Filter out some altitude values. For example, negative altitudes are almost certainly wrong. When I see negative values, it’s usually -1000 feet. I also suggest filtering out ground indicator if speed is greater than, say, 200 knots. When I see this happen, the ground indicator usually is alternating between set and not set. I’m sure there are other common-sense consistency items that could be implemented. These just spring out at me when I watch the map, showing up as plane icons that alternate colors or that bounce around in the table.
This is not true, it’s fairly common to have negative altitudes for aircraft on the ground (or close to it) as ADS-B and Mode S report pressure altitude not AGL.
When I see negative values, it’s usually -1000 feet. I also suggest filtering out ground indicator if speed is greater than, say, 200 knots. When I see this happen, the ground indicator usually is alternating between set and not set. I’m sure there are other common-sense consistency items that could be implemented. These just spring out at me when I watch the map, showing up as plane icons that alternate colors or that bounce around in the table.
The general philosophy here is to locally show you exactly what is received. FA does much of the sort of filtering that you suggest before consuming the data for flight tracking purposes. But I don’t want to do that on the local map because (a) you need to have a history of data that dump1090 does not currently maintain and (b) the rules are very subjective; what’s OK for one person is bad for another. Erring on the side of caution is a good plan if you’re doing ATC but not so good if you want to see interesting things that don’t match the model you built.
Air/ground in particular is hard to get right because the parameters depend a lot on the aircraft type (and, in fact, these sorts of parameters are set per transponder). An A380 at 70kt is on the ground; a C172 at 70kt is in the air… Plus you really need radar altimeter data to do that heuristic properly. Annex 10 vol IV discusses some of the issues here.
Note that 3.1.0 (you didn’t say what version you were running) has, in particular, better air/ground detection so that it will prefer the more reliable message types over the less reliable ones, which should help a bit with the air/ground toggling if it is due to the less reliable messages squashing the more reliable ones. That said, I have seen aircraft just transmit the wrong air/ground state entirely, in both directions, so YMMV.
It would be nice if we could input the local altimeter setting (ie barometric pressure) so that the correct aircraft altitude AMSL (above mean sea level) would be displayed.
I believe air traffic controllers do this to ensure legal separation of aircraft.
Can we have a toggle button on the pop-up data box in v3.1.0, which hides the box but keeps the track of the selected plane visible? The box provides good information, but is rather large, hides a lot of screenspace, and doesn’t need to be visible all the time while you are following the progress of a flight over a long period.
I’d also like to be able to make one or more selected tracks “sticky” so that I can follow more than one flight at a time without needing to have “all tracks” enabled (I’m quite new to Piaware, so I’m sorry if this has been asked for in the past - it does seem to be rather an obvious “nice to have” feature).
Thanks for the suggestions. We’ll consider them for future updates to the map interface.