Producing Radiation Maps - Participatory Mapping: New Data, New Cartography - page 107

naturally assume the worst. 35 Akiba ,

blog

Freakslab , March 24, 2011

Increasing the number of sources not only makes a more
comprehensive map but it also facilitates verification of the
government data. Combining several data sources also helps
avoiding the disadvantages of Geiger counter measurements.
Watchfulness for discrepancies from any given data source is
supposed to increase as different sources are constantly
aggregated. This is confirmed by the owner of a Geiger
counter whose data contributed to Haiyan Zhang's map
(Table 4.1, see map no. 3). The concentration of water in the
sensor caused a short-circuit, which made the values for
central Tokyo soar to near-Fukushima numbers. Following
the panicked reactions of some Web users in the comment
section of the map, the owner of the Geiger counter insisted
on the need to cross-check sources rather than concentrating
on any single one:

To a point I feel responsible for the nervous
reactions online to this bad data, and to that
extent I am very sorry for causing unnecessary
concern. To be clear though: I have publicly
retracted the data in a number of places online
and adequately explained the reason for the error
- if people continue to attribute any value to this
data they validate the complaints of TEPCO and
the govt about citizen monitoring and its
reliability. An assumption of any automated
monitoring is that the sensor must always be
regarded as not implicitly 100% trustworthy - so
we check when the readings are surprising; the
reason we do crowdsourced data is because many
data points protect us from the overvaluing one

35 See: http://freaklabs.org/index.php/Blog/Misc/Hacking-a-Geiger-Counter-
in-Nuclear-Tokyo.html.