One of the benefits of collecting several years worth of environmental data is we can look at different time frames to see how things change over time. We call these Snapshots, and they are very useful in places like Japan where the radiation levels have changed and are expected to continue changing over the coming years. We’ve added Snapshots as a new feature on the web map to better visualize historical Safecast data.
Similar to the “Historical Imagery” feature in Google Earth, snapshots show data for a specific period of time. (6 months)
To use snapshots:
1. From map.safecast.org – Click the layers selection control in the upper left hand corner of the map.
2. From the drop down menu, select “Safecast Snapshots…”
3. A time slider control will now appear, indicating the date range you are viewing.
4. To view a different snapshot, click or drag the slider in the snapshots window.
5. To close the snapshots window, choose a different layer in the layers selection control.
A few notes – If you look at an area where the levels aren’t changing much, you won’t see a difference over time. “Safecast 2013-04-15” and “Safecast 2014-03-11” are two non-snapshot layers which also provide historical data. These layers do not show a 6-month period of time. Rather, they show data from 2011-03-11 to the date indicated.So “Safecast 2014-03-11” shows data from 2011-03-11 to 2014-03-11 and “Safecast 2013-04-15” shows data from 2011-03-11 to 2013-04-15.
We’re very excited to make this feature live for everyone to play with and hope you find it as interesting as we do.