A very relevant map that shows the diversity of location-sensing technologies.

"Each box’s horizontal span shows the range of accuracies the technology covers; the bottom boundary represents current deployment, while the top boundary shows predicted deployment over the next several years"

Taken from Hazas, M., Scott, J., and Krumm, J. Location-aware computing comes of age. IEEE Computer 37, 2 (2004), 95–97

Why do I blog this? some good material for a paper I am writing about location-awareness.