# http://pyrocko.org - GPLv3
#
# The Pyrocko Developers, 21st Century
# ---|P------/S----------~Lg----------
from __future__ import absolute_import
import calendar
import logging
import numpy as num
from scipy import signal
from pyrocko import util, trace
unpack_fixed = util.unpack_fixed
logger = logging.getLogger('pyrocko.io.seisan_response')
d2r = num.pi/180.
[docs]class SeisanResponseFileError(Exception):
pass
class SeisanResponseFile(object):
def __init__(self):
pass
def read(self, filename):
f = open(filename, 'rb')
line = f.readline()
line = str(line.decode('ascii'))
station, component, century, deltayear, doy, month, day, hr, mi, sec \
= unpack_fixed(
'a5,a4,@1,i2,x1,i3,x1,i2,x1,i2,x1,i2,x1,i2,x1,f6',
line[0:35],
lambda s: {' ': 1900, '0': 1900, '1': 2000}[s])
# is_accelerometer = line[6] == 'A'
latitude, longitude, elevation, filetype, cf_flag = \
unpack_fixed(
'f8?,x1,f9?,x1,f5?,x2,@1,a1',
line[50:80],
lambda s: {
' ': 'gains-and-filters',
't': 'tabulated',
'p': 'poles-and-zeros'}[s.lower()])
line = f.readline()
line = str(line.decode('ascii'))
comment = line.strip()
tmin = util.to_time_float(calendar.timegm(
(century+deltayear, 1, doy, hr, mi, int(sec)))) + sec-int(sec)
if filetype == 'gains-and-filters':
line = f.readline()
line = str(line.decode('ascii'))
period, damping, sensor_sensitivity, amplifier_gain, \
digitizer_gain, gain_1hz, filter1_corner, filter1_order, \
filter2_corner, filter2_order = unpack_fixed(
'f8,f8,f8,f8,f8,f8,f8,f8,f8,f8',
line)
filter_defs = [
filter1_corner,
filter1_order,
filter2_corner,
filter2_order]
line = f.readline()
line = str(line.decode('ascii'))
filter_defs.extend(
unpack_fixed('f8,f8,f8,f8,f8,f8,f8,f8,f8,f8', line))
filters = []
for order, corner in zip(filter_defs[1::2], filter_defs[0::2]):
if order != 0.0:
filters.append((order, corner))
if filetype in ('gains-and-filters', 'tabulated'):
data = ([], [], [])
for iy in range(3):
for ix in range(3):
line = f.readline()
line = str(line.decode('ascii'))
data[ix].extend(unpack_fixed(
'f8,f8,f8,f8,f8,f8,f8,f8,f8,f8', line))
response_table = num.array(data, dtype=num.float)
if filetype == 'poles-and-zeros':
assert False, 'poles-and-zeros file type not implemented yet ' \
'for seisan response file format'
f.close()
if num.all(num.abs(response_table[2]) <= num.pi):
logger.warning(
'assuming tabulated phases are given in radians instead of '
'degrees')
cresp = response_table[1] * (
num.cos(response_table[2])
+ 1.0j*num.sin(response_table[2]))
else:
cresp = response_table[1] * (
num.cos(response_table[2]*d2r)
+ 1.0j*num.sin(response_table[2]*d2r))
self.station = station
self.component = component
self.tmin = tmin
self.latitude = latitude
self.longitude = longitude
self.elevation = elevation
self.filetype = filetype
self.comment = comment
self.period = period
self.damping = damping
self.sensor_sensitivity = sensor_sensitivity
self.amplifier_gain = amplifier_gain
self.digitizer_gain = digitizer_gain
self.gain_1hz = gain_1hz
self.filters = filters
self.sampled_response = trace.SampledResponse(
response_table[0], cresp)
self._check_tabulated_response(filename=filename)
def response(self, freqs, method='from-filetype', type='displacement'):
freqs = num.asarray(freqs)
want_scalar = False
if freqs.ndim == 0:
freqs = num.array([freqs])
want_scalar = True
if method == 'from-filetype':
method = self.filetype
if method == 'gains-and-filters':
dresp = self._response_prototype_and_filters(freqs) \
/ abs(self._response_prototype_and_filters([1.0])[0]) \
* self.gain_1hz
elif method == 'tabulated':
dresp = self._response_tabulated(freqs) \
/ abs(self._response_tabulated([1.0])[0]) * self.gain_1hz
elif method == 'poles-and-zeros':
raise Exception(
'fix me! poles-and-zeros response in seisan is broken: where '
'should the "normalization" come from?')
# dresp = self._response_from_poles_and_zeros(freqs) *normalization
elif method == 'gains':
dresp = num.ones(freqs.size) * self.gain_total() * 1.0j * 2. \
* num.pi * freqs
else:
assert False, 'invalid response method specified'
if type == 'velocity':
dresp /= 1.0j * 2. * num.pi * freqs
if want_scalar:
return dresp[0]
else:
return dresp
def gain_total(self):
return self.sensor_sensitivity * 10.**(self.amplifier_gain/20.) \
* self.digitizer_gain
def _prototype_response_velocity(self, s):
omega0 = 2. * num.pi / self.period
return s**2/(omega0**2 + s**2 + 2.0*s*omega0*self.damping)
def _response_prototype_and_filters(self, freqs):
freqs = num.asarray(freqs, dtype=num.float)
iomega = 1.0j * 2. * num.pi * freqs
trans = iomega * self._prototype_response_velocity(iomega)
for (order, corner) in self.filters:
if order < 0. or corner < 0.:
b, a = signal.butter(
abs(order), [abs(corner)], btype='high', analog=1)
else:
b, a = signal.butter(
order, [corner], btype='low', analog=1)
trans *= signal.freqs(b, a, freqs)[1]
return trans
def _response_tabulated(self, freqs):
freqs = num.asarray(freqs, dtype=num.float)
return self.sampled_response.evaluate(freqs)
def _response_from_poles_and_zeros(self, freqs):
assert False, 'poles-and-zeros file type not implemented yet for ' \
'seisan response file format'
return None
def _check_tabulated_response(self, filename='?'):
if self.filetype == 'gains-and-filters':
freqs = self.sampled_response.frequencies()
trans_gaf = self.response(freqs, method='gains-and-filters')
atrans_gaf = num.abs(trans_gaf)
trans_tab = self.response(freqs, method='tabulated')
atrans_tab = num.abs(trans_tab)
if num.any(num.abs(atrans_gaf-atrans_tab)
/ num.abs(atrans_gaf+atrans_tab) > 1./100.):
logger.warning(
'inconsistent amplitudes in tabulated response '
'(in file "%s") (max |a-b|/|a+b| is %g' % (
filename,
num.amax(num.abs(atrans_gaf-atrans_tab)
/ abs(atrans_gaf+atrans_tab))))
else:
if num.any(num.abs(trans_gaf-trans_tab)
> abs(trans_gaf+trans_tab)/100.):
logger.warning(
'inconsistent phase values in tabulated response '
'(in file "%s"' % filename)
def __str__(self):
return '''--- Seisan Response File ---
station: %s
component: %s
start time: %s
latitude: %f
longitude: %f
elevation: %f
filetype: %s
comment: %s
sensor period: %g
sensor damping: %g
sensor sensitivity: %g
amplifier gain: %g
digitizer gain: %g
gain at 1 Hz: %g
filters: %s
''' % (self.station, self.component, util.time_to_str(self.tmin),
self.latitude, self.longitude, self.elevation, self.filetype,
self.comment, self.period, self.damping, self.sensor_sensitivity,
self.amplifier_gain, self.digitizer_gain, self.gain_1hz,
self.filters)
def plot_amplitudes(self, filename_pdf, type='displacement'):
from pyrocko.plot import gmtpy
p = gmtpy.LogLogPlot()
f = self.sampled_response.frequencies()
atab = num.abs(self.response(f, method='tabulated', type=type))
acom = num.abs(self.response(f, method='gains-and-filters', type=type))
aconst = num.abs(self.response(f, method='gains', type=type))
p.plot((f, atab), '-W2p,red')
p.plot((f, acom), '-W1p,blue')
p.plot((f, aconst), '-W1p,green')
p.save(filename_pdf)
def plot_phases(self, filename_pdf, type='displacement'):
from pyrocko.plot import gmtpy
p = gmtpy.LogLinPlot()
f = self.sampled_response.frequencies()
atab = num.unwrap(num.angle(self.response(
f, method='tabulated', type=type))) / d2r
acom = num.unwrap(num.angle(self.response(
f, method='gains-and-filters', type=type))) / d2r
aconst = num.unwrap(num.angle(self.response(
f, method='gains', type=type))) / d2r
p.plot((f, atab), '-W2p,red')
p.plot((f, acom), '-W1p,blue')
p.plot((f, aconst), '-W1p,green')
p.save(filename_pdf)
