import matplotlib.pyplot as plt
from matplotlib.transforms import blended_transform_factory
from obspy import read, Stream
from obspy.geodetics import gps2dist_azimuth


host = 'http://examples.obspy.org/'
# Files (fmt: SAC)
files = ['TOK.2011.328.21.10.54.OKR01.HHN.inv',
         'TOK.2011.328.21.10.54.OKR02.HHN.inv',
         'TOK.2011.328.21.10.54.OKR03.HHN.inv',
         'TOK.2011.328.21.10.54.OKR04.HHN.inv',
         'TOK.2011.328.21.10.54.OKR05.HHN.inv',
         'TOK.2011.328.21.10.54.OKR06.HHN.inv',
         'TOK.2011.328.21.10.54.OKR07.HHN.inv',
         'TOK.2011.328.21.10.54.OKR08.HHN.inv',
         'TOK.2011.328.21.10.54.OKR09.HHN.inv',
         'TOK.2011.328.21.10.54.OKR10.HHN.inv']
# Earthquakes' epicenter
eq_lat = 35.565
eq_lon = -96.792

# Reading the waveforms
st = Stream()
for waveform in files:
    st += read(host + waveform)

# Calculating distance from SAC headers lat/lon
# (trace.stats.sac.stla and trace.stats.sac.stlo)
for tr in st:
    tr.stats.distance = gps2dist_azimuth(tr.stats.sac.stla, tr.stats.sac.stlo,
                                         eq_lat, eq_lon)[0]
    # Setting Network name for plot title
    tr.stats.network = 'TOK'

st.filter('bandpass', freqmin=0.1, freqmax=10)

# Do the section plot..
# If no customization is done after the section plot command, figure
# initialization can be left out and also option ".., show=False, fig=fig)" can
# be omitted, and figure is shown automatically
fig = plt.figure()
st.plot(type='section', plot_dx=20e3, recordlength=100,
        time_down=True, linewidth=.25, grid_linewidth=.25, show=False, fig=fig)

# Plot customization: Add station labels to offset axis
ax = fig.axes[0]
transform = blended_transform_factory(ax.transData, ax.transAxes)
for tr in st:
    ax.text(tr.stats.distance / 1e3, 1.0, tr.stats.station, rotation=270,
            va="bottom", ha="center", transform=transform, zorder=10)
plt.show()
