2 (Swindon / Oxford, United Kingdom)
50, -2 (Southampton / Portsmouth / Bournemouth / Isle of Wight, United Kingdom)
51, -1 (London West, United Kingdom)
52, 0 (Cambridge, United Kingdom)
51, 0 (London East, United Kingdom)
51, 4 (Rotterdam / Antwerpen, Nederland / Belgium)
51, 5 (Eindhoven, Nederland - plus wat België)
52, 6 (East of the Netherlands, plus some small parts of Germany)
North America
West to East (and North to South):
61, -149/-150 (Anchorage, Alaska)
37, -121 (San Francisco: East Bay, San Jose)
40, -111 (Salt Lake City, Utah)
33, -111 (Mesa-Scottsdale-Chandler)
50, -105 (Regina, Saskatchewan, Canada)
40, -105 (Denver/Boulder, Colorado)
21, -103 (Aguascalientes, México)
30, -96 (College Station, Texas)
39, -94 (Kansas City, Missouri)
45, -93 (Minneapolis NW, Minnesota)
44, -93 (Minneapolis SW, Minnesota)
30, -92 (Lafayette, Louisiana)
30, -91 (Baton Rouge, Louisiana)
30/29, -90/-89 (New Orleans, Louisiana)
39, -86 (Bloomington, Indiana)
36, -86 (Nashville, Tennessee)
42, -85 (Grand Rapids, Michigan)
29, -82 (Gainesville, Florida)
35, -81 (Gastonia, North Carolina)
40, -80/-79 (Pittsburgh, Pennsylvania)
35, -80 (Charlotte, North Carolina)
43, -79 (Toronto, Ontario, Canada)
38, -78 (Shenandoah Valley, Virginia)
35, -78 (Raleigh, North Carolina)
38, -77 (NW and SW DC, Northern Virginia, Bethesda MD)
38, -76 (DC east of 4th St {N/S}E, Bowie MD)
45, -75 (Ottawa, Ontario, Canada)
42, -72 (Springfield, Massachusetts)
41, -72 (Hartford, Connecticut)
42, -71 (Boston, Massachusetts)
41, -71 (Providence, Rhode Island)
44, -63 (Halifax, Nova Scotia, Canada)
South America
Recent Events
2008-05-17 37 -122 -- Dan, Emad, and Randall reached the San Francisco coordinates in a successful test.
2008-02-24 45 -122 -- NoTerminal and Drache reached this point as part of an early test while coming up with the algorithm.
Next Upcoming Day
2008-05-21 -- The coordinates for Wednesday, May 21st are available.
Next Saturday
2008-05-24 -- The coordinates for Saturday, May 24th will become available on Friday about 9:30 AM EDT, when the Friday Dow Jones opening price is published.
See TimeandDate.com for dow opening time in local timezones
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
