plot_waveforms.py

#!/usr/bin/env python3
"""Render miniSEED waveforms to a PNG (one panel per channel)."""
import argparse
from datetime import datetime, timezone

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
from obspy import read, UTCDateTime


def plot(infile, outfile, origin=None):
    st = read(infile)
    st.merge(method=1)  # stitch contiguous records, fill gaps with masked arrays
    st.sort(["channel"])

    n = len(st)
    fig, axes = plt.subplots(n, 1, figsize=(12, 2.2 * n + 1), sharex=True)
    if n == 1:
        axes = [axes]

    origin_utc = None
    if origin is not None:
        origin_utc = UTCDateTime(origin if isinstance(origin, str)
                                 else origin.astimezone(timezone.utc).replace(tzinfo=None).isoformat())

    for ax, tr in zip(axes, st):
        times = [(tr.stats.starttime + t).datetime for t in
                 (tr.times())]
        ax.plot(times, tr.data, lw=0.6, color="#1a1a1a")
        ax.set_ylabel(tr.id.split(".")[-1], rotation=0, ha="right", va="center", fontsize=11)
        ax.grid(True, alpha=0.25)
        ax.margins(x=0)
        if origin_utc is not None:
            ax.axvline(origin_utc.datetime, color="#cc2222", lw=1.0, ls="--")

    axes[-1].xaxis.set_major_formatter(mdates.DateFormatter("%H:%M:%S"))
    fig.autofmt_xdate()

    title = f"{st[0].id.rsplit('.', 1)[0]}  |  {st[0].stats.starttime.strftime('%Y-%m-%d %H:%M:%S')} UTC"
    if origin_utc is not None:
        title += f"  |  origin {origin_utc.strftime('%H:%M:%S')} UTC (red)"
    fig.suptitle(title, fontsize=12)
    fig.tight_layout(rect=[0, 0, 1, 0.98])
    fig.savefig(outfile, dpi=130)
    plt.close(fig)
    return outfile


def main():
    ap = argparse.ArgumentParser(description="Plot miniSEED waveforms to PNG")
    ap.add_argument("--input", required=True)
    ap.add_argument("--out", help="output PNG (default: alongside input)")
    ap.add_argument("--origin", help="origin time UTC to mark, e.g. 2026-06-13T17:28:12")
    args = ap.parse_args()

    st = read(args.input)
    print(st.__str__(extended=True))

    out = args.out or (args.input.rsplit(".", 1)[0] + ".png")
    plot(args.input, out, origin=args.origin)
    print(f"plot -> {out}")


if __name__ == "__main__":
    main()