Location detecting techniques for IP addresses

Question

What are the location detecting techniques for IP addresses?
I know to look at the
$_SERVER[\'HTTP_ACCEPT_LANGUAGE\'] (not accurate but mostly useful to

Answer 1

One way in which these databases are compiled is from whois information. For example, to determine the location of 69.59.196.211:

fmark@home:~$ host 69.59.196.211 211.196.59.69.in-addr.arpa domain name pointer stackoverflow.com. fmark@home:~$ whois stackoverflow.com

Whois Server Version 2.0

Domain names in the .com and .net domains can now be registered with many different competing registrars.

> Registrant: stackoverflow.com llc
410 Clayton Ave El Cerrito, California 94530 United States

Obviously this isn't hugely accurate, so more sophisticated techniques are allegedly used.