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__	str(object=’‘) -> str
__hash__
__module__	str(object=’‘) -> str
__weakref__	list of weak references to the object (if defined)
have_appended_data	bool(x) -> bool
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
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. Spectra are linearly
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
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
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
_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.
__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. SEGY object do not
__subclasshook__	Abstract classes can override this to customize issubclass().
__truediv__	Split Trace into new Stream containing num Traces of the same size.