Geo Visitors - how does it work?

The visitors of my forum are asking how the Geo Visitors tool is working. I know it works using IP databases, but how can this IP databases actually be that accurate, I mean even detecting the smallest town? Can anybody refer me to a newbie friendly site with a good explanation?

 

ISPs get assigned IP ranges. There are many ISPs and some of them sublet their services down to smaller ISPs again. That way you can go all the way down to a small area by keeping a global database of which ISPs get assigned which IP ranges.

 

Thanx for the quick answer! I'll post your explanation now on my forums.

 

OK, you can get written permission from my Intellectual Property lawyers by PMing me j/k

 

The one I use on Map Visitors http://www.mp2kmag.com/mapvisitors is http://www.hostip.info/ .. Virtual Earth also has a database built in that I should be using.. I think DP mentions somewhere with another tool that they are using a popular commercial database. It does not appear that hostip.info is very good outside the US.
Eric

 

I have been trying to get MS's Locate.aspx function to work with MapVisitors

( now at http://www.mapvisitors.com )

More information about MS's function at --
http://viavirtualearth.com/vve/Articles/ObtainingVisitorLocation.ashx

However it requires that some JavaScript be run on the clients computer, and I need to be able to do it all in PHP.

I don't think I can run any JavaScript on the client's computer because I am writing an image.

Any ideas?

Thanks,
Eric