Mozilla has launched a highly experimental Firefox browser plug-in featuring powerful geo-location capability. Called Geode, the technology allows the location of web surfers to be fixed and then maintained as users move about their hometowns, across the nation, or even when travelling around the world.

“You’ll be able to play with this in the upcoming beta releases of Firefox 3.1,” Geode’s developers said. “We realized, though, that some of our Firefox 3 users might also want to get a head start playing with geo-location today, and users can tell us what they think of the experience it provides.”

Among other things Geode gives websites the native ability to request access to the approximate position of the user’s computer. This enables search results to be ranked according to the user’s proximity to shops, restaurants, theatre’s, parks and local attractions.

Mozilla think that Geode can offer more. “Imagine a news site whose local section is, in fact, actually local, or Web site authentication that only allows you to log in from certain physical locations, like your house,” Geode’s developers said.

Geode’s enabling API, which is based on the W3C geo-location spec, defines a high level interface to location information associated with a hosting device. In addition to accessing standard GPS signals, the technology also will be able to approximate the user’s location based on any available network signals, including Bluetooth and IP addresses.

Mozilla is using Skyhook’s Loki technology to map locally available Wi-Fi signals to the user’s location. This allows Geode to almost instantly get a location fix with an accuracy of between 10 to 20 metres, regardless of whether the user is indoors or outside. By contrast, standard GPS-based methods can take more than 45 seconds to determining a locations latitude and longitude.

Geode allows users who are on holiday, for example, to take pictures and write short notes at various locations in the city, and use a web application to automatically tag each content item with the correct location data. The web app would then automatically upload the tourist’s content to a social-networking site.

Mozilla notes that Geode users will be able to control just how much information they are willing to provide about their current location.

“With Geode, when a Web site requests your location, a notification bar will ask how much information you want to give that site — your exact location, your neighborhood, your city, or nothing at all,” developers said.