obspy.realtime.rttrace.RtTrace

class RtTrace(max_length=None, *args, **kwargs)[source]

Bases: obspy.core.trace.Trace

An object containing data of a continuous series constructed dynamically from sequential data packets.

New data packets may be periodically appended. Registered time-domain processes can be applied to the new data and the resulting trace will be left trimmed to maintain a specified maximum trace length.

Parameters

max_length (int, optional) – maximum trace length in seconds

Example

RtTrace has been built to handle real time processing of periodically append data packets, such as adding and processing data requested from an SeedLink server. See obspy.clients.seedlink for further information.

For the sake of simplicity we will just split data of an existing example file into multiple chucks (Trace objects) of about equal size (step 1 + 2) and append those chunks in a simple loop (step 4) into an RtTrace object. Additionally there are two real time processing functions registered to the RtTrace object (step 3) which will automatically process any appended data chunks.

  1. Read first trace of example SAC data file and extract contained time offset and epicentral distance of an earthquake:

    >>> from obspy.realtime import RtTrace
    >>> from obspy import read
    >>> from obspy.realtime.signal import calculate_mwp_mag
    >>> data_trace = read('/path/to/II.TLY.BHZ.SAC')[0]
    >>> len(data_trace)
    12684
    >>> ref_time_offset = data_trace.stats.sac.a
    >>> print(ref_time_offset)
    301.506
    >>> epicentral_distance = data_trace.stats.sac.gcarc
    >>> print(epicentral_distance)
    30.0855
    
  2. Split given trace into a list of three sub-traces:

    >>> traces = data_trace / 3
    >>> [len(tr) for tr in traces]
    [4228, 4228, 4228]
    
  3. Assemble real time trace and register two processes:

    >>> rt_trace = RtTrace()
    >>> rt_trace.register_rt_process('integrate')
    1
    >>> rt_trace.register_rt_process('mwpintegral', mem_time=240,
    ...     ref_time=(data_trace.stats.starttime + ref_time_offset),
    ...     max_time=120, gain=1.610210e+09)
    2
    
  4. Append and auto-process packet data into RtTrace:

    >>> for tr in traces:
    ...     processed_trace = rt_trace.append(tr, gap_overlap_check=True)
    ...
    >>> len(rt_trace)
    12684
    
  5. Some post processing to get Mwp:

    >>> peak = np.amax(np.abs(rt_trace.data))
    >>> print(peak)
    0.136404
    >>> mwp = calculate_mwp_mag(peak, epicentral_distance)
    >>> print(mwp)  
    8.78902911791...
    

Attributes

__dict__

__doc__

__hash__

__module__

__weakref__

list of weak references to the object (if defined)

have_appended_data

id

Return a SEED compatible identifier of the trace.

meta

Public Methods

append

Appends a Trace object to this RtTrace.

attach_response

Search for and attach channel response to the trace as Trace.stats.response.

copy

Returns a deepcopy of this RtTrace.

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.

register_rt_process

Adds real-time processing algorithm to processing list of this RtTrace.

remove_response

Deconvolve instrument response.

remove_sensitivity

Remove instrument sensitivity.

resample

Resample trace data using Fourier method.

rt_process_functions_to_string

Return doc string for all predefined real-time processing functions.

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.

_get_response

Search for and return channel response for the trace.

_internal_add_processing_info

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

_ltrim

Cut current trace to given start time.

_repr_pretty_

_rtrim

Cut current trace to given end time.

Special Methods

__add__

Too ambiguous, throw an Error.

__dir__

Default dir() implementation.

__div__

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

__eq__

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

__format__

Default object formatter.

__ge__

Too ambiguous, throw an Error.

__getitem__

__getitem__ method of Trace object.

__gt__

Too ambiguous, throw an Error.

__init__

Initializes an RtTrace.

__init_subclass__

This method is called when a class is subclassed.

__le__

Too ambiguous, throw an Error.

__len__

Return number of data samples of the current trace.

__lt__

Too ambiguous, throw an Error.

__mod__

Split Trace into new Stream containing Traces with num samples.

__mul__

Create a new Stream containing num copies of this trace.

__ne__

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

__new__

Create and return a new object.

__nonzero__

No data means no trace.

__original_str__

Return short summary string of the current trace.

__reduce__

Helper for pickle.

__reduce_ex__

Helper for pickle.

__setattr__

__setattr__ method of Trace object.

__sizeof__

Size of object in memory, in bytes.

__str__

Monkey patch for the __str__ method of the Trace object.

__subclasshook__

Abstract classes can override this to customize issubclass().

__truediv__

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