Introduction
This tutorial will demonstrate how to create a grid of images using Matplotlib's ImageGrid. We will create a 2x2 grid of images and explore various ways to add colorbars to the grid.
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Import necessary libraries and data
We first need to import the necessary libraries and data to create our grid. We will use matplotlib.pyplot for plotting, cbook to get a sample data set, and ImageGrid to create our grid.
import matplotlib.pyplot as plt
from matplotlib import cbook
from mpl_toolkits.axes_grid1 import ImageGrid
# Get sample data
Z = cbook.get_sample_data("axes_grid/bivariate_normal.npy") # 15x15 array
extent = (-3, 4, -4, 3)
Create a grid of 2x2 images with a single colorbar
Our first grid will be a 2x2 grid of images with a single colorbar. We will use the ImageGrid function to create the grid and specify the number of rows and columns we want. We will also specify the location of the colorbar and set share_all to True to share the colorbar across all images.
# Create a grid of 2x2 images with a single colorbar
grid = ImageGrid(
fig, # Figure object
141, # Location of subplot
nrows_ncols=(2, 2), # Number of rows and columns
axes_pad=0.0, # Padding between axes
label_mode="L", # Label mode
share_all=True, # Share colorbar across all images
cbar_location="top", # Location of colorbar
cbar_mode="single" # Colorbar mode
)
# Plot images on grid
for ax in grid:
im = ax.imshow(Z, extent=extent)
# Add colorbar to grid
grid.cbar_axes[0].colorbar(im)
for cax in grid.cbar_axes:
cax.tick_params(labeltop=False)
Create a grid of 2x2 images with each image having its own colorbar
Our next grid will be a 2x2 grid of images with each image having its own colorbar. We will use the ImageGrid function again, but this time we will set cbar_mode to "each" to specify that each image should have its own colorbar.
# Create a grid of 2x2 images with each image having its own colorbar
grid = ImageGrid(
fig, # Figure object
142, # Location of subplot
nrows_ncols=(2, 2), # Number of rows and columns
axes_pad=0.1, # Padding between axes
label_mode="1", # Label mode
share_all=True, # Share colorbar across all images
cbar_location="top", # Location of colorbar
cbar_mode="each", # Colorbar mode
cbar_size="7%", # Size of colorbar
cbar_pad="2%" # Padding between colorbar and images
)
# Plot images on grid and add colorbars
for ax, cax in zip(grid, grid.cbar_axes):
im = ax.imshow(Z, extent=extent)
cax.colorbar(im)
cax.tick_params(labeltop=False)
Create a grid of 2x2 images with each image having its own colorbar and a different colorbar range
Our final grid will also be a 2x2 grid of images with each image having its own colorbar, but this time we will use a different colorbar range for each image. We will set the colorbar range using vmin and vmax when plotting each image.
# Create a grid of 2x2 images with each image having its own colorbar and a different colorbar range
grid = ImageGrid(
fig, # Figure object
143, # Location of subplot
nrows_ncols=(2, 2), # Number of rows and columns
axes_pad=(0.45, 0.15), # Padding between axes
label_mode="1", # Label mode
share_all=True, # Share colorbar across all images
cbar_location="right", # Location of colorbar
cbar_mode="each", # Colorbar mode
cbar_size="7%", # Size of colorbar
cbar_pad="2%" # Padding between colorbar and images
)
# Plot images on grid and add colorbars
limits = ((0, 1), (-2, 2), (-1.7, 1.4), (-1.5, 1)) # Different colorbar ranges
for ax, cax, vlim in zip(grid, grid.cbar_axes, limits):
im = ax.imshow(Z, extent=extent, vmin=vlim[0], vmax=vlim[1])
cb = cax.colorbar(im)
cb.set_ticks((vlim[0], vlim[1]))
Summary
In this tutorial, we learned how to create a grid of images using Matplotlib's ImageGrid. We explored different ways to add colorbars to the grid, including using a single colorbar for all images, giving each image its own colorbar, and giving each image its own colorbar with a different colorbar range.
🚀 Practice Now: Create Image Grid with Matplotlib
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