Source code for pyrocko.io.seisan_response

# 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 = 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)