I built a backend in Kotlin to query the ThingSpeak API and find all available public channels. This rendered 199,238 channels.
After searching for channels which contained "weather" in the description or name I was able to find 1554 channels, out of those only 569 were active and had GPS coordinates in the last 7 days.
I then built a ReactJS front end with Google Maps to map these on the globe.
The app is pretty cool and uses my Channel Grapher app to load the data.