Modify PPSD function

Users Mailing List Archive
1

Hey everyone,

is it possible (by manipulating some ObsPy script…?) to modify the PPSD function of ObsPy such that I can change the plot output? I would like to change the range of the x-axis and if possible add extra lines for e.g. drawing a line that marks NHNM - 20 dB for a certain period range.

Any idea how I could to that?

Thanks a lot and best regards,
Florian Fuchs

2

Hi Florian

Sure you can edit the source files, but this is probably not the recommended thing to do. Instead its safer to extend the PPSD class with a new plotting function that does what you want. To ease this you may want to have a look at the original code of PPSD.plot(), this you will find here: � regP

3

..or just tweak the plot with matplotlib after doing the builtin PPSD
plotting, e.g.:

import matplotlib.pyplot as plt
from obspy.signal.spectral_estimation import get_NLNM
from obspy.signal.tests.test_spectral_estimation import _get_ppsd

ppsd = _get_ppsd()
ppsd.plot(period_lim=[0.5, 10], show=False)
fig = plt.gcf()
ax = fig.axes[0]

x, y = get_NLNM()

ax.plot(x, y + 10, color="r", lw=2.5, ls="--", label="NLNM + 10db")
ax.legend()
plt.show()

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figure_1.jpg

4

Awesome,

thanks a lot!

- Florian

5

Attached are NLNM and NHNM noise models in case anyone needs them ...

-Mike

NHNM.ascii (187 Bytes)

NLNM.ascii (3.65 KB)

6

Thanks Mike, however, as indicated in the previous example they are also
included in ObsPy. No need to keep them around separately.

from obspy.signal.spectral_estimation import get_NLNM, get_NHNM
x, y = get_NLNM()

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