Radiation Maps woohoo!
How accurate this information is,
and what the best use for them are,
is beyond me.
A recently published map of cesium 134 and 137 distribution and concentration,
from the Ministry of Education, Culture, Sports, Science and Technology,
based on measurements from a helicopter.
Light yellow: 30,000 ~ 60,000 Becquerel(Bq) per square meter (m2)
Darker yellow: 60,000 ~ 600,000 Bq/m2
Orange: over 600,000 Bq/m2
A radiation contour map by Yukio Hayakawa from Gunma University.
His blog states that he is a soil scientist who studies volcanic ash fall.
I'm not sure what data this is based on,
but it represents the radioactive material that landed on March 2011.
Another map by Yukio Hayakawa depicting the movement of radioactive pollutants in March.
His blog (Japanese) http://kipuka.blog70.fc2.com/