def get_mag_from_obs(obs):
"""Convert a stream to magnetic coordinate system.
Parameters
----------
obs : obspy.core.Stream
stream containing observatory components H, D or E, Z, and F.
Returns
-------
obspy.core.Stream
new stream object containing magnetic components H, D, Z, and F.
"""
h = obs.select(channel='H')[0]
e = __get_obs_e_from_obs(obs)
z = obs.select(channel='Z')[0]
f = obs.select(channel='F')[0]
obs_h = h.data
obs_e = e.data
d0 = ChannelConverter.get_radians_from_minutes(
numpy.float64(e.stats.declination_base) / 10)
(mag_h, mag_d) = ChannelConverter.get_mag_from_obs(obs_h, obs_e, d0)
return obspy.core.Stream(
(__get_trace('H', h.stats, mag_h), __get_trace('D', e.stats,
mag_d), z, f))
def get_mag_from_obs(obs):
"""Convert a stream to magnetic coordinate system.
Parameters
----------
obs : obspy.core.Stream
stream containing observatory components H, D or E, Z, and F.
Returns
-------
obspy.core.Stream
new stream object containing magnetic components H, D, Z, and F.
"""
h = obs.select(channel='H')[0]
e = __get_obs_e_from_obs(obs)
z = obs.select(channel='Z')[0]
f = obs.select(channel='F')[0]
obs_h = h.data
obs_e = e.data
d0 = ChannelConverter.get_radians_from_minutes(
numpy.float64(e.stats.declination_base) / 10)
(mag_h, mag_d) = ChannelConverter.get_mag_from_obs(obs_h, obs_e, d0)
return obspy.core.Stream((
__get_trace('H', h.stats, mag_h),
__get_trace('D', e.stats, mag_d),
z, f))
def test_get_mag_from_obs(self):
"""geomag.ChannelConverterTest.test_get_geo_y_from_obs()
``h``, ``e`` are the primary and secondary axis of the ``H``
vector in the horizontal plane of the magnetic field. ``d0``
is the declination baseline of the observatory frame of reference.
``D`` comes from the combination of ``d0`` and the angle produced
from the ``h`` and ``e`` components.
"""
# Call get_mag_from_obs using h,d of cos(30), sin(30) and
# d0 of 15 degrees. Expect H,D to equal 1, 45.
h = cos(30 * D2R)
e = sin(30 * D2R)
d0 = 15 * D2R
H, D = channel.get_mag_from_obs(h, e, d0)
assert_almost_equal(H, 1, 8, 'Expect H to be 1.', True)
assert_almost_equal(D, 45 * D2R, 8, 'Expect D to be 45.', True)