Geohashing has been great fun so far. There are hundreds of users on the wiki, and I’ve gotten to wander places like this:
There’s been a small change to the algorithm to deal with time zones. This change does not affect anyone in North/South America (excluding Greenland), does not affect Saturday meetup times anywhere, and does not change any currently known upcoming meeting times. The change:
For every location east of Longitude -30 (Europe, Africa, Asia, and Australia), use the Dow opening from the previous day — even if a new one becomes available partway through the day.
Put differently (the same functionally for everywhere except islands in the mid-Atlantic):
Consider any Dow openings published after noon local time to have occurred on the next day.
This is necessary to deal with time zone problems. For a lot of Europe, the Wednesday Dow opening was learned near sundown Wednesday, which meant they couldn’t use it to get to daytime meetups. For east Asia, they had to visit weekday locations the next day. A bunch of solutions were discussed, and I decided this was the cleanest.
The official map tool is being updated with the new behavior concurrently with this blog entry. The first coordinates that will be affected by it are Tuesday’s. Again, this does not affect anyone in the Americas.
Moving on — Saturday’s meetups are looking good! Today’s location in Boston was fantastic. I wasn’t planning to go, but it looked so interesting on Google Maps that we couldn’t resist checking it out. The picture above is one of several. Saturday’s meetup is in a less picturesque place than Friday or Sunday — suburban Hopewell. We’ll probably gather only briefly at the actual point, then head to the nearby state forest for walking or town center for food and such.
Also, good luck to phire, who was last seen on IRC an hour ago, leaving to mountain-climb to today’s coordinates in Christchurch, New Zealand. Congrats to the Denver graticules for getting organized so fast (and in a split city, at that!). And thanks to everyone for going along with this idea! The weekday trips have been great fun so far, and I look forward to getting the meetups going over the next few weekends!
cool this should solve most of our problems
Wonderful. Could a version be made with shifted graticules for people who happen to be bisected by the current system?
It would be nice if there were something more terrain-aware, or a way of “bumping” a point in case it “collides” with the ocean, as about 80% of the points near San Francisco will do.
Checked out friday’s boston location on google, thought by the looks of it that it wasn’t worth the effort. Terribly regretting not taking the 25 minutes of driving needed now. Tomorrow’s is closer, but I’m going to try to conserve gas. If I make it, I’ll be the terribly sweaty, out of breath guy on the bike. Only 11 miles of backroads and hills.
fluffy: It’s only about 60% water, I think
And you don’t need to go every day — I didn’t expect anyone would. I think a meetup every couple of weekends.is pretty reasonable. Yeah, you do have a lower rate of good coordinates, but it doesn’t stop things. A number of SFers — including the guy who wrote the reference implementation — go west by one to have somewhere to get to.
Besides, with all that beautiful mountainous country to the south, when you guys have a coordinate, it’s a great one.
alas halifax is fraught with water locations
Thanks for using my idea!
Apologies to Greenland…
Is there any way to account for transnational boundaries? Problem with the current graticules is that for places like Singapore (off the top of my head) you’re more likely than not have to traverse either a sea or make your way to a whole new country altogether, which you’ll see isn’t terribly ideal.
For the record, Friday’s comic was the best thing ever.
Thanks for the confirmation, and good luck to phire!
Denver is so getting that twister achievement. We may even do a human pyramid to show how organized we are!
Not going to lie…this is the most exciting thing to happen to me this summer. But boo to living on the coast where it keeps pointing me to the ocean
Regardless, I look forward to going to as many as I can.
Also: any Pacific Islanders. The multitude of them that frequent xkcd, I’m sure.
The weird thing is, that for today I get a totally different location for my Graticule with the tool, than I had found yesterday evening. (I live in the EST timezone, NL subdivision)
So right now I’m confused which one to go to. The one I found yesterday, or the one calculated today.
I’m not even sure if I can go today.
Click on the link for my tribute to this pearl of beauty that is geohashing.
You could just use a local exchange, London for Europe, Hong Kong or Tokyo for Asia….
MadJo, I assume you used two different dates, right? In that case I think you need to go to the location found on yesterday, Friday’s, date since DOW isn’t open today, so yesterday’s DOW is in effect.
Gotta say, the awards won me over. It’s just too bad that I live in a country with a majority of villages where the public transportation to said places is absolutely horried and that I don’t own a car.
@MadJo: Do you mean Australian EST? Friday’s Dow opened at 9:30am USEDT, or 11:30pm AEST Friday. If you calculated a coordinate for Saturday before that time on Friday evening, it would be incorrect. Please reference the coordinates posted on the wiki to sort out any discrepancies.
The new 30W Time Zone Rule described here (and on the wiki) eliminates these concerns.
reCaptcha: dancing HEAVILY…. haha
It occurs to me that much of the legwork for solving the problem of oceans, split cities, etc, has already been done. The solution I mention is for the US, but there are similar ideas for other countries. I’ll grant that the math and code will be more complicated. Use political boundaries, like congressional districts. For small countries, use the country itself. And so on. This doesn’t always solve the problem of some inaccessible inland areas.
Now that leaves the question of implementation, which is not easy, but collaboration on source code is good, right? If you don’t mind some areas being more likely than others, it’s possible to warp a square grid onto the district. If you do mind, then you can first pick a point in a bounding box, similar to the current system, and then, in a modular fashion, add the output of a PRNG to the coordinates until they fall in the district, *sorta* like the “rejection method” familiar to those who try to generate random numbers with an arbitrary PDF.
For those complaining of the water hit rate in place like San Fransisco you should try living in northern Canada, I could get to most places I’m getting with a Humvee! Oh well that’s part of living up north.
for points on the water, the easiest solution might just be to draw a straight line to the closest piece of mainland and declare the meeting there.
alternatively, get a boat
I don’t completely understand how you get the coordinates from the DOW thing and the date, how is it changed to hexadecimal? and is there a calculator anywhere that we can just enter the date in, and then be off?
How about subdividing the entire scheme by 10? Ten th-degree regions.
Then the hashed location each day will never be too terribly far away.
Next few spots for Cleveland are in the lake, great opportunity for anyone with a boat to get the coveted Water Geohash award…
Subdividing regions will mean that there will be less people at a location, they’re already pretty small to begin with.
Oh finaly this works for europe! i hope that I will find some crazy guys to geohash with
Nice work
Algorithm not so good when co-ordinates are in sea.
Oh my, if I had the money to fly to Boston to come to your meetups I would! Man, I would love to meet you Randall. And also, I live in the frozen north redneck central. There are probably only about 5 other people who have heard of xkcd and most of them work with me. I am a shameless Munroe promoter.
Geohashing, dead link due to capital G in url…
Using Congressional districts is a terrible idea; ever heard of Gerrymandering?
My area is 80% water. Can you think of an official solution for coordinates in the water, Randall? Maybe something like day % 4 to obtain a direction (North, South, East or West) and then go in that direction from the algorithm result until you hit coastline, and that point becomes the meetup location?
Sorry, I mean day_of_the_year % 4. And I apologize if this was suggested by someone else before, but I don’t read all these comments ^^
http://www.twitter.com/BostonGeohash
Perl script is finished. I set up cron to (hopefully) run it at 10 AM every morning. Now you don’t have to check the website, just get updates sent to your phone. Use it, I worked hard to get this done…
On Friday I was all pumped for Saturday’s meetup in Devil’s Lake State Park, north of Madison, WI, because I’d already been planning to go there.
And then I realized I hadn’t changed the date to Saturday. Turns out the meetup was closer to home but not in an interesting location.
Thanks for the luck, but it didn’t seam to be enough.
http://wiki.xkcd.com/geohashing/2008-05-24_-43_172
i have this problem: every location i get is in the middle of the pacific ocean. and while i consider sailing an impressively interesting activity, the lack of sailing material (namely a sailing boat) tends to render my excursions physically impossible. by the way i live in lima, peru, so yes, i’m aware i’m probably the only one having this problem so far
Wiki link in post is broken (“G” is incorrectly capitalized).
Your link above is 404. You typed in http://wiki.xkcd.com/Geohashing but I think you meant http://wiki.xkcd.com/geohashing instead.
Is it possible for someone to write a script to tell an RSS feed of the locations for all the lazy blobs like me out here. not just for boston but for each box, with a google earth link too?
how many total locations are there? because if you split it too many times will mean its nearly completely unlikely that people will meet.
Finally i can calculate random flightplans for my skyship. Anyone else in the bristol area?
well are there any europian meetups? i found some people on frappr @ xkcd maps, but there is not many people up there
I actually was in range of this past Saturday’s point, as it was land for once. Unfortunately, the point was on a nearby Air Force base – right on the airstrip – and my got towed that day too, so my plans were kinda shot…
The updated coordinate system is a good idea. I’m glad our buddies outside of NA will be able to actually participate.
Edit to this sentence in my post above:
“and my car got towed that day too, so my plans were kinda shot…
Huzzah for the “Set Default Location” button. While this wasn’t a huge problem for a Clevelander such as myself, it does mean less time finding the location and consequently more time geohashing.
@Chris: Yes, I have, and people make a much bigger deal of that than they need to. The districts are not that difficult to travel in, particularly if you only have a car. Furthermore, they provide very interesting test cases for non-convex geometry.
Anyway, I was just putting it out there, since people don’t seem very satisfied with the solutions presented already…probably because they require a little bit more effort/money/time, rather than more code. It’s a tradeoff.
On the other hand, an algorithm to keep meetups in one country would be impractical for Western Europe (except probably the UK and Ireland and some other islands). There are no border controls within the EU, so you can travel freely from one country to another. Sometimes you may not even notice that you crossed the border if you don’t pay attention.
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It would be interesting to see what the distribution of sites in a square is for a range of Dow values. Is the whole square covered?
Or if there is any correlation between the geohash location and the value for the next day. Or meetups could be used to discuss insider trading.
Is it possible to just eliminate the water from the map you use? ie: all maps used will just be landmasses?
Not sure how that would work since it wouldnt be tied into google maps.. just wondering though…
Sadly this fails most of the time for San Diego.