The folks at +OpenSignal may not realize the importance their service is to +Hamradio folks. The site uses crowd-sourced data from people's cellular devices to portray the Radio Frequency, including WiFi.
The Open Signal Map shows which of the carriers are being used in an area. The legend is for weak signal, strong signal, and no data collected.
The application on the smart phone also includes a speed test so the operator can determine the quality of the network, including the wifi network currently connected.
With more and more amateur radio operators moving to Digital Mobile Radio, DSTAR, +Echolink and Internet Radio Linking Project, especially mobile, it may be important to plan use during travel periods.
Are you using any of the linked systems over wifi or cellular networks?
