.. _pylab_examples-tricontour_smooth_user: pylab_examples example code: tricontour_smooth_user.py ====================================================== .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/pylab_examples/tricontour_smooth_user.py :: """ Demonstrates high-resolution tricontouring on user-defined triangular grids with matplotlib.tri.UniformTriRefiner """ import matplotlib.tri as tri import matplotlib.pyplot as plt import matplotlib.cm as cm import numpy as np import math #----------------------------------------------------------------------------- # Analytical test function #----------------------------------------------------------------------------- def function_z(x, y): """ A function of 2 variables """ r1 = np.sqrt((0.5 - x)**2 + (0.5 - y)**2) theta1 = np.arctan2(0.5 - x, 0.5 - y) r2 = np.sqrt((-x - 0.2)**2 + (-y - 0.2)**2) theta2 = np.arctan2(-x - 0.2, -y - 0.2) z = -(2*(np.exp((r1/10)**2) - 1)*30. * np.cos(7.*theta1) + (np.exp((r2/10)**2) - 1)*30. * np.cos(11.*theta2) + 0.7*(x**2 + y**2)) return (np.max(z) - z)/(np.max(z) - np.min(z)) #----------------------------------------------------------------------------- # Creating a Triangulation #----------------------------------------------------------------------------- # First create the x and y coordinates of the points. n_angles = 20 n_radii = 10 min_radius = 0.15 radii = np.linspace(min_radius, 0.95, n_radii) angles = np.linspace(0, 2*math.pi, n_angles, endpoint=False) angles = np.repeat(angles[..., np.newaxis], n_radii, axis=1) angles[:, 1::2] += math.pi/n_angles x = (radii*np.cos(angles)).flatten() y = (radii*np.sin(angles)).flatten() z = function_z(x, y) # Now create the Triangulation. # (Creating a Triangulation without specifying the triangles results in the # Delaunay triangulation of the points.) 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) #----------------------------------------------------------------------------- # Refine data #----------------------------------------------------------------------------- refiner = tri.UniformTriRefiner(triang) tri_refi, z_test_refi = refiner.refine_field(z, subdiv=3) #----------------------------------------------------------------------------- # Plot the triangulation and the high-res iso-contours #----------------------------------------------------------------------------- plt.figure() plt.gca().set_aspect('equal') plt.triplot(triang, lw=0.5, color='white') levels = np.arange(0., 1., 0.025) cmap = cm.get_cmap(name='terrain', lut=None) plt.tricontourf(tri_refi, z_test_refi, levels=levels, cmap=cmap) plt.tricontour(tri_refi, z_test_refi, levels=levels, colors=['0.25', '0.5', '0.5', '0.5', '0.5'], linewidths=[1.0, 0.5, 0.5, 0.5, 0.5]) plt.title("High-resolution tricontouring") plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)