Stats Questions


#1

Hi,

I have a few questions about the stats page.

On the Stats page in the 2 week stats table, what is “Reports Received”, is it related to (or even just another way to say) Positions Received.

The Hourly Received Reports (positions | aircraft) “block chart”, how are the numbers (per hour) for aircraft calculated. If I add up all 24 blocks for a day it comes to much higher than the day Aircraft Seen figure in the 2 week stats table.

Also, I have my data feeding a local copy of Virtual Radar Server, if I do a report on what I saw yesterday it shows about 7000 entries, so over double what FlightAware shows, I assume some of the difference is because FlightAware aren’t interested (don’t count) certain flights such as helicopter, military, small (light aircraft), however it’s still quite a big difference.

Thanks.


#2

My understanding:

“Reports” = “Positions” = any message about an aircraft sent by piaware to flightaware

The pie/radar chart and bar chart are ADS-B positions only. The hourly block chart is ADSB + MLAT + Other. “Other” positions are not really lat/lon positions, but altitude/speed/callsign/etc reports.

I think the aircraft count in the block chart shows the number of unique aircraft seen in each hour. You can’t just add them all up because the same aircraft may be counted in multiple hour blocks.

As for VRS, I believe that report shows flights not unique aircraft, so if a plane makes two trips in one day it will be counted twice.


#3

I have about a dozen Tourist helicopters, 5 or 6 RPT helicopters, 5 or 6 news helicopters and 5 or 6 Police helicopters within 10-20NM.
I can get 100,000+ position reports from them, but they still only count as about 30 aircraft.
They could be counted in 6-8 hourly reports but will not affect the total Aircraft count(once they are counted).


#4

Ok, so when I have been running the Gain testing script with Dump1090, and it summarises number of Messages, Positions & Planes would that relate to the Positions value then.

That’s what I assumed, so if a plane is in range from say 10:45 to 11:15 then it would count as one plane seen in the 10 hour block and 1 plane seen in the 11 hour block.

OK, so if I pick up the same plane twice (say arriving at and then leaving an airport) it’s only counted as 1 Plane in the total daily count. Assume that’s why my plane count seems to go up slower nearer the end of the day (because they may have already been counted that day).

Thanks.


#5

For the gaintest script:
messages = all messages processed by dump1090 (mode-s, ads-b, whatever)
positions = ads-b messages with lat/lon
aircraft = number of unique ICAO hex codes

Piaware doesn’t forward every dump1090 message, it only sends reports to FA every few seconds for each aircraft depending on how much its altitude or speed or position etc changes. So if dump1090 gets 500 messages your FA stats page might only show 10 reports for example.

(of course i’m just a user so if this is wrong hopefully FA staff will correct me :slight_smile:)