Even more impressive, it can also auto-tag a location based on which cell tower your camera phone is using when you upload photos to Flickr. One advantage of this is that tower-based location works when you're indoors. The biggest disadvantage is that it works only on some phones and with some carriers. It's also possible to combine cell tower geolocation with GPS information. This points to likely approaches in future camera phones -- geotagging and location awareness using the best means available, including GPS, cell tower information and other data.

Microsoft Corp. unveiled a research project at its TechFest event this week that identifies your location using the picture itself. The idea is that thousands -- potentially millions -- of "landmarks" in a given city are indexed in a database and associated with exact coordinates. By taking a picture of one of the landmarks with your camera phone, the software sends that picture via your phone's data connection for processing. A remote mega-computer quickly identifies the building, and sends back location information to your phone about the specific location.

It's not hard to imagine a network like Flickr taking this to the next level, where individual users post millions of pictures that are geotagged, then those pictures are entered into the big database to be used in reverse for identifying the location of objects in the world through photo recognition.

A company called NXP Software has developed technology called swGPS that does in software what normally requires a chip, which it says lowers the cost, increases the speed and reduces the power demand of automatic geotagging -- perfect for tiny camera phones.

The geotagging vision