colormaps module

Module for commonly used colormaps and palettes for visualizing Earth Engine data.

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

Creates a colorbar based on custom colors.

Parameters:

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

Source code in geemap/colormaps.py

def get_colorbar(
    colors: list[str],
    vmin: float = 0,
    vmax: float = 1,
    width: float = 6.0,
    height: float = 0.4,
    orientation: str = "horizontal",
    discrete: bool = False,
    return_fig: bool = False,
) -> mpl.figure.Figure | None:
    """Creates a colorbar based on custom colors.

    Args:
        colors: A list of hex colors.
        vmin: The minimum value range.
        vmax: The maximum value range.
        width: The width of the colormap.
        height: The height of the colormap.
        orientation: The orientation of the colormap.
        discrete: Whether to create a discrete colormap.
        return_fig: Whether to return the figure.
    """
    hexcodes = [i if i[0] == "#" else "#" + i for i in colors]
    fig, 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)

    if return_fig:
        return fig

    plt.show()

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

Returns a palette of hex colors from a matplotlib colormap.

WARNING: This function is inconsistent with how it handles hashes in the color names w.r.t. if there is a leading hash (#).

See the list of colormaps at https://matplotlib.org/stable/tutorials/colors/colormaps.html.

Parameters:

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

Source code in geemap/colormaps.py

def get_palette(
    cmap_name: str | None = None, n_class: int | None = None, hashtag: bool = False
) -> Any:
    """Returns a palette of hex colors from a matplotlib colormap.

    WARNING: This function is inconsistent with how it handles hashes in the
    color names w.r.t. if there is a leading hash (`#`).

    See the list of colormaps at
    https://matplotlib.org/stable/tutorials/colors/colormaps.html.

    Args:
        cmap_name: The name of the matplotlib colormap.
        n_class: The number of colors.
        hashtag: Whether to return a list of hex colors.
    """
    if cmap_name in ["ndvi", "ndwi", "dem", "dw", "esri_lulc"]:
        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)]

    def add_hashtag(color: str) -> str:
        if color.startswith("#"):
            return color

        return f"#{color}"

    if hashtag:
        colors = [add_hashtag(color) for color in colors]

    return colors

get_palettes()

Returns a dictionary of colormaps and their associated palettes.

Source code in geemap/colormaps.py

def get_palettes() -> box.Box:
    """Returns a dictionary of colormaps and their associated palettes."""
    for cmap_name in list_colormaps():
        color_dict = {}
        color_dict["default"] = get_palette(cmap_name)
        for i in range(3, 13):
            name = "n" + str(i).zfill(2)
            colors = get_palette(cmap_name, i)
            color_dict[name] = colors
        _palette_dict[cmap_name] = color_dict

    return box.Box(_palette_dict, frozen_box=True)

list_colormaps(add_extra=False, lowercase=False)

Returns a list of all the available colormap names.

See a complete lost of colormaps:

https://matplotlib.org/stable/tutorials/colors/colormaps.html

Source code in geemap/colormaps.py

def list_colormaps(add_extra: bool = False, lowercase: bool = False) -> list[str]:
    """Returns a list of all the available colormap names.

    See a complete lost of colormaps:

        https://matplotlib.org/stable/tutorials/colors/colormaps.html
    """
    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, width=8.0, height=0.4, orientation='horizontal', vmin=0, vmax=1.0, axis_off=True, show_name=False, font_size=12, return_fig=False)

Plot a matplotlib colormap.

Parameters:

Name	Type	Description	Default
cmap	str	The name of the colormap.	required
width	float	The width of the colormap.	8.0
height	float	The height of the colormap.	0.4
orientation	str	The orientation of the colormap.	'horizontal'
vmin	float	The minimum value range.	0
vmax	float	The maximum value range.	1.0
axis_off	bool	Whether to turn axis off.	True
show_name	bool	Whether to show the colormap name.	False
font_size	int	Font size of the text.	12
return_fig	bool	Whether to return the figure.	False

Source code in geemap/colormaps.py

def plot_colormap(
    cmap: str,
    width: float = 8.0,
    height: float = 0.4,
    orientation: str = "horizontal",
    vmin: float = 0,
    vmax: float = 1.0,
    axis_off: bool = True,
    show_name: bool = False,
    font_size: int = 12,
    return_fig: bool = False,
) -> mpl.figure.Figure | None:
    """Plot a matplotlib colormap.

    Args:
        cmap: The name of the colormap.
        width: The width of the colormap.
        height: The height of the colormap.
        orientation: The orientation of the colormap.
        vmin: The minimum value range.
        vmax: The maximum value range.
        axis_off: Whether to turn axis off.
        show_name: Whether to show the colormap name.
        font_size: Font size of the text.
        return_fig: Whether to return the figure.
    """
    fig, ax = plt.subplots(figsize=(width, height))
    col_map = mpl.colormaps[cmap]

    norm = mpl.colors.Normalize(vmin=vmin, vmax=vmax)

    mpl.colorbar.ColorbarBase(ax, norm=norm, cmap=col_map, orientation=orientation)
    if axis_off:
        ax.set_axis_off()

    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)

    if return_fig:
        return fig

    plt.show()

plot_colormaps(width=8.0, height=0.4)

Plot all available colormaps.

Parameters:

Name	Type	Description	Default
width	float	Width of the colormap.	8.0
height	float	Height of the colormap.	0.4

Source code in geemap/colormaps.py

def plot_colormaps(width: float = 8.0, height: float = 0.4) -> None:
    """Plot all available colormaps.

    Args:
        width: Width of the colormap.
        height: Height of the colormap.
    """
    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()

    plt.show()