obspy.mseed - MiniSEED read and write support¶
This module provides read and write support for the MiniSEED (and the data part of full SEED) waveform data format and some other convenient methods to handle MiniSEED files. It utilizes libmseed, a C library by Chad Trabant.
The format is defined in the SEED Manual.
|copyright:||The ObsPy Development Team (firstname.lastname@example.org) & Chad Trabant|
|license:||GNU Lesser General Public License, Version 3 (http://www.gnu.org/copyleft/lesser.html)|
Reading MiniSEED (and the data part of full SEED files) is handled by using ObsPy’s standard read() function. The format is detected automatically.
>>> from obspy import read >>> st = read("/path/to/test.mseed") >>> st <obspy.core.stream.Stream object at 0x...> >>> print(st) 1 Trace(s) in Stream: NL.HGN.00.BHZ | 2003-05-29T02:13:22.043400Z - ... | 40.0 Hz, 11947 samples >>> print(st.stats) network: NL station: HGN location: 00 channel: BHZ starttime: 2003-05-29T02:13:22.043400Z endtime: 2003-05-29T02:18:20.693400Z sampling_rate: 40.0 delta: 0.025 npts: 11947 calib: 1.0 _format: MSEED mseed: ...
MiniSEED specific metadata is stored in stats.mseed.
>>> for k, v in sorted(st.stats.mseed.items()): ... print("'%s': %s" % (k, str(v))) 'byteorder': > 'dataquality': R 'encoding': STEIM2 'filesize': 8192 'number_of_records': 2 'record_length': 4096
The actual data is stored as a ndarray in the data attribute of each trace.
>>> print(st.data) [2787 2776 2774 ..., 2850 2853 2853]
Several key word arguments are available which can be used for example to only read certain records from a file or force the header byteorder: starttime, endtime, headonly, sourcename, reclen, details, and header_byteorder. They are passed to the readMSEED() method so refer to it for details to each parameter.
>>> st.write('Mini-SEED-filename.mseed', format='MSEED')
You can also specify several keyword arguments that change the resulting Mini-SEED file: reclen, encoding, byteorder, flush, and verbose. They are are passed to the writeMSEED() method so refer to it for details to each parameter.
Refer to the writeMSEED() method for details to each parameter.
So in order to write a STEIM1 encoded Mini-SEED file with a record length of 512 byte do the following:
>>> st.write('out.mseed', format='MSEED', reclen=512, ... encoding='STEIM1')
Many of these can also be set at each Trace`s stats.mseed attribute which allows for per Trace granularity. Values passed to the read() function have priority.
MiniSEED is a format with a large variety of different blockettes, byte order issues, and encodings. The capabilities of obspy.mseed largely coincide with the capabilities of libmseed, which is the de-facto standard MiniSEED library and used internally by ObsPy.
In regards to the different encodings for the data part of MiniSEED files this means the following:
- Read support for: ACSII, 16 and 32 bit integers, 32 and 64 bit floats, STEIM 1 + 2, all GEOSCOPE encodings, the CDSN encoding, the SRO encoding, and the DWWSSN encoding
- Write support for: ACSII, 16 and 32 bit integers, 32 and 64 bit floats, and STEIM 1 + 2
- Unsupported: 24 bit integers, US National Network compression, Graefenberg 16 bit gain ranged encoding, IPG - Strasbourg 16 bit gain ranged encoding, STEIM 3, the HGLP encoding, and the RSTN 16 bit gain ranged encoding
This module also contains a couple of utility functions which are useful for some purposes. Refer to the documentation of each for details.
|getStartAndEndTime()||Fast way of getting the temporal bounds of a well-behaved MiniSEED file.|
|getTimingAndDataQuality()||Returns information about the data and timing quality flags in a file.|
|shiftTimeOfFile()||Shifts the time of a file preserving all blockettes and flags.|
|getRecordInformation()||Returns record information about given files and file-like object.|
|set_flags_in_fixed_headers()||Updates a given miniSEED file with some fixed header flags.|