axes_grid example code: demo_axes_grid2.py

(Source code, png)

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import ImageGrid
import numpy as np


def get_demo_image():
    from matplotlib.cbook import get_sample_data
    f = get_sample_data("axes_grid/bivariate_normal.npy", asfileobj=False)
    z = np.load(f)
    # z is a numpy array of 15x15
    return z, (-3, 4, -4, 3)


def add_inner_title(ax, title, loc, size=None, **kwargs):
    from matplotlib.offsetbox import AnchoredText
    from matplotlib.patheffects import withStroke
    if size is None:
        size = dict(size=plt.rcParams['legend.fontsize'])
    at = AnchoredText(title, loc=loc, prop=size,
                      pad=0., borderpad=0.5,
                      frameon=False, **kwargs)
    ax.add_artist(at)
    at.txt._text.set_path_effects([withStroke(foreground="w", linewidth=3)])
    return at

if 1:
    F = plt.figure(1, (6, 6))
    F.clf()

    # prepare images
    Z, extent = get_demo_image()
    ZS = [Z[i::3, :] for i in range(3)]
    extent = extent[0], extent[1]/3., extent[2], extent[3]

    # demo 1 : colorbar at each axes

    grid = ImageGrid(F, 211,  # similar to subplot(111)
                     nrows_ncols=(1, 3),
                     direction="row",
                     axes_pad = 0.05,
                     add_all=True,
                     label_mode = "1",
                     share_all = True,
                     cbar_location="top",
                     cbar_mode="each",
                     cbar_size="7%",
                     cbar_pad="1%",
                     )

    for ax, z in zip(grid, ZS):
        im = ax.imshow(
            z, origin="lower", extent=extent, interpolation="nearest")
        ax.cax.colorbar(im)

    for ax, im_title in zip(grid, ["Image 1", "Image 2", "Image 3"]):
        t = add_inner_title(ax, im_title, loc=3)
        t.patch.set_alpha(0.5)

    for ax, z in zip(grid, ZS):
        ax.cax.toggle_label(True)
        #axis = ax.cax.axis[ax.cax.orientation]
        #axis.label.set_text("counts s$^{-1}$")
        #axis.label.set_size(10)
        #axis.major_ticklabels.set_size(6)

    # changing the colorbar ticks
    grid[1].cax.set_xticks([-1, 0, 1])
    grid[2].cax.set_xticks([-1, 0, 1])

    grid[0].set_xticks([-2, 0])
    grid[0].set_yticks([-2, 0, 2])

    # demo 2 : shared colorbar

    grid2 = ImageGrid(F, 212,
                      nrows_ncols=(1, 3),
                      direction="row",
                      axes_pad = 0.05,
                      add_all=True,
                      label_mode = "1",
                      share_all = True,
                      cbar_location="right",
                      cbar_mode="single",
                      cbar_size="10%",
                      cbar_pad=0.05,
                      )

    grid2[0].set_xlabel("X")
    grid2[0].set_ylabel("Y")

    vmax, vmin = np.max(ZS), np.min(ZS)
    import matplotlib.colors
    norm = matplotlib.colors.Normalize(vmax=vmax, vmin=vmin)

    for ax, z in zip(grid2, ZS):
        im = ax.imshow(z, norm=norm,
                       origin="lower", extent=extent,
                       interpolation="nearest")

    # With cbar_mode="single", cax attribute of all axes are identical.
    ax.cax.colorbar(im)
    ax.cax.toggle_label(True)

    for ax, im_title in zip(grid2, ["(a)", "(b)", "(c)"]):
        t = add_inner_title(ax, im_title, loc=2)
        t.patch.set_ec("none")
        t.patch.set_alpha(0.5)

    grid2[0].set_xticks([-2, 0])
    grid2[0].set_yticks([-2, 0, 2])

    plt.draw()
    plt.show()

Keywords: python, matplotlib, pylab, example, codex (see Search examples)