Aircraft overflight: data and method
The Aircraft overflight page in LayeredGeo property reports, and the observed flight-path figures on LayeredGeo suburb pages, contain information from adsb.lol, which is made available under the Open Database License (ODbL). adsb.lol is a volunteer network of ADS-B receivers.
What we do with it
Aircraft positions are sampled from the adsb.lol API for tiles covering Australia's populated areas, roughly once a minute, day and night. Each position is stored with an identifier that is re-salted every day, and no callsign, registration or aircraft type is kept, so nothing we hold or publish can identify or follow an individual aircraft. Positions are aggregated into cells of about 500 m by altitude band and by day or night, and each cell carries how many distinct aircraft-days were observed, a crossing-rate estimate with its uncertainty, and explicit "insufficient evidence" states where the sample cannot support a number. The report describes a pattern of traffic over a place, never a flight.
Obtaining the method
ODbL section 4.6 requires that anyone who receives a work derived from the database be offered the method used to derive it. The method is the set of scripts that run in production: the sampler, the track builder, the cell and rate builder, and the route-shape builder. We supply them, free of charge, to anyone who asks: email hello@layeredgeo.com.au with the subject "Aircraft overflight method" and we will send the current versions.
The derivative database the scripts produce is offered under ODbL v1.0 on the same request; the raw sampled positions are used internally only.