ReadLIGO

This module provides tools for reading LIGO data files. Data along with supporting documentation can be downloaded from the GWOSC web site.

Installation

To install download the repo and install with pip

git clone https://git.ligo.org/gwosc/readligo.git; cd readligo
pip install .

Documentation

Some possible use cases are shown below.

Example 0

To load all data from a single file:

strain, time, dq = rl.loaddata("ligo_data/H-H1_LOSC_4_V1-842653696-4096.hdf5", "H1")

Some GWF files require parameters to name the strain, DQ, and hardware injection channel:

strain, time, dq = rl.loaddata(
    "H-H1_LOSC_16_V1-1127415808-4096.gwf",
    "H1",
    strain_chan="H1:GWOSC-16KHZ_R1_STRAIN", 
    dq_chan="H1:GWOSC-16KHZ_R1_DQMASK",
    inj_chan="H1:GWOSC-16KHZ_R1_INJMASK"
)

Example 1

This default configuration assumes that the needed LIGO data files are available in the current working directory or a subdirectory. LIGO data between the input GPS times are loaded into STRAIN. META is a dictionary of gps start, gps stop, and the sample time. DQ is a dictionary of data quality flags.

segList = getsegs(842657792, 842658792, 'H1')
for (start, stop) in segList:
  strain, meta, dq = getstrain(start, stop, 'H1')
  # -- Analysis code here
  ...

Example 2

In Example 2, H1_segs.txt is a segment list downloaded from the GWOSC web site using the Timeline application. This may be used in the same manner as segList in example 1.

segList = SegmentList("H1_segs.txt")

Example 3

In this example, the first command searches the indicated directory and sub-directories for LIGO data files. This list of data files is then used to construct a segment list and load the requested data.

filelist = FileList(directory="/home/ligodata")
segList = getsegs(842657792, 842658792, "H1", filelist=filelist)
for start, stop in segList:
  strain, meta, dq = getstrain(start, stop, "H1", filelist=filelist)
  # -- Analysis code here

Segment Lists

Segment lists may be downloaded from the GWOSC web site using the Timeline Query Form or constructed directly from the data files.

Read in a segment list downloaded from the Timeline application on the GWOSC web site with SegmentList.

from readligo import SegmentList
seglist = SegmentList("H1_segs.txt")

Or Construct a segment list directly from the LIGO data files with getsegs.

from readligo import getsegs
seglist = getsegs(842657792, 842658792, 'H1', flag='DATA', filelist=None)