Is there a free world cities DB?

[Nicholas Paldino [.NET/C# MVP]]

Sharon,

You can probably get the latitude and longitude using Google Maps or
Live Search (I know that Live Search has a web service you can perform a
search on, and it will return lat/long coordinates in return).

You will have to go to another service to get time zone information
though.

 

[Mark Rae [MVP]]

I'm looking for a free world cities data base that includes:
Longitude, latitude and time zone.

http://www.google.co.uk/search?hl=en&rlz=1T4GGIH_en-GBGB220GB220&q=world+cities+database+free&meta=

 

[Sharon]

Hi all,
I'm looking for a free world cities data base that includes:
Longitude, latitude and time zone.
Thanks,
Sharon.

 

[Sharon]

Hey Mark,
I did a Google search, as I always do, before posting this question.
None of the free DB's offer a time zone field.
I haven't even found a commercial one with this field.
Sharon.

 

[Sharon]

Thanks for the reply.
I'll try it.

Sharon,

You can probably get the latitude and longitude using Google Maps or
Live Search (I know that Live Search has a web service you can perform a
search on, and it will return lat/long coordinates in return).

You will have to go to another service to get time zone information
though.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

Hi all,
I'm looking for a free world cities data base that includes:
Longitude, latitude and time zone.
Thanks,
Sharon.

 

[Fred Mellender]

You could construct this using information from various WebPages.
E.G.
File 1: get a list of the tz zones:
http://en.wikipedia.org/wiki/List_of_tz_zones_by_country
(or download the source of this (see
http://en.wikipedia.org/wiki/Tz_database).

File 2:
find a list of cities with their long/latitudes:
e.g. http://www.realestate3d.com/gps/world-latlong.htm

File 3:
find the current times of some world cities. E.G.
http://www.timeanddate.com/worldclock/full.html?sort=2

Extract the information from these WebPages (save the HTML source, write a
program to extract the data). Then merge the data you want.

You should be able to figure out the time zone for a city X by looking up
its current time in File3 and finding a city Y with the same time (also from
File 3), that is also in File 1 (which lists the time zone of city Y, and
will hence be the TZ of X too).


Just an idea.....

 

[Mark Rae [MVP]]

You could construct this using information from various WebPages.
E.G.
File 1: get a list of the tz zones:
http://en.wikipedia.org/wiki/List_of_tz_zones_by_country
(or download the source of this (see
http://en.wikipedia.org/wiki/Tz_database).

Wikipedia cannot be relied upon under any circumstances...

 

[clintonG]

Wikipedia cannot be relied upon under any circumstances...

Wikipedis ia very reliable as a starting point. As much as I dislike quoting
politicians Ronald Reagan said "trust but verify."

<%= Clinton Gallagher
NET csgallagher AT metromilwaukee.com
URL http://clintongallagher.metromilwaukee.com/

 

[Sharon]

Thanks for your reply Fred.
I cannot use this data.
I should have mentioned that the format I need is:
Longitude / Latitude: Long (42.5333333, 1.5333333)
Time Zone: Integer (+1, -4)

I found a good free cities database with longitude and latitude here:
http://www.maxmind.com/download/worldcities/
Now all I need is the time zone.
Regards,
Sharon.

 

[Abdullah Kamran]

I have found a method to find the timezone using longitude of a place from somewhere. I tried it to do some calculations and found it working, it is not very accurate though (needs some improvements)

The timezone changes every 15 degrees on longitude either way. The formula to find timezone is:

(longitude/15) * 3600;

This will give you timezone (or time differnce from GMT) in seconds. And can be used in calculations.

Hope this will help.

Regards,

A Kamran

EggHeadCafe - .NET Developer Portal of Choice
http://www.eggheadcafe.com

 

[Michael A. Covington]

What you are calculating is local mean time, not zone time. Time zones are
established by law, usually follow 1-hour increments, and have boundaries
that are not straight lines.

For example, Atlanta (longitude 84 west) is 5.6 hours behind GMT according
to your formula, but in fact it is officially 5 hours in the winter and 4
hours in the summer.

Local mean time is almost always within 1 hour of official (standard) zone
time.