The displayed measurements can be filtered according to 4 main criteria, depending on the qualification given by the OpenRadiation community to these measurements.
- Ground level measurement: the measurement is a priori considered as representative of an environmental measurement taken at ground level (ideally outside and at 1 meter height, but measurements taken inside a building or at different heights from the ground are also part of this category)
- In-flight measurement: the measurement was taken in an aircraft (even if the aircraft is in the airport and has not yet taken off)
- Temporary source measurement : the user has measured a temporary source, i.e. a moving source (a truck transporting radioactive material, ...), or a moving point source (a radioactive object: alarm clock, stone, ...), or has passed a person who has had a nuclear medicine examination, or has measured a sporadic source (safety X-ray check, radiological examination, ...), etc.
- Wrong measurement: the measurement is declared incorrect because of a technical problem, whether intentional or not: unsuitable or defective sensor, GPS problem, or data capture or transmission problem.
For performance reasons, the map does not display all the measurements performed, but only the most recent measurements, according to the filter criteria that the user has entered.
The data that appears on the map uses the coordinates of a geolocation system. These data are more or less accurate depending on the quality of the GPS signal reception (some measurements can be located several hundred meters away). Some measurements can also be overlayed (taken at the same place but at different times). To see them it is possible to click on "Timeline" which allows to have a view according to the date of measurement and not according to geographical criteria.
If a measurement appears with a different value, it is likely it has been displayed "under" another measurement taken at the same location.
Finally, it is important to remember that geiger counters measure gamma radiation but not alpha or beta radiation and neutrons for which other measuring devices are required.