def writeSU(stream, filename, byteorder=None, **kwargs): # @UnusedVariable
"""
Writes a Seismic Unix (SU) file from given ObsPy Stream object.
.. warning::
This function should NOT be called directly, it registers via the
the :meth:`~obspy.core.stream.Stream.write` method of an
ObsPy :class:`~obspy.core.stream.Stream` object, call this instead.
:type stream: :class:`~obspy.core.stream.Stream`
:param stream: The ObsPy Stream object to write.
:type filename: str
:param filename: Name of file to write.
:type byteorder: ``'<'``, ``'>'``, or ``None``
:param byteorder: Determines the endianness of the file. Either ``'>'`` for
big endian or ``'<'`` for little endian. If is ``None``, it will either
be the endianness of the first Trace or if that is also not set, it
will be big endian. A mix between little and big endian for the headers
and traces is currently not supported.
This function will automatically set the data encoding field of the binary
file header so the user does not need to worry about it.
"""
# Check that the dtype for every Trace is correct.
for trace in stream:
# Check the dtype.
if trace.data.dtype != 'float32':
msg = """
The dtype of the data is not float32. You need to manually convert
the dtype. Please refer to the obspy.segy manual for more details.
""".strip()
raise SEGYCoreWritingError(msg)
# Check the sample interval.
if trace.stats.delta > MAX_INTERVAL_IN_SECONDS:
msg = """
Seismic Unix supports a maximum interval of %s seconds in between
two samples (trace.stats.delta value).
""".strip()
msg = msg % MAX_INTERVAL_IN_SECONDS
raise SEGYSampleIntervalError(msg)
# Figure out endianness and the encoding of the textual file header.
if byteorder is None:
if hasattr(stream[0].stats, 'su') and hasattr(stream[0].stats.su,
'endian'):
byteorder = stream[0].stats.su.endian
else:
byteorder = '>'
# Loop over all Traces and create a SEGY File object.
su_file = SUFile()
# Add all traces.
for trace in stream:
new_trace = SEGYTrace()
new_trace.data = trace.data
# Use header saved in stats if one exists.
if hasattr(trace.stats, 'su') and \
hasattr(trace.stats.su, 'trace_header'):
this_trace_header = trace.stats.su.trace_header
else:
this_trace_header = AttribDict()
new_trace_header = new_trace.header
# Again loop over all field of the trace header and if they exists, set
# them. Ignore all additional attributes.
for _, item, _, _ in TRACE_HEADER_FORMAT:
if hasattr(this_trace_header, item):
setattr(new_trace_header, item,
getattr(this_trace_header, item))
starttime = trace.stats.starttime
# Set some special attributes, e.g. the sample count and other stuff.
new_trace_header.number_of_samples_in_this_trace = trace.stats.npts
new_trace_header.sample_interval_in_ms_for_this_trace = \
int(round((trace.stats.delta * 1E6)))
# Set the date of the Trace if it is not UTCDateTime(0).
if starttime == UTCDateTime(0):
new_trace.header.year_data_recorded = 0
new_trace.header.day_of_year = 0
new_trace.header.hour_of_day = 0
new_trace.header.minute_of_hour = 0
new_trace.header.second_of_minute = 0
else:
new_trace.header.year_data_recorded = starttime.year
new_trace.header.day_of_year = starttime.julday
new_trace.header.hour_of_day = starttime.hour
new_trace.header.minute_of_hour = starttime.minute
new_trace.header.second_of_minute = starttime.second
# Set the data encoding and the endianness.
new_trace.endian = byteorder
# Add the trace to the SEGYFile object.
su_file.traces.append(new_trace)
# Write the file
su_file.write(filename, endian=byteorder)
def writeSEGY(stream,
filename,
data_encoding=None,
byteorder=None,
textual_header_encoding=None,
**kwargs): # @UnusedVariable
"""
Writes a SEG Y file from given ObsPy Stream object.
.. warning::
This function should NOT be called directly, it registers via the
the :meth:`~obspy.core.stream.Stream.write` method of an
ObsPy :class:`~obspy.core.stream.Stream` object, call this instead.
:type stream: :class:`~obspy.core.stream.Stream`
:param stream: The ObsPy Stream object to write.
:type filename: str
:param filename: Name of file to write.
:type data_encoding: int
:param data_encoding: The data encoding is an integer with the following
currently supported meaning:
``1``
4 byte IBM floating points (float32)
``2``
4 byte Integers (int32)
``3``
2 byte Integer (int16)
``5``
4 byte IEEE floating points (float32)
The value in the brackets is the necessary dtype of the data. ObsPy
will now automatically convert the data because data might change/loose
precision during the conversion so the user has to take care of the
correct dtype.
If it is ``None``, the value of the first Trace will be used for all
consecutive Traces. If it is None for the first Trace, 1 (IBM floating
point numbers) will be used. Different data encodings for different
traces are currently not supported because these will most likely not
be readable by other software.
:type byteorder: ``'<'``, ``'>'``, or ``None``
:param byteorder: Determines the endianness of the file. Either ``'>'`` for
big endian or ``'<'`` for little endian. If is ``None``, it will either
be the endianness of the first Trace or if that is also not set, it
will be big endian. A mix between little and big endian for the headers
and traces is currently not supported.
:type textual_header_encoding: ``'EBCDIC'``, ``'ASCII'`` or ``None``
:param textual_header_encoding: The encoding of the textual header. If it
is ``None``, the textual_file_header_encoding attribute in the
stats.segy dictionary of the first Trace is used and if that is not
set, ASCII will be used.
This function will automatically set the data encoding field of the binary
file header so the user does not need to worry about it.
The starttime of every trace is not a required field in the SEG Y
specification. If the starttime of a trace is UTCDateTime(0) it will be
interpreted as a not-set starttime and no time is written to the trace
header. Every other time will be written.
SEG Y supports a sample interval from 1 to 65535 microseconds in steps of 1
microsecond. Larger intervals cannot be supported due to the definition of
the SEG Y format. Therefore the smallest possible sampling rate is ~ 15.26
Hz. Please keep that in mind.
"""
# Some sanity checks to catch invalid arguments/keyword arguments.
if data_encoding is not None and data_encoding not in VALID_FORMATS:
msg = "Invalid data encoding."
raise SEGYCoreWritingError(msg)
# Figure out the data encoding if it is not set.
if data_encoding is None:
if hasattr(stream, 'stats') and hasattr(stream.stats, 'data_encoding'):
data_encoding = stream.stats.data_encoding
if hasattr(stream, 'stats') and hasattr(stream.stats,
'binary_file_header'):
data_encoding = \
stream.stats.binary_file_header.data_sample_format_code
# Set it to float if it in not given.
else:
data_encoding = 1
# Create empty file wide headers if they do not exist.
if not hasattr(stream, 'stats'):
stream.stats = AttribDict()
if not hasattr(stream.stats, 'textual_file_header'):
stream.stats.textual_file_header = ""
if not hasattr(stream.stats, 'binary_file_header'):
stream.stats.binary_file_header = SEGYBinaryFileHeader()
# Valid dtype for the data encoding.
valid_dtype = DATA_SAMPLE_FORMAT_CODE_DTYPE[data_encoding]
# Makes sure that the dtype is for every Trace is correct.
for trace in stream:
# Check the dtype.
if trace.data.dtype != valid_dtype:
msg = """
The dtype of the data and the chosen data_encoding do not match.
You need to manually convert the dtype if you want to use that
data_encoding. Please refer to the obspy.segy manual for more
details.
""".strip()
raise SEGYCoreWritingError(msg)
# Check the sample interval.
if trace.stats.delta > MAX_INTERVAL_IN_SECONDS:
msg = """
SEG Y supports a maximum interval of %s seconds in between two
samples (trace.stats.delta value).
""".strip()
msg = msg % MAX_INTERVAL_IN_SECONDS
raise SEGYSampleIntervalError(msg)
# Figure out endianness and the encoding of the textual file header.
if byteorder is None:
if hasattr(stream, 'stats') and hasattr(stream.stats, 'endian'):
byteorder = stream.stats.endian
else:
byteorder = '>'
# Map the byteorder.
byteorder = ENDIAN[byteorder]
if textual_header_encoding is None:
if hasattr(stream, 'stats') and hasattr(
stream.stats, 'textual_file_header_encoding'):
textual_header_encoding = \
stream.stats.textual_file_header_encoding
else:
textual_header_encoding = 'ASCII'
# Loop over all Traces and create a SEGY File object.
segy_file = SEGYFile()
# Set the file wide headers.
segy_file.textual_file_header = stream.stats.textual_file_header
segy_file.textual_header_encoding = \
textual_header_encoding
binary_header = SEGYBinaryFileHeader()
this_binary_header = stream.stats.binary_file_header
# Loop over all items and if they exists set them. Ignore all other
# attributes.
for _, item, _ in BINARY_FILE_HEADER_FORMAT:
if hasattr(this_binary_header, item):
setattr(binary_header, item, getattr(this_binary_header, item))
# Set the data encoding.
binary_header.data_sample_format_code = data_encoding
segy_file.binary_file_header = binary_header
# Add all traces.
for trace in stream:
new_trace = SEGYTrace()
new_trace.data = trace.data
# Create empty trace header if none is there.
if not hasattr(trace.stats, 'segy'):
print "CREATING TRACE HEADER"
trace.stats.segy = {}
trace.stats.segy.trace_header = SEGYTraceHeader(endian=byteorder)
elif not hasattr(trace.stats.segy, 'trace_header'):
print "CREATING TRACE HEADER"
trace.stats.segy.trace_header = SEGYTraceHeader()
this_trace_header = trace.stats.segy.trace_header
new_trace_header = new_trace.header
# Again loop over all field of the trace header and if they exists, set
# them. Ignore all additional attributes.
for _, item, _, _ in TRACE_HEADER_FORMAT:
if hasattr(this_trace_header, item):
setattr(new_trace_header, item,
getattr(this_trace_header, item))
starttime = trace.stats.starttime
# Set the date of the Trace if it is not UTCDateTime(0).
if starttime == UTCDateTime(0):
new_trace.header.year_data_recorded = 0
new_trace.header.day_of_year = 0
new_trace.header.hour_of_day = 0
new_trace.header.minute_of_hour = 0
new_trace.header.second_of_minute = 0
else:
new_trace.header.year_data_recorded = starttime.year
new_trace.header.day_of_year = starttime.julday
new_trace.header.hour_of_day = starttime.hour
new_trace.header.minute_of_hour = starttime.minute
new_trace.header.second_of_minute = starttime.second
# Set the sampling rate.
new_trace.header.sample_interval_in_ms_for_this_trace = \
int(trace.stats.delta * 1E6)
# Set the data encoding and the endianness.
new_trace.data_encoding = data_encoding
new_trace.endian = byteorder
# Add the trace to the SEGYFile object.
segy_file.traces.append(new_trace)
# Write the file
segy_file.write(filename, data_encoding=data_encoding, endian=byteorder)