.. _pylab_examples-pcolor_demo: pylab_examples example code: pcolor_demo.py =========================================== .. plot:: /home/tcaswell/src/p/matplotlib/doc/mpl_examples/pylab_examples/pcolor_demo.py :: """ Demonstrates similarities between pcolor, pcolormesh, imshow and pcolorfast for drawing quadrilateral grids. """ import matplotlib.pyplot as plt import numpy as np # make these smaller to increase the resolution dx, dy = 0.15, 0.05 # generate 2 2d grids for the x & y bounds y, x = np.mgrid[slice(-3, 3 + dy, dy), slice(-3, 3 + dx, dx)] z = (1 - x / 2. + x ** 5 + y ** 3) * np.exp(-x ** 2 - y ** 2) # x and y are bounds, so z should be the value *inside* those bounds. # Therefore, remove the last value from the z array. z = z[:-1, :-1] z_min, z_max = -np.abs(z).max(), np.abs(z).max() plt.subplot(2, 2, 1) plt.pcolor(x, y, z, cmap='RdBu', vmin=z_min, vmax=z_max) plt.title('pcolor') # set the limits of the plot to the limits of the data plt.axis([x.min(), x.max(), y.min(), y.max()]) plt.colorbar() plt.subplot(2, 2, 2) plt.pcolormesh(x, y, z, cmap='RdBu', vmin=z_min, vmax=z_max) plt.title('pcolormesh') # set the limits of the plot to the limits of the data plt.axis([x.min(), x.max(), y.min(), y.max()]) plt.colorbar() plt.subplot(2, 2, 3) plt.imshow(z, cmap='RdBu', vmin=z_min, vmax=z_max, extent=[x.min(), x.max(), y.min(), y.max()], interpolation='nearest', origin='lower') plt.title('image (nearest)') plt.colorbar() ax = plt.subplot(2, 2, 4) ax.pcolorfast(x, y, z, cmap='RdBu', vmin=z_min, vmax=z_max) plt.title('pcolorfast') plt.colorbar() plt.subplots_adjust(wspace=0.5, hspace=0.5) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)