colormaps module

Module for commonly used colormaps and palettes for visualizing geospatial data.

create_colormap(cmap='gray', colors=None, discrete=False, label=None, width=8.0, height=0.4, orientation='horizontal', vmin=0, vmax=1.0, axis_off=False, show_name=False, font_size=12, **kwargs)

Plot a matplotlib colormap.

Parameters:

Name	Type	Description	Default
cmap	str	Matplotlib colormap. Defaults to "gray". See https://matplotlib.org/3.3.4/tutorials/colors/colormaps.html#sphx-glr-tutorials-colors-colormaps-py for options.	'gray'
colors	list	A list of custom colors to create a colormap. Defaults to None.	None
discrete	bool	Whether to create a discrete colorbar. Defaults to False.	False
label	str	Label for the colorbar. Defaults to None.	None
width	float	The width of the colormap. Defaults to 8.0.	8.0
height	float	The height of the colormap. Defaults to 0.4.	0.4
orientation	str	The orientation of the colormap. Defaults to "horizontal".	'horizontal'
vmin	float	The minimum value range. Defaults to 0.	0
vmax	float	The maximum value range. Defaults to 1.0.	1.0
axis_off	bool	Whether to turn axis off. Defaults to False.	False
show_name	bool	Whether to show the colormap name. Defaults to False.	False
font_size	int	Font size of the text. Defaults to 12.	12

Source code in leafmap/colormaps.py

def create_colormap(
    cmap: Optional[str] = "gray",
    colors: Optional[List] = None,
    discrete: Optional[bool] = False,
    label: Optional[str] = None,
    width: Optional[float] = 8.0,
    height: Optional[float] = 0.4,
    orientation: Optional[str] = "horizontal",
    vmin: Optional[float] = 0,
    vmax: Optional[float] = 1.0,
    axis_off: Optional[bool] = False,
    show_name: Optional[bool] = False,
    font_size: Optional[int] = 12,
    **kwargs
):
    """Plot a matplotlib colormap.

    Args:
        cmap (str, optional): Matplotlib colormap. Defaults to "gray". See https://matplotlib.org/3.3.4/tutorials/colors/colormaps.html#sphx-glr-tutorials-colors-colormaps-py for options.
        colors (list, optional): A list of custom colors to create a colormap. Defaults to None.
        discrete (bool, optional): Whether to create a discrete colorbar. Defaults to False.
        label (str, optional): Label for the colorbar. Defaults to None.
        width (float, optional): The width of the colormap. Defaults to 8.0.
        height (float, optional): The height of the colormap. Defaults to 0.4.
        orientation (str, optional): The orientation of the colormap. Defaults to "horizontal".
        vmin (float, optional): The minimum value range. Defaults to 0.
        vmax (float, optional): The maximum value range. Defaults to 1.0.
        axis_off (bool, optional): Whether to turn axis off. Defaults to False.
        show_name (bool, optional): Whether to show the colormap name. Defaults to False.
        font_size (int, optional): Font size of the text. Defaults to 12.
    """
    fig, ax = plt.subplots(figsize=(width, height))

    if colors is not None and (isinstance(colors, list) or isinstance(colors, tuple)):
        hexcodes = to_hex_colors(list(colors))
        if discrete:
            col_map = mpl.colors.ListedColormap(hexcodes)
            vals = np.linspace(vmin, vmax, col_map.N + 1)
            norm = mpl.colors.BoundaryNorm(vals, col_map.N)

        else:
            col_map = mpl.colors.LinearSegmentedColormap.from_list(
                "custom", hexcodes, N=256
            )
            norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)
    else:
        col_map = mpl.colormaps[cmap]
        norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)

    cb = mpl.colorbar.ColorbarBase(
        ax, norm=norm, cmap=col_map, orientation=orientation, **kwargs
    )

    if label is not None and isinstance(label, str):
        cb.set_label(label, fontsize=font_size)

    if axis_off:
        ax.set_axis_off()
    ax.tick_params(labelsize=font_size)

    if show_name:
        pos = list(ax.get_position().bounds)
        x_text = pos[0] - 0.01
        y_text = pos[1] + pos[3] / 2.0
        fig.text(x_text, y_text, cmap, va="center", ha="right", fontsize=font_size)

    return fig

get_colorbar(colors, vmin=0, vmax=1, width=6.0, height=0.4, orientation='horizontal', discrete=False)

Creates a colorbar based on custom colors.

Parameters:

Name	Type	Description	Default
colors	list	A list of hex colors.	required
vmin	float	The minimum value range. Defaults to 0.	0
vmax	float	The maximum value range. Defaults to 1.0.	1
width	float	The width of the colormap. Defaults to 6.0.	6.0
height	float	The height of the colormap. Defaults to 0.4.	0.4
orientation	str	The orientation of the colormap. Defaults to "horizontal".	'horizontal'
discrete	bool	Whether to create a discrete colormap.	False

Source code in leafmap/colormaps.py

def get_colorbar(
    colors: List,
    vmin: Optional[float] = 0,
    vmax: Optional[float] = 1,
    width: Optional[float] = 6.0,
    height: Optional[float] = 0.4,
    orientation: Optional[str] = "horizontal",
    discrete: Optional[bool] = False,
):
    """Creates a colorbar based on custom colors.

    Args:
        colors (list): A list of hex colors.
        vmin (float, optional): The minimum value range. Defaults to 0.
        vmax (float, optional): The maximum value range. Defaults to 1.0.
        width (float, optional): The width of the colormap. Defaults to 6.0.
        height (float, optional): The height of the colormap. Defaults to 0.4.
        orientation (str, optional): The orientation of the colormap. Defaults to "horizontal".
        discrete (bool, optional): Whether to create a discrete colormap.
    """
    hexcodes = [i if i[0] == "#" else "#" + i for i in colors]
    _, ax = plt.subplots(figsize=(width, height))
    if discrete:
        cmap = mpl.colors.ListedColormap(hexcodes)
        vals = np.linspace(vmin, vmax, cmap.N + 1)
        norm = mpl.colors.BoundaryNorm(vals, cmap.N)
    else:
        cmap = mpl.colors.LinearSegmentedColormap.from_list("custom", hexcodes, N=256)
        norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)
    mpl.colorbar.ColorbarBase(ax, norm=norm, cmap=cmap, orientation=orientation)
    plt.show()

get_palette(cmap_name=None, n_class=None, hashtag=False)

Get a palette from a matplotlib colormap. See the list of colormaps at https://matplotlib.org/stable/tutorials/colors/colormaps.html.

Parameters:

Name	Type	Description	Default
cmap_name	str	The name of the matplotlib colormap. Defaults to None.	None
n_class	int	The number of colors. Defaults to None.	None
hashtag	bool	Whether to return a list of hex colors. Defaults to False.	False

Returns:

Type	Description
list	A list of hex colors.

Source code in leafmap/colormaps.py

def get_palette(
    cmap_name: Optional[str] = None,
    n_class: Optional[int] = None,
    hashtag: Optional[bool] = False,
) -> List:
    """Get a palette from a matplotlib colormap. See the list of colormaps at https://matplotlib.org/stable/tutorials/colors/colormaps.html.

    Args:
        cmap_name (str, optional): The name of the matplotlib colormap. Defaults to None.
        n_class (int, optional): The number of colors. Defaults to None.
        hashtag (bool, optional): Whether to return a list of hex colors. Defaults to False.

    Returns:
        list: A list of hex colors.
    """

    if cmap_name in ["dem", "ndvi", "ndwi"]:
        colors = _palette_dict[cmap_name]
    else:
        cmap = mpl.colormaps[cmap_name]  # Retrieve colormap
        if n_class:
            colors = [
                mpl.colors.rgb2hex(cmap(i / (n_class - 1)))[1:] for i in range(n_class)
            ]
        else:
            colors = [mpl.colors.rgb2hex(cmap(i))[1:] for i in range(cmap.N)]
    if hashtag:
        colors = ["#" + i for i in colors]
    return colors

list_colormaps(add_extra=False, lowercase=False)

List all available colormaps. See a complete lost of colormaps at https://matplotlib.org/stable/tutorials/colors/colormaps.html.

Returns:

Type	Description
list	The list of colormap names.

Source code in leafmap/colormaps.py

def list_colormaps(add_extra: bool = False, lowercase: bool = False) -> List:
    """List all available colormaps. See a complete lost of colormaps at https://matplotlib.org/stable/tutorials/colors/colormaps.html.

    Returns:
        list: The list of colormap names.
    """
    result = plt.colormaps()
    if add_extra:
        result += ["dem", "ndvi", "ndwi"]
    if lowercase:
        result = [i.lower() for i in result]
    result.sort()
    return result

plot_colormap(cmap='gray', colors=None, discrete=False, label=None, width=8.0, height=0.4, orientation='horizontal', vmin=0, vmax=1.0, axis_off=False, show_name=False, font_size=12, **kwargs)

Plot a matplotlib colormap.

Parameters:

Name	Type	Description	Default
cmap	str	Matplotlib colormap. Defaults to "gray". See https://matplotlib.org/3.3.4/tutorials/colors/colormaps.html#sphx-glr-tutorials-colors-colormaps-py for options.	'gray'
colors	list	A list of custom colors to create a colormap. Defaults to None.	None
discrete	bool	Whether to create a discrete colorbar. Defaults to False.	False
label	str	Label for the colorbar. Defaults to None.	None
width	float	The width of the colormap. Defaults to 8.0.	8.0
height	float	The height of the colormap. Defaults to 0.4.	0.4
orientation	str	The orientation of the colormap. Defaults to "horizontal".	'horizontal'
vmin	float	The minimum value range. Defaults to 0.	0
vmax	float	The maximum value range. Defaults to 1.0.	1.0
axis_off	bool	Whether to turn axis off. Defaults to False.	False
show_name	bool	Whether to show the colormap name. Defaults to False.	False
font_size	int	Font size of the text. Defaults to 12.	12

Source code in leafmap/colormaps.py

def plot_colormap(
    cmap: Optional[str] = "gray",
    colors: Optional[List] = None,
    discrete: Optional[bool] = False,
    label: Optional[str] = None,
    width: Optional[float] = 8.0,
    height: Optional[float] = 0.4,
    orientation: Optional[str] = "horizontal",
    vmin: Optional[float] = 0,
    vmax: Optional[float] = 1.0,
    axis_off: Optional[bool] = False,
    show_name: Optional[bool] = False,
    font_size: Optional[int] = 12,
    **kwargs
):
    """Plot a matplotlib colormap.

    Args:
        cmap (str, optional): Matplotlib colormap. Defaults to "gray". See https://matplotlib.org/3.3.4/tutorials/colors/colormaps.html#sphx-glr-tutorials-colors-colormaps-py for options.
        colors (list, optional): A list of custom colors to create a colormap. Defaults to None.
        discrete (bool, optional): Whether to create a discrete colorbar. Defaults to False.
        label (str, optional): Label for the colorbar. Defaults to None.
        width (float, optional): The width of the colormap. Defaults to 8.0.
        height (float, optional): The height of the colormap. Defaults to 0.4.
        orientation (str, optional): The orientation of the colormap. Defaults to "horizontal".
        vmin (float, optional): The minimum value range. Defaults to 0.
        vmax (float, optional): The maximum value range. Defaults to 1.0.
        axis_off (bool, optional): Whether to turn axis off. Defaults to False.
        show_name (bool, optional): Whether to show the colormap name. Defaults to False.
        font_size (int, optional): Font size of the text. Defaults to 12.
    """
    fig, ax = plt.subplots(figsize=(width, height))

    if colors is not None and (isinstance(colors, list) or isinstance(colors, tuple)):
        hexcodes = to_hex_colors(list(colors))
        if discrete:
            col_map = mpl.colors.ListedColormap(hexcodes)
            vals = np.linspace(vmin, vmax, col_map.N + 1)
            norm = mpl.colors.BoundaryNorm(vals, col_map.N)

        else:
            col_map = mpl.colors.LinearSegmentedColormap.from_list(
                "custom", hexcodes, N=256
            )
            norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)
    else:
        col_map = mpl.colormaps[cmap]
        norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)

    cb = mpl.colorbar.ColorbarBase(
        ax, norm=norm, cmap=col_map, orientation=orientation, **kwargs
    )

    if label is not None and isinstance(label, str):
        cb.set_label(label, fontsize=font_size)

    if axis_off:
        ax.set_axis_off()
    ax.tick_params(labelsize=font_size)

    if show_name:
        pos = list(ax.get_position().bounds)
        x_text = pos[0] - 0.01
        y_text = pos[1] + pos[3] / 2.0
        fig.text(x_text, y_text, cmap, va="center", ha="right", fontsize=font_size)

    plt.show()

plot_colormaps(width=8.0, height=0.4, return_fig=False, **kwargs)

Plot all available colormaps.

Parameters:

Name	Type	Description	Default
width	float	Width of the colormap. Defaults to 8.0.	8.0
height	float	Height of the colormap. Defaults to 0.4.	0.4
return_fig	bool	Whether to return the figure. Defaults to False.	False

Source code in leafmap/colormaps.py

def plot_colormaps(
    width: Optional[float] = 8.0,
    height: Optional[float] = 0.4,
    return_fig: Optional[bool] = False,
    **kwargs
):
    """Plot all available colormaps.

    Args:
        width (float, optional): Width of the colormap. Defaults to 8.0.
        height (float, optional): Height of the colormap. Defaults to 0.4.
        return_fig (bool, optional): Whether to return the figure. Defaults to False.
    """
    cmap_list = list_colormaps()
    nrows = len(cmap_list)
    fig, axes = plt.subplots(nrows=nrows, figsize=(width, height * nrows))
    fig.subplots_adjust(top=0.95, bottom=0.01, left=0.2, right=0.99)

    gradient = np.linspace(0, 1, 256)
    gradient = np.vstack((gradient, gradient))

    for ax, name in zip(axes, cmap_list):
        ax.imshow(gradient, aspect="auto", cmap=mpl.colormaps[name])
        ax.set_axis_off()
        pos = list(ax.get_position().bounds)
        x_text = pos[0] - 0.01
        y_text = pos[1] + pos[3] / 2.0
        fig.text(x_text, y_text, name, va="center", ha="right", fontsize=12)

    # Turn off *all* ticks & spines, not just the ones with colormaps.
    for ax in axes:
        ax.set_axis_off()

    if return_fig:
        return fig
    else:
        plt.show()