Thermal properties

[iamambrus]

Hi Marcin, looks very promising. To be truly useful though the following information would be necessary:

• thermal entry height
• thermal exit height
• (average) thermal strength
• time spent in thermal (can be calculated from current data, still nice)
• optionally some wind/drift information

Maybe this is all doable with your library, if so please could you provide some instructions? Thanks.

[marcin-osowski]

Hi,

the first 4 things on the list are there in the library. After you parse an IGC flight and get a Thermal object you can query it like this:

ipdb> flight
<igc_lib.Flight instance at 0x1011336c8>
ipdb> flight.thermals[0]
Thermal(vertical_velocity=1.61 m/s, duration=7m 8s)
ipdb> flight.thermals[0].enter_fix.alt
537.0
ipdb> flight.thermals[0].exit_fix.alt
1224.0
ipdb> flight.thermals[0].vertical_velocity()
1.605140186915888
ipdb> flight.thermals[0].time_change()
428.0

See the Flight::create_from_file() function on how to create a Flight object, and the Thermal class in igc_lib.py.

As far as wind/drift calculation goes, it's not currently there, but a basic version: (exit_position - entry_position)/(exit_time - entry_time) should be pretty easy to implement. Let me know if you'd need that, I can have a look into it. Also, I'm happy to accept pull requests here :)

[iamambrus]

Great, thank you! Looked through the code and it's very readable. Will look into the wind drift topic, shouldn't be that hard to implement.

[marcin-osowski]

Sure, if you get some time for it and get it working I'll be happy to review a pull request with an extra feature - sounds useful to have.