#!/usr/bin/env python
from pylab import *
origin = 'lower'
#origin = 'upper'
# The following controls only interior masking.
test_masking = False # There is a bug in filled contour masking with
# interior masks.
if test_masking:
# Use a coarse grid so only a few masked points are needed.
delta = 0.5
else:
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)
# interior badmask doesn't work yet for filled contours
if test_masking:
badmask = zeros(shape(Z))
badmask[5,5] = 1
badmask[5,6] = 1
Z[5,5] = 0
Z[5,6] = 0
badmask[0,0] = 1
Z[0,0] = 0
Z = ma.array(Z, mask=badmask)
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
# 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.
CS2 = contour(X, Y, Z, CS.levels[::2],
colors = 'r',
origin=origin,
hold='on')
title('Nonsense (with 2 masked corners)')
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 = [-2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5]
CS3 = contourf(X, Y, Z, levels,
colors = ('r', 'g', 'b'),
origin=origin)
CS4 = contour(X, Y, Z, levels,
colors = ('k',),
linewidths = (3,),
origin = origin)
title('Listed colors (with 2 masked corners)')
clabel(CS4, fmt = '%2.1f', colors = 'w', fontsize=14)
colorbar(CS3)
show()
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