#!/usr/bin/env python
'''
Illustrate simple contour plotting, contours on an image with
a colorbar for the contours, and labelled contours.
See also contour_image.py.
'''
from pylab import *
rcParams['xtick.direction'] = 'out'
rcParams['ytick.direction'] = 'out'
delta = 0.025
x = arange(-3.0, 3.0, delta)
y = arange(-2.0, 2.0, 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)
# difference of Gaussians
Z = 10.0 * (Z2 - Z1)
# Create a simple contour plot with labels using default colors. The
# inline argument to clabel will control whether the labels are draw
# over the line segments of the contour, removing the lines beneath
# the label
figure()
CS = contour(X, Y, Z)
clabel(CS, inline=1, fontsize=10)
title('Simplest default with labels')
# You can force all the contours to be the same color.
figure()
CS = contour(X, Y, Z, 6,
colors='k', # negative contours will be dashed by default
)
clabel(CS, fontsize=9, inline=1)
title('Single color - negative contours dashed')
# You can set the dash pattern for negative contours
# (default is dashed). Specified as (on, off) in pixels.
# Making the second element of the tuple zero yields solid lines.
rcParams['contour.negative_linestyle'] = (6,0)
figure()
CS = contour(X, Y, Z, 6,
colors='k', # negative contours will be dashed by default
)
clabel(CS, fontsize=9, inline=1)
title('Single color - negative contours solid')
# And you can manually specify the colors of the contour
figure()
CS = contour(X, Y, Z, 6,
linewidths=arange(.5, 4, .5),
colors=('r', 'green', 'blue', (1,1,0), '#afeeee', '0.5')
)
clabel(CS, fontsize=9, inline=1)
title('Crazy lines')
# Or you can use a colormap to specify the colors; the default
# colormap will be used for the contour lines
figure()
im = imshow(Z, interpolation='bilinear', origin='lower',
cmap=cm.gray, extent=(-3,3,-2,2))
levels = arange(-1.2, 1.6, 0.2)
CS = contour(Z, levels,
origin='lower',
linewidths=2,
extent=(-3,3,-2,2))
#Thicken the zero contour.
zc = CS.collections[6]
setp(zc, linewidth=4)
clabel(CS, levels[1::2], # label every second level
inline=1,
fmt='%1.1f',
fontsize=14)
# make a colorbar for the contour lines
CB = colorbar(CS, shrink=0.8, extend='both')
title('Lines with colorbar')
hot() # Now change the colormap for the contour lines and colorbar
flag()
# We can still add a colorbar for the image, too.
CBI = colorbar(im, orientation='horizontal', shrink=0.8)
# This makes the original colorbar look a bit out of place,
# so let's improve its position.
l,b,w,h = gca().get_position()
ll,bb,ww,hh = CB.ax.get_position()
CB.ax.set_position([ll, b+0.1*h, ww, h*0.8])
savefig('contour_demo')
show()
