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das-developers / das2java

The original das2 library. Provides interactive publication-ready 2-D plotting
https://das2.org
GNU Lesser General Public License v3.0
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spectrogram cadence breaks in Y #38

Closed jbfaden closed 1 year ago

jbfaden commented 1 year ago

Over the years I've noticed where there are breaks in a spectrogram at low frequencies, often when looking at the result of fftPower in Autoplot. Corentin pointed this out with his spectrogram, too. This is a bit of his spectogram:

image

A review of the guess cadence routine needs to be done.

jbfaden commented 1 year ago

See also https://github.com/das-developers/das2java/issues/15

jbfaden commented 1 year ago

Here is where slices of Juno vap+das2server:https://jupiter.physics.uiowa.edu/das/server?dataset=Juno/WAV/Survey&start_time=2021-07-21T06:00:00.000Z&end_time=2021-07-21T08:00:00.000Z show breaks:

image

Here is the data: cadenceCheck.d2s.zip

jbfaden commented 1 year ago

See also https://github.com/das-developers/das2java/issues/41

jbfaden commented 1 year ago

See also https://sourceforge.net/p/autoplot/bugs/1582/

jbfaden commented 1 year ago

There's a branch which kicks in for small log sequences, looking for those are the ytags of a spectrogram. I've tweaked the logic so that these sequences can be longer (160 elements, LIMIT_YTAGS_LENGTH_CHECK) and verified this does not break other tests.