map_plot¶

MATLAB equivalent: sidMapPlot

map_plot ¶

Time-frequency colour map for sidFreqMap results.

map_plot ¶

map_plot(result: FreqMapResult, *, plot_type: str = 'magnitude', frequency_unit: str = 'rad/s', clim: tuple | None = None, ax=None) -> dict

Time-frequency colour map for :func:sid.freq_map results.

This is the Python port of sidMapPlot.m.

Plots the time-varying frequency response (or spectrum / coherence) as a pcolormesh colour map with time on the x-axis and frequency (log scale) on the y-axis.

Parameters:

Name	Type	Description	Default
`result`	`FreqMapResult`	Result struct returned by :func:`sid.freq_map`. Must have `method == 'freq_map'`.	required
`plot_type`	`str`	What to plot: `'magnitude'` -- `20 * log10(\|G(w,t)\|)` in dB (default). `'phase'` -- `angle(G(w,t))` in degrees. `'noise'` -- `10 * log10(noise_spectrum)` in dB. `'coherence'` -- squared coherence on `[0, 1]`. `'spectrum'` -- `10 * log10(noise_spectrum)` in dB (alias for time-series data).	`'magnitude'`
`frequency_unit`	`str`	`'rad/s'` (default) or `'Hz'`.	`'rad/s'`
`clim`	`tuple of (float, float) or None`	Colour axis limits `(cmin, cmax)`. `None` for automatic scaling (default).	`None`
`ax`	`matplotlib Axes or None`	Existing axes to plot into. If `None`, a new figure is created.	`None`

Returns:

Type	Description
`dict`	Dictionary with the following keys: `'fig'` -- matplotlib Figure handle. `'ax'` -- Axes handle. `'mesh'` -- QuadMesh handle from `pcolormesh`.

Raises:

Type	Description
`SidError`	If result is not a `FreqMapResult` (code: `'invalid_result'`).
`SidError`	If plot_type requires a frequency response but the result is time-series only (code: `'no_response'`).
`SidError`	If plot_type is `'coherence'` but no coherence data is available (code: `'no_coherence'`).
`SidError`	If plot_type is unrecognised (code: `'invalid_plot_type'`).

Examples:

>>> import numpy as np
>>> import sid
>>> N = 4000; u = np.random.randn(N)
>>> y = np.convolve(u, [1, -0.9])[:N] + 0.1 * np.random.randn(N)
>>> result = sid.freq_map(y, u, segment_length=512)
>>> h = sid.map_plot(result, plot_type='magnitude')

Notes

Specification: SPEC.md S6.9 -- Visualization: sidMapPlot