def get_obs_from_mag(mag, include_d=False):
"""Convert a stream to magnetic observatory coordinate system.
Parameters
----------
stream: obspy.core.Stream
stream containing magnetic components H, D, Z, and F.
include_d: boolean
whether to also include the observatory D component
Returns
-------
obspy.core.Stream
new stream object containing observatory components H, D, E, Z, and F
"""
h = mag.select(channel='H')[0]
d = mag.select(channel='D')[0]
z = mag.select(channel='Z')[0]
f = mag.select(channel='F')[0]
mag_h = h.data
mag_d = d.data
d0 = ChannelConverter.get_radians_from_minutes(
numpy.float64(d.stats.declination_base) / 10)
(obs_h, obs_e) = ChannelConverter.get_obs_from_mag(mag_h, mag_d, d0)
traces = (__get_trace('H', h.stats,
obs_h), __get_trace('E', d.stats, obs_e), z, f)
if include_d:
obs_d = ChannelConverter.get_obs_d_from_obs(obs_h, obs_e)
traces = traces + (__get_trace('D', d.stats, obs_d), )
return obspy.core.Stream(traces)
def get_obs_from_mag(mag, include_d=False):
"""Convert a stream to magnetic observatory coordinate system.
Parameters
----------
stream: obspy.core.Stream
stream containing magnetic components H, D, Z, and F.
include_d: boolean
whether to also include the observatory D component
Returns
-------
obspy.core.Stream
new stream object containing observatory components H, D, E, Z, and F
"""
h = mag.select(channel='H')[0]
d = mag.select(channel='D')[0]
z = mag.select(channel='Z')[0]
f = mag.select(channel='F')[0]
mag_h = h.data
mag_d = d.data
d0 = ChannelConverter.get_radians_from_minutes(
numpy.float64(d.stats.declination_base) / 10)
(obs_h, obs_e) = ChannelConverter.get_obs_from_mag(mag_h, mag_d, d0)
traces = (
__get_trace('H', h.stats, obs_h),
__get_trace('E', d.stats, obs_e),
z, f)
if include_d:
obs_d = ChannelConverter.get_obs_d_from_obs(obs_h, obs_e)
traces = traces + (__get_trace('D', d.stats, obs_d),)
return obspy.core.Stream(traces)
def test_get_obs_from_mag(self):
"""geomag.ChannelConverterTest.test_get_obs_from_mag()
Call the get_obs_from_mag function, using trig identities too
test correctness, including d0. Which should test most of the d0
calls.
"""
H = 1
D = -22.5 * D2R
(h, e) = channel.get_obs_from_mag(H, D, 22.5 * D2R)
assert_almost_equal(h, cos(45 * D2R), 8,
'Expect h to be cos(45)', True)
assert_almost_equal(e, -cos(45 * D2R), 8,
'Expect e to be -cos(45).', True)
