.. _mplot3d-tricontour3d_demo:

mplot3d example code: tricontour3d_demo.py
==========================================



.. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/mplot3d/tricontour3d_demo.py

::

    """
    ==========================
    Triangular 3D contour plot
    ==========================
    
    Contour plots of unstructured triangular grids.
    
    The data used is the same as in the second plot of trisurf3d_demo2.
    tricontourf3d_demo shows the filled version of this example.
    """
    
    import matplotlib.pyplot as plt
    from mpl_toolkits.mplot3d import Axes3D
    import matplotlib.tri as tri
    import numpy as np
    
    n_angles = 48
    n_radii = 8
    min_radius = 0.25
    
    # Create the mesh in polar coordinates and compute x, y, z.
    radii = np.linspace(min_radius, 0.95, n_radii)
    angles = np.linspace(0, 2*np.pi, n_angles, endpoint=False)
    angles = np.repeat(angles[..., np.newaxis], n_radii, axis=1)
    angles[:, 1::2] += np.pi/n_angles
    
    x = (radii*np.cos(angles)).flatten()
    y = (radii*np.sin(angles)).flatten()
    z = (np.cos(radii)*np.cos(angles*3.0)).flatten()
    
    # Create a custom triangulation.
    triang = tri.Triangulation(x, y)
    
    # Mask off unwanted triangles.
    xmid = x[triang.triangles].mean(axis=1)
    ymid = y[triang.triangles].mean(axis=1)
    mask = np.where(xmid*xmid + ymid*ymid < min_radius*min_radius, 1, 0)
    triang.set_mask(mask)
    
    fig = plt.figure()
    ax = fig.gca(projection='3d')
    ax.tricontour(triang, z, cmap=plt.cm.CMRmap)
    
    # Customize the view angle so it's easier to understand the plot.
    ax.view_init(elev=45.)
    
    plt.show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)