rgbmesh

named_arrays.plt.rgbmesh(*WXY, C, axis_wavelength, ax=None, norm=None, vmin=None, vmax=None, wavelength_norm=None, wavelength_min=None, wavelength_max=None, **kwargs)

A convenience function that calls pcolormesh() with the outputs from named_arrays.colorsynth.rgb() and returns a colorbar.

This allows us to plot 3D cubes, with the third dimension being represented by color, using a pcolormesh()-like interface.

Parameters:

• WXY (AbstractScalar | AbstractCartesian2dVectorArray | AbstractSpectralPositionalVectorArray) – The coordinates of the mesh to plot. Allowed combinations are: an instance of named_arrays.AbstractSpectralPositionalVectorArray, an instance of named_arrays.AbstractScalar and an instance of named_arrays.AbstractCartesian2dVectorArray or three instances of named_arrays.AbstractScalar.

• C (AbstractScalar) – The mesh data.

• axis_wavelength (str) – The logical axis representing changing wavelength coordinate.

• ax (None | Axes | AbstractArray) – The instances of matplotlib.axes.Axes to use. If None, calls matplotlib.pyplot.gca() to get the current axes. If an instance of named_arrays.ScalarArray, ax.shape should be a subset of the broadcasted shape of *args.

• norm (None | Callable) – An optional function that transforms the spectral power distribution values before mapping to RGB. Equivalent to the spd_norm argument of named_arrays.colorsynth.rgb().

• vmin (None | int | float | complex | ndarray | Quantity | AbstractArray) – The value of the spectral power distribution representing minimum intensity. Equivalent to the spd_min argument of named_arrays.colorsynth.rgb().

• vmax (None | int | float | complex | ndarray | Quantity | AbstractArray) – The value of the spectral power distribution representing maximum intensity. Equivalent to the spd_max argument of named_arrays.colorsynth.rgb().

• wavelength_norm (None | Callable) – An optional function to transform the wavelength values before they are mapped into the human visible color range.

• wavelength_min (None | float | Quantity | AbstractScalar) – The wavelength value that is mapped to the minimum wavelength of the human visible color range, 380 nm.

• wavelength_max (None | float | Quantity | AbstractScalar) – The wavelength value that is mapped to the maximum wavelength of the human visible color range, 700 nm

• kwargs – Additional keyword arguments passed to matplotlib.pyplot.pcolormesh().

Return type:

FunctionArray[Cartesian2dVectorArray, AbstractScalar]

Examples

Plot a random, 3D cube.

import matplotlib.pyplot as plt
import astropy.units as u
import astropy.visualization
import named_arrays as na

# Define a random 3d cube
a = na.random.uniform(
    low=0 * u.photon,
    high=1000 * u.photon,
    shape_random=dict(x=16, y=16, wavelength=11),
)

# Define wavelength coordinates
wavelength = na.linspace(
    start=100 * u.AA,
    stop=200 * u.AA,
    axis="wavelength",
    num=a.shape["wavelength"],
)

# Define spatial coordinates
x = na.linspace(-1, 1, axis="x", num=a.shape["x"]) * u.mm
y = na.linspace(-1, 1, axis="y", num=a.shape["y"]) * u.mm

# Plot the colorbar
with astropy.visualization.quantity_support():
    fig, axs = plt.subplots(
        ncols=2,
        gridspec_kw=dict(width_ratios=[.9,.1]),
        constrained_layout=True,
    )
    colorbar = na.plt.rgbmesh(
        wavelength, x, y,
        C=a,
        axis_wavelength="wavelength",
        ax=axs[0],
    );
    na.plt.pcolormesh(
        C=colorbar,
        axis_rgb="wavelength",
        ax=axs[1],
    )
    axs[1].yaxis.tick_right()
    axs[1].yaxis.set_label_position("right")