spacepy.plot.spectrogram

Create and plot generic ‘spectrograms’ for space science. This is not a signal processing routine and does not apply Fourier transforms (or similar) to the data. The functionality provided here is the binning (and averaging) of multi-dimensional to provide a 2D output map of some quantity as a function of two parameters. An example would be particle data from a satellite mission: electron flux, at a given energy, can be binned as a function of both time and McIlwain L, then plotted as a 2D color-map, colloquially known as a spectrogram.

In many other settings ‘spectrogram’ refers to a transform of data from the time domain to the frequency domain, and the subsequent plotting of some quantity (e.g., power spectral density) as a function of time and frequency. To approximate this functionality for, e.g., time-series magnetic field data you would first calculate a the power spectral density and then use Spectrogram to rebin the data for visualization.

Authors: Brian Larsen and Steve Morley Institution: Los Alamos National Laboratory Contact: balarsen@lanl.gov, smorley@lanl.gov Los Alamos National Laboratory

Copyright 2011 Los Alamos National Security, LLC.

Functions

simpleSpectrogram(*args, **kwargs)

Plot a spectrogram given Z or X,Y,Z.

Classes

Spectrogram(data, **kwargs)

This class rebins data to produce a 2D data map that can be plotted as a spectrogram

spacepy.plot.spectrogram.simpleSpectrogram(*args, **kwargs)

Plot a spectrogram given Z or X,Y,Z. This is a wrapper around pcolormesh() that can handle Y being a 2d array of time dependent bins. Like in the Van Allen Probes HOPE and MagEIS data files.

Parameters:

*args1 or 3 arraylike

Call Signatures:

simpleSpectrogram(Z, **kwargs)
simpleSpectrogram(X, Y, Z, **kwargs)

Returns:

axmatplotlib.axes._subplots.AxesSubplot

Matplotlib axes object that the plot is on

Other Parameters:

zlogbool

Plot the color with a log colorbar (default: True)

ylogbool

Plot the Y axis with a log scale (default: True)

alphascalar (0-1)

The alpha blending value (default: None)

cmapstring

The name of the colormap to use (default: system default)

vminfloat

Minimum color value (default: Z.min(), if log non-zero min)

vmaxfloat

Maximum color value (default: Z.max())

axmatplotlib.axes

Axes to plot the spectrogram on (default: None - new axes)

cbbool

Plot a colorbar (default: True)

cbtitlestring

Label to go on the colorbar (default: None)

zero_validbool

Treat zero as a valid value on zlog plots and use same color as other under-minimum values. No effect with linear colorbar. (default: False, draw as fill)

Added in version 0.5.0.