When users are at known undergroudn locations, such as tube stations they often do not have a GPS signal, as the radio waves from the satellites required cannot penetrate the earth, this RFC suggests providing GPS locations over WiFI using remote IP detection for a server to respond with the correct name of clients location and the clients GPS location.
Extending this to those without WifI access the standard goes one stage further, by offering a hidden wifi network with a standard name, such as .location. The principle being that mobile devices can look for this network in cases where GPS data cannot be collected. It is hoped that this will allow those using mapping services to know where they are when travelling on underground trains etc.
The Java application here will look at a connection request's IP address and from there return a latitude and longitude plus name for that location. Thereby enabling mobile devcies who cannot lock a GPS satellite location to know where they are.
It requires the IP address to be forwarded to it by the web server, in the running case Nginx.
This protocol has been submitted to the Internet task force and will hopefully become a standard.
Rob Brew (firstname.lastname@example.org).