.. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_images_contours_and_fields_quadmesh_demo.py: ============= QuadMesh Demo ============= pcolormesh uses a QuadMesh, a faster generalization of pcolor, but with some restrictions. This demo illustrates a bug in quadmesh with masked data. .. image:: /gallery/images_contours_and_fields/images/sphx_glr_quadmesh_demo_001.png :class: sphx-glr-single-img .. code-block:: python import copy from matplotlib import cm, colors, pyplot as plt import numpy as np n = 12 x = np.linspace(-1.5, 1.5, n) y = np.linspace(-1.5, 1.5, n * 2) X, Y = np.meshgrid(x, y) Qx = np.cos(Y) - np.cos(X) Qz = np.sin(Y) + np.sin(X) Z = np.sqrt(X**2 + Y**2) / 5 Z = (Z - Z.min()) / (Z.max() - Z.min()) # The color array can include masked values. Zm = np.ma.masked_where(np.abs(Qz) < 0.5 * np.max(Qz), Z) fig, axs = plt.subplots(1, 3) axs[0].pcolormesh(Qx, Qz, Z, shading='gouraud') axs[0].set_title('Without masked values') # You can control the color of the masked region. We copy the default colormap # before modifying it. cmap = copy.copy(cm.get_cmap(plt.rcParams['image.cmap'])) cmap.set_bad('y', 1.0) axs[1].pcolormesh(Qx, Qz, Zm, shading='gouraud', cmap=cmap) axs[1].set_title('With masked values') # Or use the default, which is transparent. axs[2].pcolormesh(Qx, Qz, Zm, shading='gouraud') axs[2].set_title('With masked values') fig.tight_layout() plt.show() .. _sphx_glr_download_gallery_images_contours_and_fields_quadmesh_demo.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: quadmesh_demo.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: quadmesh_demo.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_