Talk:Main Page/Archive 2

Talk:Main Page Archives

• Archive
• Archive3
• Archive 1
• Archive 2
• Archive 3
• Archive 3/wgh/wgh/wgh/index.php
• wgh/wgh/index.php

See also: Current Discussion

Use of one degree grid sucks

The usage of integer lat/long as the grid for this is really simple but it doesn't perform well. For example, the DC metro area is split into four zones each which contain a small populated area and a large area no one wants to travel to. Alternatively, consider Milwaukee Wi, where there is a 80% chance of the meeting location being in the middle of Lake Michigan, likewise for a number of other coastal cities.

Instead what should be done is someone should search for a tessellation of the world where each tile has the same area as a 1deg/1deg grid but optimized on the following criteria:

• Tiles should not span national borders.
• Where the boundary lines avoid areas of large population
• Tiles should not simultaneously contain large amount of water and non-trivial numbers of people
• Any others?

Once a tessellation is found the hashing could just be an index into each tile. It would be somewhat more complex, and require knowing the tessellation, but it's not like anyone is doing MD5 in their heads.

Perhaps a contest could be held for tessilations? People could compute ones then argue why theirs were the best. ;) --Gmaxwell 22:01, 22 May 2008 (UTC)

People don't want to travel there? I wouldn't be quite so sure about that. Geocaching is rather popular in large foresty areas, and the visited hashes we've seen so far were busy enough even though they were in the middle of nowhere. I actually see your point, but I think that it's not possible to create anything better than this which isn't particularly difficult or annoying to implement. As for the national borders - I'm fairly happy that's not too much of an issue here in Europe ;) Nazgjunk 22:07, 22 May 2008 (UTC)

At least you can expect find something at a geocache. Seems to me that the value of a geohash is meeting the other hashers. When the selected location is often multi-hour drive (due to geographic features and lacking roads) into an unpopulated area it's likely that no one will show. So people will lose interest and be aware of it the few times it is in a good location. With something around 300 geocaches found I think I've only run into other geocachers three or four times or so, and most geocaches are in locations far less random than geohash locations.

I think the people who will spend hours getting to an adverse location will really enjoy the conversations they'll have on the days when they do run into someone. And I think you may be underestimating just how geeky xkcd readers may be -- to me the adverse locations sound most attractive. For those who'll go only when "it is in a good location," there's still the joy of the hangfire of not knowing when that will be until just beforehand. I like the idea of multiple people having determined in their heads to partake in an adventure of unknown complexity, even subject to whatever personal qualifications, where the fruit of the mutual determination doesn't materialise until the adverturers converge on the target. Lastly, I guess geocaching doesn't have any goal of meeting others, and wallclock time is not part of the target, so it doesn't sound surprising you'd rarely run into others? —Christian Campbell 17:27, 23 May 2008 (UTC)

Even when crossing borders is easy, differences in available data might lead to different tessellation rules. I know where to get good population data for the US, but I don't personally know how to get the same data for Mexico.  :)

As far as complexity goes.. geohashing already requires an MD5 .. is indexing into a big table of polygons that much harder?  :) (though the MD5 should be dropped.. if the random seed is random enough, just xoring the digits should be more than random enough...) --Gmaxwell 22:24, 22 May 2008 (UTC)

No one claims the DJIA is very random. But with the MD5, even the slightest change produces a completely new point. That's why I'd argue the MD5 should never be dropped. Zigdon 23:57, 22 May 2008 (UTC)

In Europe, meeting with people from other countries only makes it more fun. Integer grids are good, you can always go to another graticule if it's closer. Nobody says you should take your home's location, you can travel to another location and take the geohash there. --FrederikVds 13:56, 23 May 2008 (UTC)

You're missing the point. See Lowman's post below. Gormster 15:33, 23 May 2008 (UTC)

I don't think so. Maybe you understood me wrong. What part of the point am I missing? --FrederikVds 17:33, 23 May 2008 (UTC)

Saturday's meetingpoint

I was wondering. Is the saturdaymeetingpoint calculated with the date of saturday and the dow opening of friday? Or is the date you use always the date of the dow opening? --Evo-- 13:22, 23 May 2008 (UTC)

My understanding is that you hash in Saturday's date, so that the locations for Fri, Sat & Sun are all different, and are available at 09:30 EDT on Friday. Speaking of which, could someone post the Saturday location? I don't have a hasher. AshleyMorton 13:40, 23 May 2008 (UTC)

Yes, that's right... Current date, most recent DOW opening. Speaking of the hasher/locator, is anyone else having trouble with the peeron one? everytime I hit update it jumps the point around a couple times. I'm at a loss for where I'm supposed to go. --WokTiny 14:06, 23 May 2008 (UTC)

For some reason it adds a few zeros to the Dow Jones every time you click calculate, screwing up the algorithm. StJimmy 14:22, 23 May 2008 (UTC)

I'm not seeing this. Steps to reproduce the problem, or is it fixed? --Xkcd 16:40, 23 May 2008 (UTC)Xkcd

I'm still seeing this. Just go to the page in Internet Explorer and either move the map, zoom, or hit the "Update" button again. The coordinates and the marker will change. The bug doesn't show up in Firefox but it does in IE7, I don't know about other versions of IE.--Ahecht 18:37, 23 May 2008 (UTC)

Cookie/Bookmark?

Is it possible to set one's browser to always start at a certain point when viewing the geohash calculator? The first time I visited it (when I was at home in Berkeley), it started out zoomed to my home graticule. Now that I'm at my parents' (in Los Angeles), it defaults to the Boston graticule. I don't know if this is something to do with our respective internet providers or if something has changed with the mapping program, but it would be great if there were an option to default the map to the current view (whatever that may be). If there's already something that I'm missing, someone can just enlighten me. Thanks!!! Darcy 02:15, 26 May 2008 (UTC)

Yes, that would be useful. Done. Zigdon 06:56, 26 May 2008 (UTC)

Awesome, thank you! Darcy 16:24, 26 May 2008 (UTC)

Using the Dow is a Bad Idea for anyone east of the US

Please consider time zones next time :( - some poor european guy

See 30W Time Zone Rule. There's already been a whole load of discussion about us non-americans, and the final decision was that if you in Europe, Asia, Australia, or just about anywhere that isn't North or South America you use the prior day's Dow. Just means you get a bit more warning that the Americans. --Psud 11:25, 26 May 2008 (UTC)

And the previous discussion: Talk:Main Page/Archive#Europe Time Zones problem --Psud 11:30, 26 May 2008 (UTC)