Python matplotlib.cm() Examples

def set_cmap(cmap):
    """
    Set the default colormap.  Applies to the current image if any.
    See help(colormaps) for more information.

    *cmap* must be a :class:`~matplotlib.colors.Colormap` instance, or
    the name of a registered colormap.

    See :func:`matplotlib.cm.register_cmap` and
    :func:`matplotlib.cm.get_cmap`.
    """
    cmap = cm.get_cmap(cmap)

    rc('image', cmap=cmap.name)
    im = gci()

    if im is not None:
        im.set_cmap(cmap)

    draw_if_interactive() 

def test_light_source_topo_surface():
    """Shades a DEM using different v.e.'s and blend modes."""
    fname = cbook.get_sample_data('jacksboro_fault_dem.npz', asfileobj=False)
    dem = np.load(fname)
    elev = dem['elevation']
    # Get the true cellsize in meters for accurate vertical exaggeration
    #   Convert from decimal degrees to meters
    dx, dy = dem['dx'], dem['dy']
    dx = 111320.0 * dx * np.cos(dem['ymin'])
    dy = 111320.0 * dy
    dem.close()

    ls = mcolors.LightSource(315, 45)
    cmap = cm.gist_earth

    fig, axes = plt.subplots(nrows=3, ncols=3)
    for row, mode in zip(axes, ['hsv', 'overlay', 'soft']):
        for ax, ve in zip(row, [0.1, 1, 10]):
            rgb = ls.shade(elev, cmap, vert_exag=ve, dx=dx, dy=dy,
                           blend_mode=mode)
            ax.imshow(rgb)
            ax.set(xticks=[], yticks=[]) 

def set_cmap(cmap):
    """
    Set the default colormap.  Applies to the current image if any.
    See help(colormaps) for more information.

    *cmap* must be a :class:`~matplotlib.colors.Colormap` instance, or
    the name of a registered colormap.

    See :func:`matplotlib.cm.register_cmap` and
    :func:`matplotlib.cm.get_cmap`.
    """
    cmap = cm.get_cmap(cmap)

    rc('image', cmap=cmap.name)
    im = gci()

    if im is not None:
        im.set_cmap(cmap) 

def spy(Z, precision=0, marker=None, markersize=None, aspect='equal', hold=None, **kwargs):
    ax = gca()
    # allow callers to override the hold state by passing hold=True|False
    washold = ax.ishold()

    if hold is not None:
        ax.hold(hold)
    try:
        ret = ax.spy(Z, precision, marker, markersize, aspect, **kwargs)
        draw_if_interactive()
    finally:
        ax.hold(washold)
    if isinstance(ret, cm.ScalarMappable):
        sci(ret)
    return ret


################# REMAINING CONTENT GENERATED BY boilerplate.py ##############


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def set_cmap(cmap):
    """
    Set the default colormap.  Applies to the current image if any.
    See help(colormaps) for more information.

    *cmap* must be a :class:`~matplotlib.colors.Colormap` instance, or
    the name of a registered colormap.

    See :func:`matplotlib.cm.register_cmap` and
    :func:`matplotlib.cm.get_cmap`.
    """
    cmap = cm.get_cmap(cmap)

    rc('image', cmap=cmap.name)
    im = gci()

    if im is not None:
        im.set_cmap(cmap)

    draw_if_interactive() 

def plotTZ(filename=None):
    cmap = cm.get_cmap('cool')
    fig, (ax1, ax2) = plt.subplots(1, 2, gridspec_kw = {'width_ratios':[19, 1]})
    ax1.add_patch(pl.Rectangle(xy=[0, 0], width=0.5, height=0.5, facecolor=cmap(0.0), linewidth='2.0'))
    ax1.add_patch(pl.Rectangle(xy=[0.5, 0.5], width=0.5, height=0.5, facecolor=cmap(0.0), linewidth='2.0'))
    ax1.add_patch(pl.Rectangle(xy=[0, 0.5], width=0.5, height=0.5, facecolor=cmap(1.0), linewidth='2.0'))
    ax1.add_patch(pl.Rectangle(xy=[0.5, 0], width=0.5, height=0.5, facecolor=cmap(1.0), linewidth='2.0'))
    ax1.set_xlabel('x1', size=22)
    ax1.set_ylabel('x2', size=22)
    ax1.set_title('True Data', size=28)
    colorbar.ColorbarBase(ax2, cmap=cmap, format='%.1f')
    ax2.set_ylabel('Output y', size=22)
    plt.show()
    if not filename is None:
        plt.savefig(filename, format="pdf", bbox_inches="tight")
        plt.close() 

def plotTZ(filename=None):
    t = np.linspace(0, 1, 101)
    z = 0.25 + 0.5 / (1 + np.exp(- 20 * (t - 0.5))) + 0.05 * np.cos(t * 2 * np.pi)
    cmap = cm.get_cmap('cool')
    fig, (ax1, ax2) = plt.subplots(1, 2, gridspec_kw = {'width_ratios':[19, 1]})
    poly1 = [[0, 0]]
    poly1.extend([[t[i], z[i]] for i in range(t.size)])
    poly1.extend([[1, 0], [0, 0]])
    poly2 = [[0, 1]]
    poly2.extend([[t[i], z[i]] for i in range(t.size)])
    poly2.extend([[1, 1], [0, 1]])
    poly1 = plt.Polygon(poly1,fc=cmap(0.0))
    poly2 = plt.Polygon(poly2,fc=cmap(1.0))
    ax1.add_patch(poly1)
    ax1.add_patch(poly2)
    ax1.set_xlabel('x1', size=22)
    ax1.set_ylabel('x2', size=22)
    ax1.set_title('True Data', size=28)
    colorbar.ColorbarBase(ax2, cmap=cmap, format='%.1f')
    ax2.set_ylabel('Output y', size=22)
    plt.show()
    if not filename is None:
        plt.savefig(filename, format="pdf", bbox_inches="tight")
        plt.close() 

def init_plot_data(self):
        a = self.fig.add_subplot(111)

        x = np.arange(120.0) * 2 * np.pi / 60.0
        y = np.arange(100.0) * 2 * np.pi / 50.0
        self.x, self.y = np.meshgrid(x, y)
        z = np.sin(self.x) + np.cos(self.y)
        self.im = a.imshow(z, cmap=cm.RdBu)  # , interpolation='nearest')

        zmax = np.max(z) - ERR_TOL
        ymax_i, xmax_i = np.nonzero(z >= zmax)
        if self.im.origin == 'upper':
            ymax_i = z.shape[0] - ymax_i
        self.lines = a.plot(xmax_i, ymax_i, 'ko')

        self.toolbar.update()  # Not sure why this is needed - ADS 

def gci():
    """
    Get the current colorable artist.  Specifically, returns the
    current :class:`~matplotlib.cm.ScalarMappable` instance (image or
    patch collection), or *None* if no images or patch collections
    have been defined.  The commands :func:`~matplotlib.pyplot.imshow`
    and :func:`~matplotlib.pyplot.figimage` create
    :class:`~matplotlib.image.Image` instances, and the commands
    :func:`~matplotlib.pyplot.pcolor` and
    :func:`~matplotlib.pyplot.scatter` create
    :class:`~matplotlib.collections.Collection` instances.  The
    current image is an attribute of the current axes, or the nearest
    earlier axes in the current figure that contains an image.
    """
    return gcf()._gci()


## Any Artist ##


# (getp is simply imported) 

def gci():
    """
    Get the current colorable artist.  Specifically, returns the
    current :class:`~matplotlib.cm.ScalarMappable` instance (image or
    patch collection), or *None* if no images or patch collections
    have been defined.  The commands :func:`~matplotlib.pyplot.imshow`
    and :func:`~matplotlib.pyplot.figimage` create
    :class:`~matplotlib.image.Image` instances, and the commands
    :func:`~matplotlib.pyplot.pcolor` and
    :func:`~matplotlib.pyplot.scatter` create
    :class:`~matplotlib.collections.Collection` instances.  The
    current image is an attribute of the current axes, or the nearest
    earlier axes in the current figure that contains an image.
    """
    return gcf()._gci()


## Any Artist ##


# (getp is simply imported) 

def set_cmap(cmap):
    """
    Set the default colormap.  Applies to the current image if any.
    See help(colormaps) for more information.

    *cmap* must be a :class:`~matplotlib.colors.Colormap` instance, or
    the name of a registered colormap.

    See :func:`matplotlib.cm.register_cmap` and
    :func:`matplotlib.cm.get_cmap`.
    """
    cmap = cm.get_cmap(cmap)

    rc('image', cmap=cmap.name)
    im = gci()

    if im is not None:
        im.set_cmap(cmap) 

def spy(Z, precision=0, marker=None, markersize=None, aspect='equal', hold=None, **kwargs):
    ax = gca()
    # allow callers to override the hold state by passing hold=True|False
    washold = ax.ishold()

    if hold is not None:
        ax.hold(hold)
    try:
        ret = ax.spy(Z, precision, marker, markersize, aspect, **kwargs)
        draw_if_interactive()
    finally:
        ax.hold(washold)
    if isinstance(ret, cm.ScalarMappable):
        sci(ret)
    return ret


################# REMAINING CONTENT GENERATED BY boilerplate.py ##############


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def apply_cmap(zs, cmap, vmin=None, vmax=None, unit=None, logrescale=False):
    '''
    apply_cmap(z, cmap) applies the given cmap to the values in z; if vmin and/or vmax are passed,
      they are used to scale z.

    Note that this function can automatically rescale data into log-space if the colormap is a
    neuropythy log-space colormap such as log_eccentricity. To enable this behaviour use the
    optional argument logrescale=True.
    '''
    zs = pimms.mag(zs) if unit is None else pimms.mag(zs, unit)
    zs = np.asarray(zs, dtype='float')
    if pimms.is_str(cmap): cmap = matplotlib.cm.get_cmap(cmap)
    if logrescale:
        if vmin is None: vmin = np.log(np.nanmin(zs))
        if vmax is None: vmax = np.log(np.nanmax(zs))
        mn = np.exp(vmin)
        u = zdivide(nanlog(zs + mn) - vmin, vmax - vmin, null=np.nan)
    else:        
        if vmin is None: vmin = np.nanmin(zs)
        if vmax is None: vmax = np.nanmax(zs)
        u = zdivide(zs - vmin, vmax - vmin, null=np.nan)
    u[np.isnan(u)] = -np.inf
    return cmap(u) 

def spy(Z, precision=0, marker=None, markersize=None, aspect='equal', hold=None, **kwargs):
    ax = gca()
    # allow callers to override the hold state by passing hold=True|False
    washold = ax.ishold()

    if hold is not None:
        ax.hold(hold)
    try:
        ret = ax.spy(Z, precision, marker, markersize, aspect, **kwargs)
        draw_if_interactive()
    finally:
        ax.hold(washold)
    if isinstance(ret, cm.ScalarMappable):
        sci(ret)
    return ret


################# REMAINING CONTENT GENERATED BY boilerplate.py ##############


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def set_cmap(cmap):
    """
    Set the default colormap.  Applies to the current image if any.
    See help(colormaps) for more information.

    *cmap* must be a :class:`~matplotlib.colors.Colormap` instance, or
    the name of a registered colormap.

    See :func:`matplotlib.cm.register_cmap` and
    :func:`matplotlib.cm.get_cmap`.
    """
    cmap = cm.get_cmap(cmap)

    rc('image', cmap=cmap.name)
    im = gci()

    if im is not None:
        im.set_cmap(cmap)

    draw_if_interactive() 

def cool():
    '''
    set the default colormap to cool and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='cool')
    im = gci()

    if im is not None:
        im.set_cmap(cm.cool)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def spy(
        Z, precision=0, marker=None, markersize=None, aspect='equal',
        origin='upper', **kwargs):
    __ret = gca().spy(
        Z, precision=precision, marker=marker, markersize=markersize,
        aspect=aspect, origin=origin, **kwargs)
    if isinstance(__ret, cm.ScalarMappable): sci(__ret)  # noqa
    return __ret


# Autogenerated by boilerplate.py.  Do not edit as changes will be lost. 

def copper():
    '''
    set the default colormap to copper and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='copper')
    im = gci()

    if im is not None:
        im.set_cmap(cm.copper)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def flag():
    '''
    set the default colormap to flag and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='flag')
    im = gci()

    if im is not None:
        im.set_cmap(cm.flag)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def gray():
    '''
    set the default colormap to gray and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='gray')
    im = gci()

    if im is not None:
        im.set_cmap(cm.gray)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def test_colormap_copy():
    cm = plt.cm.Reds
    cm_copy = copy.copy(cm)
    with np.errstate(invalid='ignore'):
        ret1 = cm_copy([-1, 0, .5, 1, np.nan, np.inf])
    cm2 = copy.copy(cm_copy)
    cm2.set_bad('g')
    with np.errstate(invalid='ignore'):
        ret2 = cm_copy([-1, 0, .5, 1, np.nan, np.inf])
    assert_array_equal(ret1, ret2) 

def test_colormap_endian():
    """
    Github issue #1005: a bug in putmask caused erroneous
    mapping of 1.0 when input from a non-native-byteorder
    array.
    """
    cmap = cm.get_cmap("jet")
    # Test under, over, and invalid along with values 0 and 1.
    a = [-0.5, 0, 0.5, 1, 1.5, np.nan]
    for dt in ["f2", "f4", "f8"]:
        anative = np.ma.masked_invalid(np.array(a, dtype=dt))
        aforeign = anative.byteswap().newbyteorder()
        assert_array_equal(cmap(anative), cmap(aforeign)) 

def spectral():
    '''
    set the default colormap to spectral and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='spectral')
    im = gci()

    if im is not None:
        im.set_cmap(cm.spectral)
    draw_if_interactive() 

def autumn():
    '''
    set the default colormap to autumn and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='autumn')
    im = gci()

    if im is not None:
        im.set_cmap(cm.autumn)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def gci():
    """
    Get the current colorable artist.  Specifically, returns the
    current :class:`~matplotlib.cm.ScalarMappable` instance (image or
    patch collection), or *None* if no images or patch collections
    have been defined.  The commands :func:`~matplotlib.pyplot.imshow`
    and :func:`~matplotlib.pyplot.figimage` create
    :class:`~matplotlib.image.Image` instances, and the commands
    :func:`~matplotlib.pyplot.pcolor` and
    :func:`~matplotlib.pyplot.scatter` create
    :class:`~matplotlib.collections.Collection` instances.  The
    current image is an attribute of the current axes, or the nearest
    earlier axes in the current figure that contains an image.
    """
    return gcf()._gci() 

def test_colorbarbase():
    # smoke test from #3805
    ax = plt.gca()
    ColorbarBase(ax, plt.cm.bone) 

def winter():
    '''
    set the default colormap to winter and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='winter')
    im = gci()

    if im is not None:
        im.set_cmap(cm.winter)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def summer():
    '''
    set the default colormap to summer and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='summer')
    im = gci()

    if im is not None:
        im.set_cmap(cm.summer)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def spring():
    '''
    set the default colormap to spring and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='spring')
    im = gci()

    if im is not None:
        im.set_cmap(cm.spring)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost 

def prism():
    '''
    set the default colormap to prism and apply to current image if any.
    See help(colormaps) for more information
    '''
    rc('image', cmap='prism')
    im = gci()

    if im is not None:
        im.set_cmap(cm.prism)
    draw_if_interactive()


# This function was autogenerated by boilerplate.py.  Do not edit as
# changes will be lost