Since the Great East Japan Earthquake and the following Fukushima disaster, there have been quite some maps of nuclear radiation sensor data out there (for those interested, in my sketchpad, I noted down: the just posted and beautiful 311 Scale map, the NYTimes version, a radiation data-specific 3D globe and some others).
But what would be possible if nuclear radiation data of a lot of sensors is aggregated and visualized over time? Marian Steinbach tried such this, and created this amazing video of the measurements taken by over 1750 Geiger counters currently present in Germany.
First, the animation clearly shows how gamma radiation behaves dynamically when seen over a scale of a country: radiation changes by location as well as over time. The probable reason behind the wave-like motions moving over the country is the influence of rain, which tend to increase the readings. (A claim which could be checked by layering actual rain measurements on top of the radiation data)
Secondly, it demonstrates that as long as governments come up with visualizations like these (if they come up with one at all), there is still an urgent need to open up this data for others to try to do better.