Question about calculations in Stats

FlightAware ADS-B Flight Tracking
1

If i am comparing the hourly received number of positions and aircraft and compare it to the values in the table regarding reported aircraft and reported positions i can see a large deviation.

I understand that the reported data to FA can differ from the received values, but is there a calulation algorithm on how this is done?

Thanks

2

What are you comparing, exactly?

3

Morning

i am comparing values of these three graphics containing the values.
The hourly chart with the blue boxes per hour are reporting higher values than the two above, so i assume not all of these are counted into the tables.

The screenshot was taken this morning
Values in the graphics vs values in the tables:
Positions: 12263 vs. 12356 (the deviation is larger at the end of the day)
Aircraft: 342 vs. 179 (also larger at the end of the day)

Also the title “hourly collection” is not clear to me. What is collected?

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4

Not sure where you are getting 12263 positions from, can you explain?

For the aircraft I guess that you are summing the hourly aircraft counts and comparing it to the daily count? You can’t expect those to match; the counts are “unique aircraft seen in the time window” and it is common for an aircraft to appear in more than one hourly time window during a day.

5

Thanks

for the aircraft i like the explanation.

The question regarding the positions are counted from the hourly distribution. I will check it later today again if there’s a deviation.

How is it counted if an aircraft shows up twice over the day because of two different flights? Is this then counted as unique because of the registration or twice because of the flight?

6

Unique per aircraft / airframe.

7

Thanks, now it makes sense :+1:t4:

8

So you are summing the hourly position numbers? I would expect the sum across the UTC day to match the daily numbers, so long as

  1. you are looking at a range of hours that matches the UTC day boundaries; and
  2. you look at the data some time after the day has completed (during the day, the hourly and daily totals might be out of sync because they’re not necessarily updated at the same point in time)
9

Thanks for the explanation. It was just out of curiosity.

10

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