GWpy

4.0.1 verified Fri May 01 auth: no python

GWpy is a Python package for gravitational-wave astrophysics, enabling data analysis and visualization of gravitational-wave data. Version 4.0.1 requires Python >=3.11. It provides high-level access to time series, frequency series, and spectrograms, with integration to GWOSC and other data sources. The library is under active development with regular releases.

pip install gwpy

Common errors

error ImportError: cannot import name 'TimeSeries' from 'gwpy' ↓

cause Incorrect import path: trying to import TimeSeries directly from gwpy top-level package.

fix

Use 'from gwpy.timeseries import TimeSeries' instead.

error OSError: [Errno 22] Invalid argument when opening data file ↓

cause Often due to file path containing non-ASCII characters or using Windows paths in Linux-style string.

fix

Ensure file paths are correct and use raw strings or forward slashes.

error ValueError: The given GPS end time is not in the data frame's interval ↓

cause The requested GPS time range falls outside the available data segment (e.g., detector not operating).

fix

Check the data availability using 'gwpy.segments.DataQualityFlag' or query the data range first.

error HTTPError: 401 Unauthorized when accessing NDS2 server ↓

cause Missing or invalid authentication token for NDS2 data access.

fix

Obtain a token from LIGO's datafind service and set it as GWPY_TOKEN environment variable, or pass token='your_token' to fetch methods.

Warnings

breaking In GWpy 4.0.0+, the minimum Python version is 3.11. Older Python versions (3.10, 3.9) are no longer supported. Upgrade Python if you encounter import errors. ↓

fix Ensure your environment uses Python >= 3.11. Run 'python --version' to check.

breaking Fetching data from LIGO data servers (NDS2) now requires authentication tokens. The old anonymous access is deprecated and may fail. ↓

fix Register at https://datafind.ligo.org and set environment variable 'GWPY_TOKEN' or pass 'token' argument to fetch methods.

gotcha The 'fetch_open_data' method may return data with gaps (e.g., if detector is not in science mode). Always check for missing data before analysis. ↓

fix Use the 'segmentlist' property of TimeSeries to verify coverage, or use 'DataQualityFlag' to check if data is valid.

deprecated The 'gwpy.timeseries.TimeSeriesDict' is deprecated in favor of 'gwpy.timeseries.TimeSeries' with dictionary-like access. Use 'TimeSeriesDict' only for legacy code. ↓

fix Use 'gwpy.timeseries.TimeSeries.fetch_open_data' for multiple channels or iterate over a list of frequencies.

Imports

TimeSeries
wrong
```
from gwpy import TimeSeries
```
correct
```
from gwpy.timeseries import TimeSeries
```
TimeSeries is not at top level; must import from gwpy.timeseries module.

FrequencySeries

wrong

from gwpy import FrequencySeries

correct

from gwpy.frequencyseries import FrequencySeries

Similar to TimeSeries, must use the specific submodule.

Spectrogram
```
from gwpy.spectrogram import Spectrogram
```
Spectrogram is in its own submodule; no common wrong import known.
plot
```
from gwpy.plot import Plot
```
The plotting module is 'plot' (not 'plots').

Quickstart

Fetch gravitational-wave strain data from GWOSC using a TimeSeries object. Requires internet access. The os.environ.get simulates an optional token.

from gwpy.timeseries import TimeSeries
import os

# Fetch 30 seconds of gravitational-wave strain data from GWOSC
# from the LIGO Hanford detector (H1) during GW170817
h1_data = TimeSeries.fetch_open_data(
    'H1', 1187008882, 1187008912,  # GPS start and end
    sample_rate=4096,  # Downsample to 4096 Hz
    verbose=True,
    token=os.environ.get('GWPY_TOKEN', '')
)
print(h1_data)
print('Data length:', len(h1_data), 'samples')