#!/usr/bin/env python from pylab import * origin = 'lower' #origin = 'upper' delta = 0.025 x = y = arange(-3.0, 3.01, delta) X, Y = meshgrid(x, y) Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0) Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1) Z = 10 * (Z1 - Z2) nr, nc = Z.shape # put NaNs in one corner: Z[-nr//6:, -nc//6:] = nan # contourf will convert these to masked Z = ma.array(Z) # mask another corner: Z[:nr//6, :nc//6] = ma.masked # mask a circle in the middle: interior = sqrt((X**2) + (Y**2)) < 0.5 Z[interior] = ma.masked # We are using automatic selection of contour levels; # this is usually not such a good idea, because they don't # occur on nice boundaries, but we do it here for purposes # of illustration. CS = contourf(X, Y, Z, 10, # [-1, -0.1, 0, 0.1], #alpha=0.5, cmap=cm.bone, origin=origin) # Note that in the following, we explicitly pass in a subset of # the contour levels used for the filled contours. Alternatively, # We could pass in additional levels to provide extra resolution, # or leave out the levels kwarg to use all of the original levels. CS2 = contour(CS, levels=CS.levels[::2], colors = 'r', origin=origin, hold='on') title('Nonsense (3 masked regions)') xlabel('word length anomaly') ylabel('sentence length anomaly') # Make a colorbar for the ContourSet returned by the contourf call. cbar = colorbar(CS) cbar.ax.set_ylabel('verbosity coefficient') # Add the contour line levels to the colorbar cbar.add_lines(CS2) figure() # Now make a contour plot with the levels specified, # and with the colormap generated automatically from a list # of colors. levels = [-1.5, -1, -0.5, 0, 0.5, 1] CS3 = contourf(X, Y, Z, levels, colors = ('r', 'g', 'b'), origin=origin, extend='both') # Our data range extends outside the range of levels; make # data below the lowest contour level yellow, and above the # highest level cyan: CS3.cmap.set_under('yellow') CS3.cmap.set_over('cyan') CS4 = contour(X, Y, Z, levels, colors = ('k',), linewidths = (3,), origin = origin) title('Listed colors (3 masked regions)') clabel(CS4, fmt = '%2.1f', colors = 'w', fontsize=14) # Notice that the colorbar command gets all the information it # needs from the ContourSet object, CS3. colorbar(CS3) show()