Olson timezone by population
January 18, 2010 2:36 PM   Subscribe

Where can I find a list of Olson timezones ordered by population?

I found this bit of code, but it is in Perl which I'm not too familiar with. I tried to build it, but it complained about some dependencies missing.

This list must exist somewhere in some form. It doesn't need to be 100% accurate, as I'm sure the data is constantly changing. I just need a good approximation. Any help would be appreciated. Thanks!
posted by whiskeyspider to Computers & Internet (7 answers total)
I don't know where you can find an answer, but I've asked the same question.
posted by madcaptenor at 6:13 PM on January 18, 2010

The Perl code that you reference just uses the order of the zone.tab file from zoneinfo. The Wikipedia page uses the same order. It's sorted first by geographical region, and then by population within each region. (This is handy for user interfaces that provide a list of countries, and then a list of timezones within the user's selected country with the most populous zones first.)

Neither source will provide the entire list sorted just by population. Sorry, I don't know a good way to answer that question.
posted by mbrubeck at 7:26 PM on January 18, 2010

I have mused before on how the zoneinfo database contains a special entry for minuscule Vevay, Indiana, a holdover from the dark days of Indiana Time (since simplified).

Vevay itself has a population of around 2,000 (bizarre in comparison with other zoneinfo entries like Toronto, Warsaw, Darwin, etc.), so that could be your number---certainly it's a contender for the low precincts of your scale. But the zoneinfo entry would presumably apply for all of Switzerland County, Indiana, population 9,000 or so. Which number would you use to sort?

Unfortunately, I think the problem is harder and less well specified than you might expect. What I might do is the following, assuming you're good at writing perl or the like. Using the Wikipedia page you linked to, follow the link to each place name (e.g. Vevay, La Rioja, etc.). In the source code, search for the word "Population" and then find the number nearest to that word in the surrounding text.

OR: There are a couple hundred timezones? Just work with a friend. Have them follow the links and tell you the population while you put the entries into Excel. Then sort. Should take you about half an hour maybe.
posted by tss at 10:13 PM on January 18, 2010

tss, that won't work because the "place name" is just a representative sample of a general area. For example, America/Los_Angeles covers the entire US Pacific time zone (approximately 50 million people), but if you just look up the population of Los Angeles (12.9 million metro area) you would come away very short.
posted by Rhomboid at 7:22 AM on January 19, 2010

Although, you could probably approximate an answer by doing the reverse: get a list of the 500 (or 1000? 10000?) most populous cities worldwide and spider each of their wikipedia pages and look for what time zone each city observes. That kind of rough sampling will result in many timezones with zero population though.
posted by Rhomboid at 7:28 AM on January 19, 2010

Wikipedia has lists of what's in what time zone: see UTC-5 (which is US/Canadian "Eastern time") for an example.

From a quick look through that data, it seems like most countries have one time zone. Those that have a significant population in multiple time zones are, from west to east, Canada, the United States, Mexico, Brazil, Argentina (really! one province in the middle of the country is special), Democratic Republic of the Congo, Russia, Kazakhstan, Indonesia, Mongolia, Australia, and maybe China. And in most of those countries it looks like timezone boundaries break along state/province boundaries; the situation in the US where lots of states are actually in more than one time zone seems to be rare. (But I could be wrong; Wikipedia might just document the US situation better.)

China is a weird case, because it officially has one time zone (UTC+8) but unofficially much of the west uses UTC+6 because they (understandably) don't want to use the same time as Beijing.

There aren't really as many current time zones are it looks like from the zoneinfo file; a zoneinfo time zone includes a daylight savings time rule, will separate places that used to be in different time zones but are now in the same one, and attempts to include at least one time zone for each country. In other words, I think you might be asking the wrong question, because Zurich, Prague, Berlin, Copenhagen, Paris, Budapest, etc. are all listed as separate zones even though it is the same time in all those places.
posted by madcaptenor at 7:56 AM on January 19, 2010

Forgot to mention: Wikipedia has a sortable list of zoneinfo time zones which might help get your bearings if you want to make decisions about which time zones really count as "different". Also there is a series of articles "time in X" where X is usually a country.
posted by madcaptenor at 7:57 AM on January 19, 2010

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