Mostly a nitpick, but pressure sensors don't give a good measure of absolute altitude ever, regardless of the number of samples. You must calibrate it using pressure measurements from a ground station nearby in space and time, or else it tells you roughly nothing.
Weather matters a lot, as you say. The variation caused by weather can be equivalent to several thousand feet of altitude. Worse, changes due to weather are long-term. You can't filter them out, period. Samples taken four minutes apart can tell you changes in altitude, since the weather won't change that much in such a short time, but there's no way to backtrack to absolute altitude without calibration, no matter how many samples you take.
True. However if we're looking for very brief landings followed by periods of flight you might see that in the pressure data.
You'd expect some flat "flight level" pressure over a day, with V pressure changes to correlate with landings (or swoops in mid-air). You would need to correlate these with other sensors for it to mean anything concrete but it could corroborate or disprove other theories.
Right, but you couldn't distinguish a V that was a brief landing from a V that was a dive and climb, nor could you distinguish a flat line that was cruising from a flat line that was sitting on the ground.
I don't doubt that pressure data would be useful, it just doesn't give you altitude data.
Weather matters a lot, as you say. The variation caused by weather can be equivalent to several thousand feet of altitude. Worse, changes due to weather are long-term. You can't filter them out, period. Samples taken four minutes apart can tell you changes in altitude, since the weather won't change that much in such a short time, but there's no way to backtrack to absolute altitude without calibration, no matter how many samples you take.