It wasn't at all clear where the data comes from, but after a little digging it looks like volunteers are driving around with homemade devices collecting data.
https://bgeigiezen.safecast.jp/store-2/
Looks like they might have had apps too, but they have been pulled from the App Store and Play Store?
Can the sensors that provide the data be trusted?
Or could anyone in control of the network inject fake sensor data?
https://safecast.org/devices/ https://safecast.org/history-of-safecast/ https://safecast.org/about/
It’s quite a wonderful set of globally-distributed volunteers brought together by varying passions - from hardware hacking to citizen science.
Whether from fixed or mobile sensors, whether from radiation or air quality sensors, all data is CC0-licensed at birth and is freely available for download.
Interesting that Three Mile Island is not any higher than background levels. I would have expected even a minor bump. I suppose 45 years is a long time.
what a misleading notation on the map. Also not clear when blue is radiation or bad air quality. Also, yellow is higher than red..
If somebody assigned you to design a map that's extremely difficult to interpret, you probably wouldn't be clever enough to come up with this.
https://ibb.co/TLDxBZF