Source code for pyrocko.io.css

# http://pyrocko.org - GPLv3
#
# The Pyrocko Developers, 21st Century
# ---|P------/S----------~Lg----------
from __future__ import absolute_import
import os
import numpy as num
import logging
from struct import unpack
from pyrocko import trace, util

logger = logging.getLogger('pyrocko.io.css')


'''
See http://nappe.wustl.edu/antelope/css-formats/wfdisc.htm for file format
reference.
'''

storage_types = {
        's4': ('>%ii'),
        'i4': ('<%ii'),
}

template = [
    ('sta', str, (0, 6), 'station code'),
    ('chan', str, (7, 15), 'channel code'),
    ('time', float, (16, 33), 'epoch time of first sample in file'),
    ('wfid', int, (34, 43), 'waveform identifier'),
    ('chanid', int, (44, 52), 'channel identifier'),
    ('jdate', int, (53, 61), 'julian date'),
    ('endtime', float, (62, 79),  'time +(nsamp -1 )/samles'),
    ('nsamp', int, (80, 88), 'number of samples'),
    ('samprate', float, (89, 100), 'sampling rate in samples/sec'),
    ('calib', float, (101, 117), 'nominal calibration'),
    ('calper', float, (118, 134), 'nominal calibration period'),
    ('instype', str, (135, 141), 'instrument code'),
    ('segtype', str, (142, 143), 'indexing method'),
    ('datatype', str, (144, 146), 'numeric storage'),
    ('clip', str, (147, 148), 'clipped flag'),
    ('dir', str, (149, 213), 'directory'),
    ('dfile', str, (214, 246), 'data file'),
    ('foff', int, (247, 257), 'byte offset of data segment within file'),
    ('commid', int, (258, 267), 'comment identifier'),
    ('Iddate', util.stt, (268, 287), 'load date')
]


[docs]class CSSWfError(Exception): def __init__(self, **kwargs): f2str = { str: 'string', int: 'integer', float: 'float', util.stt: 'time' } kwargs['convert'] = f2str[kwargs['convert']] error_str = 'Successfully parsed this:\n' for k, v in kwargs['d'].items(): error_str += '%s: %s\n' % (k, v) error_str += '\nFailed to parse the marked section:' istart = kwargs['istart'] istop = kwargs['istop'] npad = 12 error_mark = ' ' * npad error_mark += '^' * (istop - istart) error_str += '\n%s\n%s\n' % (kwargs['data'][istart-npad: istop+npad], error_mark) error_str += 'Expected {desc} (format: {convert})\n'.format(**kwargs) error_str += \ 'checkout http://nappe.wustl.edu/antelope/css-formats/wfdisc.htm' Exception.__init__(self, error_str) self.error_arguments = kwargs
[docs]class CSSHeaderFile(object): ''' CSS Header File :param filename: filename of css header file Note, that all binary data files to which the underlying header file points to will be loaded at once. It is therefore recommended to split header files for large data sets ''' def __init__(self, filename): self.fn = filename self.data = [] self.read()
[docs] def read_wf_file(self, fn, nbytes, dtype, foff=0): ''' Read binary waveform file :param fn: filename :param nbytes: number of bytes to be read :param dtype: datatype string ''' with open(fn, 'rb') as f: fmt = dtype % nbytes f.seek(foff) try: data = num.array(unpack(fmt, f.read(nbytes * 4)), dtype=num.int32) except Exception: logger.exception('Error while unpacking %s' % fn) return return data
[docs] def read(self): ''' Read header file. ''' with open(self.fn, 'rb') as f: lines = f.readlines() for iline, line in enumerate(lines): line = str(line.decode('ascii')) d = {} for (ident, convert, (istart, istop), desc) in template: try: d[ident] = convert(line[istart: istop].strip()) except Exception: raise CSSWfError(iline=iline+1, data=line, ident=ident, convert=convert, istart=istart+1, istop=istop+1, desc=desc, d=d) fn = os.path.join(self.superdir, d['dir'], d['dfile']) if os.path.isfile(fn): self.data.append(d) else: logger.error( 'no such file: %s (see header file: %s, line %s)' % ( fn, self.fn, iline+1))
@property def superdir(self): return os.path.dirname(self.fn) def iter_pyrocko_traces(self, load_data=True): for idata, d in enumerate(self.data): fn = os.path.join(d['dir'], d['dfile']) logger.debug('converting %s', d['dfile']) try: if load_data: ydata = self.read_wf_file( os.path.join(self.superdir, fn), d['nsamp'], storage_types[d['datatype']], d['foff']) else: ydata = None except IOError as e: if e.errno == 2: logger.debug(e) continue else: raise e dt = 1./d['samprate'] yield trace.Trace(station=d['sta'], channel=d['chan'], deltat=dt, tmin=d['time'], tmax=d['time'] + d['nsamp']/d['samprate'], ydata=ydata)
[docs]def iload(file_name, load_data, **kwargs): ''' Iteratively load traces from file. :param file_name: css header file name :param load_data: whether or not to load binary data ''' wfdisc = CSSHeaderFile(file_name) for pyrocko_trace in wfdisc.iter_pyrocko_traces(load_data=load_data): yield pyrocko_trace