I totally dig this Sony GPS designed to integrate smoothly with Sony digicams so that photos can be geotagged by comparing the time on the GPS recording with the time stored on images by the camera.
Using time as a synchronization device for location data is definitely key in Imity. Having a whole Sony toolchain for it seems overkill though. GPS devices with bluetooth are cheap and plentiful and can coordinate with the cameras on their own.

(side note: recording bluetooth transmitted GPS coordinates into your presence data is on the development roadmap for Imity - just not scheduled for the beta release coming up in a few weeks)

(via Julian Bleecker)

tagged bluetooth, gps and photos