obspy.core.trace.Trace

class Trace(data=array([], dtype=float64), header=None)

Bases: object

An object containing data of a continuous series, such as a seismic trace.

Parameters:

• data (ndarray or MaskedArray) – Array of data samples

• header (dict or Stats) – Dictionary containing header fields

Variables:

• id – A SEED compatible identifier of the trace.

• stats – A container Stats for additional header information of the trace.

• data – Data samples in a ndarray or MaskedArray

Note

The .data attribute containing the time series samples as a numpy.ndarray will always be made contiguous in memory. This way it is always safe to use .data in routines that internally pass the array to C code. On the other hand this might result in some unwanted copying of data in memory. Experts can opt-out by setting Trace._always_contiguous = False, in this case the user has to make sure themselves that no C operations are performed on potentially incontiguous data.

Supported Operations

trace = traceA + traceB

Merges traceA and traceB into one new trace object. See also: Trace.__add__().

len(trace)

Returns the number of samples contained in the trace. That is it es equal to len(trace.data). See also: Trace.__len__().

str(trace)

Returns basic information about the trace object. See also: Trace.__str__().

Attributes

id	Return a SEED compatible identifier of the trace.
meta

Public Methods

attach_response	Search for and attach channel response to the trace as obspy.core.trace.Trace.stats.response.
copy	Returns a deepcopy of the trace.
count	Return number of data samples of the current trace.
decimate	Downsample trace data by an integer factor.
detrend	Remove a trend from the trace.
differentiate	Differentiate the trace with respect to time.
filter	Filter the data of the current trace.
get_id	Return a SEED compatible identifier of the trace.
integrate	Integrate the trace with respect to time.
interpolate	Interpolate the data using various interpolation techniques.
max	Returns the value of the absolute maximum amplitude in the trace.
normalize	Normalize the trace to its absolute maximum.
plot	Create a simple graph of the current trace.
remove_response	Deconvolve instrument response.
remove_sensitivity	Remove instrument sensitivity.
resample	Resample trace data using Fourier method.
simulate	Correct for instrument response / Simulate new instrument response.
slice	Return a new Trace object with data going from start to end time.
slide	Generator yielding equal length sliding windows of the Trace.
spectrogram	Create a spectrogram plot of the trace.
split	Split Trace object containing gaps using a NumPy masked array into several traces.
std	Method to get the standard deviation of amplitudes in the trace.
taper	Taper the trace.
times	For convenient plotting compute a NumPy array with timing information of all samples in the Trace.
trigger	Run a triggering algorithm on the data of the current trace.
trim	Cut current trace to given start and end time.
verify	Verify current trace object against available meta data.
write	Save current trace into a file.

Private Methods

Warning

Private methods are mainly for internal/developer use and their API might change without notice.

Trace._get_response(inventories)

Search for and return channel response for the trace.

Parameters:

inventories (Inventory or Network or a list containing objects of these types or a string with a filename of a StationXML file.) – Station metadata to use in search for response for each trace in the stream.

Returns:

obspy.core.inventory.response.Response object

Trace._internal_add_processing_info(info)

Add the given informational string to the processing field in the trace’s Stats object.

Trace._ltrim(starttime, pad=False, nearest_sample=True, fill_value=None)

Cut current trace to given start time. For more info see trim().

Example

>>> tr = Trace(data=np.arange(0, 10))
>>> tr.stats.delta = 1.0
>>> tr._ltrim(tr.stats.starttime + 8)  
<...Trace object at 0x...>
>>> tr.data
array([8, 9])
>>> tr.stats.starttime
UTCDateTime(1970, 1, 1, 0, 0, 8)

Trace._repr_pretty_(p, cycle)

Trace._rtrim(endtime, pad=False, nearest_sample=True, fill_value=None)

Cut current trace to given end time. For more info see trim().

Example

>>> tr = Trace(data=np.arange(0, 10))
>>> tr.stats.delta = 1.0
>>> tr._rtrim(tr.stats.starttime + 2)  
<...Trace object at 0x...>
>>> tr.data
array([0, 1, 2])
>>> tr.stats.endtime
UTCDateTime(1970, 1, 1, 0, 0, 2)

Special Methods

Trace.__add__(trace, method=0, interpolation_samples=0, fill_value=None, sanity_checks=True)

Add another Trace object to current trace.

Parameters:

• method (int, optional) – Method to handle overlaps of traces. Defaults to 0. See the Handling Overlaps section below for further details.

• fill_value (int, float, str or None, optional) – Fill value for gaps. Defaults to None. Traces will be converted to NumPy masked arrays if no value is given and gaps are present. If the keyword 'latest' is provided it will use the latest value before the gap. If keyword 'interpolate' is provided, missing values are linearly interpolated (not changing the data type e.g. of integer valued traces). See the Handling Gaps section below for further details.

• interpolation_samples (int, optional) – Used only for method=1. It specifies the number of samples which are used to interpolate between overlapping traces. Defaults to 0. If set to -1 all overlapping samples are interpolated.

• sanity_checks (bool, optional) – Enables some sanity checks before merging traces. Defaults to True.

Trace data will be converted into a NumPy masked array data type if any gaps are present. This behavior may be prevented by setting the fill_value parameter. The method argument controls the handling of overlapping data values.

Sampling rate, data type and trace.id of both traces must match.

Handling Overlaps

Method	Description
0	Discard overlapping data. Overlaps are essentially treated the same way as gaps: Trace 1: AAAAAAAA Trace 2: FFFFFFFF 1 + 2 : AAAA----FFFF Contained traces with differing data will be marked as gap: Trace 1: AAAAAAAAAAAA Trace 2: FF 1 + 2 : AAAA--AAAAAA Missing data can be merged in from a different trace: Trace 1: AAAA--AAAAAA (contained trace, missing samples) Trace 2: FF 1 + 2 : AAAAFFAAAAAA
1	Discard data of the previous trace assuming the following trace contains data with a more correct time value. The parameter interpolation_samples specifies the number of samples used to linearly interpolate between the two traces in order to prevent steps. Note that if there are gaps inside, the returned array is still a masked array, only if fill_value is set, the returned array is a normal array and gaps are filled with fill value. No interpolation (interpolation_samples=0): Trace 1: AAAAAAAA Trace 2: FFFFFFFF 1 + 2 : AAAAFFFFFFFF Interpolate first two samples (interpolation_samples=2): Trace 1: AAAAAAAA Trace 2: FFFFFFFF 1 + 2 : AAAACDFFFFFF (interpolation_samples=2) Interpolate all samples (interpolation_samples=-1): Trace 1: AAAAAAAA Trace 2: FFFFFFFF 1 + 2 : AAAABCDEFFFF Any contained traces with different data will be discarded: Trace 1: AAAAAAAAAAAA (contained trace) Trace 2: FF 1 + 2 : AAAAAAAAAAAA Missing data can be merged in from a different trace: Trace 1: AAAA--AAAAAA (contained trace, missing samples) Trace 2: FF 1 + 2 : AAAAFFAAAAAA

Handling gaps

1. Traces with gaps and fill_value=None (default):

   Trace 1: AAAA
   Trace 2:         FFFF
   1 + 2  : AAAA----FFFF
   

2. Traces with gaps and given fill_value=0:

   Trace 1: AAAA
   Trace 2:         FFFF
   1 + 2  : AAAA0000FFFF
   

3. Traces with gaps and given fill_value='latest':

   Trace 1: ABCD
   Trace 2:         FFFF
   1 + 2  : ABCDDDDDFFFF
   

4. Traces with gaps and given fill_value='interpolate':

   Trace 1: AAAA
   Trace 2:         FFFF
   1 + 2  : AAAABCDEFFFF
   

Trace.__delattr__(name, /)

Implement delattr(self, name).

Trace.__dir__()

Default dir() implementation.

Trace.__eq__(other)

Implements rich comparison of Trace objects for “==” operator.

Traces are the same, if both their data and stats are the same.

Trace.__format__(format_spec, /)

Default object formatter.

Trace.__ge__(other)

Too ambiguous, throw an Error.

Trace.__getattribute__(name, /)

Return getattr(self, name).

Trace.__getitem__(index)

__getitem__ method of Trace object.

Return type:

list

Returns:

List of data points

Trace.__gt__(other)

Too ambiguous, throw an Error.

Trace.__init__(data=array([], dtype=float64), header=None)

Trace.__init_subclass__()

This method is called when a class is subclassed.

The default implementation does nothing. It may be overridden to extend subclasses.

Trace.__le__(other)

Too ambiguous, throw an Error.

Trace.__len__()

Return number of data samples of the current trace.

Return type:

int

Returns:

Number of data samples.

Example

>>> trace = Trace(data=np.array([1, 2, 3, 4]))
>>> trace.count()
4
>>> len(trace)
4

Trace.__lt__(other)

Too ambiguous, throw an Error.

Trace.__mod__(num)

Split Trace into new Stream containing Traces with num samples.

Parameters:

num (int) – Number of samples in each trace in returned Stream. Last trace may contain lesser samples.

Returns:

New ObsPy Stream object.

Example

>>> from obspy import read
>>> tr = read()[0]
>>> print(tr)  
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z ... | 100.0 Hz, 3000 samples
>>> st = tr % 800
>>> print(st)  
4 Trace(s) in Stream:
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z ... | 100.0 Hz, 800 samples
BW.RJOB..EHZ | 2009-08-24T00:20:11.000000Z ... | 100.0 Hz, 800 samples
BW.RJOB..EHZ | 2009-08-24T00:20:19.000000Z ... | 100.0 Hz, 800 samples
BW.RJOB..EHZ | 2009-08-24T00:20:27.000000Z ... | 100.0 Hz, 600 samples

Trace.__mul__(num)

Create a new Stream containing num copies of this trace.

Parameters:

num (int) – Number of copies.

Returns:

New ObsPy Stream object.

Example

>>> from obspy import read
>>> tr = read()[0]
>>> st = tr * 5
>>> len(st)
5

Trace.__ne__(other)

Implements rich comparison of Trace objects for “!=” operator.

Calls __eq__() and returns the opposite.

Trace.__new__(**kwargs)

Trace.__nonzero__()

No data means no trace.

Trace.__reduce__()

Helper for pickle.

Trace.__reduce_ex__(protocol, /)

Helper for pickle.

Trace.__repr__()

Return repr(self).

Trace.__setattr__(key, value)

__setattr__ method of Trace object.

Trace.__sizeof__()

Size of object in memory, in bytes.

Trace.__str__(*args, **kwargs)

Monkey patch for the __str__ method of the Trace object. SEGY object do not have network, station, channel codes. It just prints the trace sequence number within the line.

Trace.__subclasshook__()

Abstract classes can override this to customize issubclass().

This is invoked early on by abc.ABCMeta.__subclasscheck__(). It should return True, False or NotImplemented. If it returns NotImplemented, the normal algorithm is used. Otherwise, it overrides the normal algorithm (and the outcome is cached).

Trace.__truediv__(num)

Split Trace into new Stream containing num Traces of the same size.

Parameters:

num (int) – Number of traces in returned Stream. Last trace may contain lesser samples.

Returns:

New ObsPy Stream object.

Example

>>> from obspy import read
>>> tr = read()[0]
>>> print(tr)  
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z ... | 100.0 Hz, 3000 samples
>>> st = tr / 7
>>> print(st)  
7 Trace(s) in Stream:
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:07.290000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:11.580000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:15.870000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:20.160000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:24.450000Z ... | 100.0 Hz, 429 samples
BW.RJOB..EHZ | 2009-08-24T00:20:28.740000Z ... | 100.0 Hz, 426 samples