This isn't a practical app though. If you're hoping that Architecture of Radio will guide you towards areas devoid of signals, you'll be disappointed. This is an art project, and an ambitious one at that. Not just because the combination of location services and a giant database or wireless networks requires plenty of technical skill to implement, but because any attempt to reveal the invisible is rife with challenges.

The app is on display at the ZKM Center for Art and Media Karlsruhe in Germany, but you can try it out yourself at home. It's available for $3 in the App Store for users of iOS 9. Android customers will have to hold out until early 2016 for their own version.

[Image credit: Juuke Schoorl]