Respect method='full' for Stream.plot(type='section')

[liamtoney]

What does this PR do?

For section-type plots: Ensures that the full Trace is plotted when a user requests it to be (i.e., when specifying method='full'). Parallels the logic implemented in the WaveformPlotting.plot() method.

Why was it initiated? Any relevant Issues?

Fixes #3375.

PR Checklist

• Correct base branch selected? master for new features, maintenance_... for bug fixes
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[liamtoney]

Demo:

from obspy import read
import matplotlib.pyplot as plt
import numpy as np

# Read in example data
st = read()

# Pretend that the three components are actually traces
# from different stations at 10, 20, 30 km from source
for tr, distance in zip(st, [10 * 1000, 20 * 1000, 30 * 1000]):
    tr.stats.distance = distance  # [m]

# Artifically increase the number of points in each trace to exceed max_npts
# (this makes the resampling for 'fast' clear)
for tr in st:
    tr.data = np.tile(tr.data, 20)

# Plot record section
fig = plt.figure()
st.plot(fig=fig, type='section', orientation='horizontal', method='fast', alpha=1, color='red')
st.plot(fig=fig, type='section', orientation='horizontal', method='full', alpha=1)
fig.axes[0].set_xlim(5, 10)  # Zoom in to show effect of the different plotting methods
fig.show()

[filefolder]

seems like a nice fix! i think you may have to rebase to the current maintenance branch though

[liamtoney]

seems like a nice fix! i think you may have to rebase to the current maintenance branch though

Sorry, I don't understand. The current maintenance branch is maintenance_1.4.x, no?

[filefolder]

seems like a nice fix! i think you may have to rebase to the current maintenance branch though

Sorry, I don't understand. The current maintenance branch is maintenance_1.4.x, no?

ahh you're right sorry! i have lost track of the passage of time between versions.

[liamtoney]

Hi folks, just checking if there is more feedback on this PR. Thanks.

[filefolder]

looks good to me and tested fine on my machine

[liamtoney]

looks good to me and tested fine on my machine

Great! Looks like this is ready to be merged, then? I can't do that part :)

[megies]

sorry for the delay @liamtoney.. looks good to me, just two comments:

1. would be nice to have a minimal regression test, easy to do with just a few lines using e.g. np.random.random_integers(-100, 100, 10010) as a single Trace's data and then plotting it and checking the resulting Line object, something like assert len(ax.lines[0].get_xdata()) == 10010 (to make sure point number is not reduced to max_npts.

2. I was wondering why the min-max plot was looking that off from the original data.. turns out it's doing something different completely from the min-max routine on normal wiggle plot. I think it might be good to refactor the _plot_min_max routine a little bit to factor out the calculation routine for x/y values and then use the same routine in the section plot.

Would be nice to still get 1. in here, but 2. could be something for a different PR / another time.

[liamtoney]

2. I was wondering why the min-max plot was looking that off from the original data.. turns out it's doing something different completely from the min-max routine on normal wiggle plot. I think it might be good to refactor the _plot_min_max routine a little bit to factor out the calculation routine for x/y values and then use the same routine in the section plot.

Are you referring to the fact that the section plot resamples the data while the standard plot does the min/max? Maybe a separate PR for that?

[liamtoney]

1. would be nice to have a minimal regression test, easy to do with just a few lines using e.g. np.random.random_integers(-100, 100, 10010) as a single Trace's data and then plotting it and checking the resulting Line object, something like assert len(ax.lines[0].get_xdata()) == 10010 (to make sure point number is not reduced to max_npts.

Nice test idea! I implemented that and am ready for re-review, I think.

[megies]

Are you referring to the fact that the section plot resamples the data while the standard plot does the min/max? Maybe a separate PR for that?

Yes, I was assuming it was doing the same min-max thing we have for the regular wiggle plot and was confused why the line was overshooting in some points and stuff. And yes, definitely something for another time, if at all. It's not a big deal really.

[megies]

Thanks for the fix! 🚀