Many of the sensors near me show a Zero for ‘Position Rating’, but I can not find any more info about what exactly determines the ‘Position Rating’. Can someone elaborate on the exact parameters used to determine this ? What factors is this based upon ?
Position rating provides a measure of how accurate the map position may be.
The position rating is calculated using Google’s Geolocation API. When a sensor connects to WiFi, it sends the IP address to Google for a location estimate. This is then compared against the latitude and longitude set during registration to determine the star rating.
If the sensor is reconnected to a different WiFi network, then the location check will be performed again and updated.
Please note that the 7.03 and 7.04 firmware versions currently have a bug affecting geolocation for some sensors. This is not an issue with Google’s API but rather the firmware of PurpleAir sensors.
If anyone suspects that there is an error in their sensor’s location star rating, please send an email to contact@purpleair.com.