<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>pylab_examples example code: contour_demo.py — Matplotlib v1.1.1 documentation</title> <link rel="stylesheet" href="../../_static/mpl.css" type="text/css" /> <link rel="stylesheet" href="../../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../', VERSION: '1.1.1', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../_static/jquery.js"></script> <script type="text/javascript" src="../../_static/underscore.js"></script> <script type="text/javascript" src="../../_static/doctools.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Matplotlib v1.1.1 documentation" href="../../_static/opensearch.xml"/> <link rel="top" title="Matplotlib v1.1.1 documentation" href="../../index.html" /> </head> <body> <!-- Piwik --> <script type="text/javascript"> if ("matplotlib.sourceforge.net" == document.location.hostname || "matplotlib.sf.net" == document.location.hostname) { var pkBaseURL = (("https:" == document.location.protocol) ? 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<input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="pylab-examples-example-code-contour-demo-py"> <span id="pylab-examples-contour-demo"></span><h1>pylab_examples example code: contour_demo.py<a class="headerlink" href="#pylab-examples-example-code-contour-demo-py" title="Permalink to this headline">ΒΆ</a></h1> <p>(<a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo.py">Source code</a>)</p> <div class="figure"> <img alt="../../_images/contour_demo_00.png" src="../../_images/contour_demo_00.png" /> <p class="caption">(<a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_00.png">png</a>, <a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_00.hires.png">hires.png</a>, <a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_00.pdf">pdf</a>)</p> </div> <div class="figure"> <img alt="../../_images/contour_demo_01.png" src="../../_images/contour_demo_01.png" /> <p class="caption">(<a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_01.png">png</a>, <a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_01.hires.png">hires.png</a>, <a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_01.pdf">pdf</a>)</p> </div> <div class="figure"> <img alt="../../_images/contour_demo_02.png" src="../../_images/contour_demo_02.png" /> <p class="caption">(<a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_02.png">png</a>, <a class="reference external" href="../../mpl_examples/pylab_examples/contour_demo_02.hires.png">hires.png</a>, <a 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href="../../mpl_examples/pylab_examples/contour_demo_04.pdf">pdf</a>)</p> </div> <div class="highlight-python"><div class="highlight"><pre><span class="c">#!/usr/bin/env python</span> <span class="sd">"""</span> <span class="sd">Illustrate simple contour plotting, contours on an image with</span> <span class="sd">a colorbar for the contours, and labelled contours.</span> <span class="sd">See also contour_image.py.</span> <span class="sd">"""</span> <span class="kn">import</span> <span class="nn">matplotlib</span> <span class="kn">import</span> <span class="nn">numpy</span> <span class="kn">as</span> <span class="nn">np</span> <span class="kn">import</span> <span class="nn">matplotlib.cm</span> <span class="kn">as</span> <span class="nn">cm</span> <span class="kn">import</span> <span class="nn">matplotlib.mlab</span> <span class="kn">as</span> <span class="nn">mlab</span> <span class="kn">import</span> <span class="nn">matplotlib.pyplot</span> <span class="kn">as</span> <span class="nn">plt</span> <span class="n">matplotlib</span><span class="o">.</span><span class="n">rcParams</span><span class="p">[</span><span class="s">'xtick.direction'</span><span class="p">]</span> <span class="o">=</span> <span class="s">'out'</span> <span class="n">matplotlib</span><span class="o">.</span><span class="n">rcParams</span><span class="p">[</span><span class="s">'ytick.direction'</span><span class="p">]</span> <span class="o">=</span> <span class="s">'out'</span> <span class="n">delta</span> <span class="o">=</span> <span class="mf">0.025</span> <span class="n">x</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="o">-</span><span class="mf">3.0</span><span class="p">,</span> <span class="mf">3.0</span><span class="p">,</span> <span class="n">delta</span><span class="p">)</span> <span class="n">y</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="o">-</span><span class="mf">2.0</span><span class="p">,</span> <span class="mf">2.0</span><span class="p">,</span> <span class="n">delta</span><span class="p">)</span> <span class="n">X</span><span class="p">,</span> <span class="n">Y</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">meshgrid</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">)</span> <span class="n">Z1</span> <span class="o">=</span> <span class="n">mlab</span><span class="o">.</span><span class="n">bivariate_normal</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="mf">1.0</span><span class="p">,</span> <span class="mf">1.0</span><span class="p">,</span> <span class="mf">0.0</span><span class="p">,</span> <span class="mf">0.0</span><span class="p">)</span> <span class="n">Z2</span> <span class="o">=</span> <span class="n">mlab</span><span class="o">.</span><span class="n">bivariate_normal</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="mf">1.5</span><span class="p">,</span> <span class="mf">0.5</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span> <span class="c"># difference of Gaussians</span> <span class="n">Z</span> <span class="o">=</span> <span class="mf">10.0</span> <span class="o">*</span> <span class="p">(</span><span class="n">Z2</span> <span class="o">-</span> <span class="n">Z1</span><span class="p">)</span> <span class="c"># Create a simple contour plot with labels using default colors. The</span> <span class="c"># inline argument to clabel will control whether the labels are draw</span> <span class="c"># over the line segments of the contour, removing the lines beneath</span> <span class="c"># the label</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">CS</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">contour</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="n">Z</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">clabel</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">inline</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">fontsize</span><span class="o">=</span><span class="mi">10</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Simplest default with labels'</span><span class="p">)</span> <span class="c"># You can force all the contours to be the same color.</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">CS</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">contour</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="n">Z</span><span class="p">,</span> <span class="mi">6</span><span class="p">,</span> <span class="n">colors</span><span class="o">=</span><span class="s">'k'</span><span class="p">,</span> <span class="c"># negative contours will be dashed by default</span> <span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">clabel</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">fontsize</span><span class="o">=</span><span class="mi">9</span><span class="p">,</span> <span class="n">inline</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Single color - negative contours dashed'</span><span class="p">)</span> <span class="c"># You can set negative contours to be solid instead of dashed:</span> <span class="n">matplotlib</span><span class="o">.</span><span class="n">rcParams</span><span class="p">[</span><span class="s">'contour.negative_linestyle'</span><span class="p">]</span> <span class="o">=</span> <span class="s">'solid'</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">CS</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">contour</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="n">Z</span><span class="p">,</span> <span class="mi">6</span><span class="p">,</span> <span class="n">colors</span><span class="o">=</span><span class="s">'k'</span><span class="p">,</span> <span class="c"># negative contours will be dashed by default</span> <span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">clabel</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">fontsize</span><span class="o">=</span><span class="mi">9</span><span class="p">,</span> <span class="n">inline</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Single color - negative contours solid'</span><span class="p">)</span> <span class="c"># And you can manually specify the colors of the contour</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">CS</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">contour</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">Y</span><span class="p">,</span> <span class="n">Z</span><span class="p">,</span> <span class="mi">6</span><span class="p">,</span> <span class="n">linewidths</span><span class="o">=</span><span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="o">.</span><span class="mi">5</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="o">.</span><span class="mi">5</span><span class="p">),</span> <span class="n">colors</span><span class="o">=</span><span class="p">(</span><span class="s">'r'</span><span class="p">,</span> <span class="s">'green'</span><span class="p">,</span> <span class="s">'blue'</span><span class="p">,</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">0</span><span class="p">),</span> <span class="s">'#afeeee'</span><span class="p">,</span> <span class="s">'0.5'</span><span class="p">)</span> <span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">clabel</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">fontsize</span><span class="o">=</span><span class="mi">9</span><span class="p">,</span> <span class="n">inline</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Crazy lines'</span><span class="p">)</span> <span class="c"># Or you can use a colormap to specify the colors; the default</span> <span class="c"># colormap will be used for the contour lines</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">im</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">imshow</span><span class="p">(</span><span class="n">Z</span><span class="p">,</span> <span class="n">interpolation</span><span class="o">=</span><span class="s">'bilinear'</span><span class="p">,</span> <span class="n">origin</span><span class="o">=</span><span class="s">'lower'</span><span class="p">,</span> <span class="n">cmap</span><span class="o">=</span><span class="n">cm</span><span class="o">.</span><span class="n">gray</span><span class="p">,</span> <span class="n">extent</span><span class="o">=</span><span class="p">(</span><span class="o">-</span><span class="mi">3</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="o">-</span><span class="mi">2</span><span class="p">,</span><span class="mi">2</span><span class="p">))</span> <span class="n">levels</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="o">-</span><span class="mf">1.2</span><span class="p">,</span> <span class="mf">1.6</span><span class="p">,</span> <span class="mf">0.2</span><span class="p">)</span> <span class="n">CS</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">contour</span><span class="p">(</span><span class="n">Z</span><span class="p">,</span> <span class="n">levels</span><span class="p">,</span> <span class="n">origin</span><span class="o">=</span><span class="s">'lower'</span><span class="p">,</span> <span class="n">linewidths</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">extent</span><span class="o">=</span><span class="p">(</span><span class="o">-</span><span class="mi">3</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="o">-</span><span class="mi">2</span><span class="p">,</span><span class="mi">2</span><span class="p">))</span> <span class="c">#Thicken the zero contour.</span> <span class="n">zc</span> <span class="o">=</span> <span class="n">CS</span><span class="o">.</span><span class="n">collections</span><span class="p">[</span><span class="mi">6</span><span class="p">]</span> <span class="n">plt</span><span class="o">.</span><span class="n">setp</span><span class="p">(</span><span class="n">zc</span><span class="p">,</span> <span class="n">linewidth</span><span class="o">=</span><span class="mi">4</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">clabel</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">levels</span><span class="p">[</span><span class="mi">1</span><span class="p">::</span><span class="mi">2</span><span class="p">],</span> <span class="c"># label every second level</span> <span class="n">inline</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">fmt</span><span class="o">=</span><span class="s">'</span><span class="si">%1.1f</span><span class="s">'</span><span class="p">,</span> <span class="n">fontsize</span><span class="o">=</span><span class="mi">14</span><span class="p">)</span> <span class="c"># make a colorbar for the contour lines</span> <span class="n">CB</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">colorbar</span><span class="p">(</span><span class="n">CS</span><span class="p">,</span> <span class="n">shrink</span><span class="o">=</span><span class="mf">0.8</span><span class="p">,</span> <span class="n">extend</span><span class="o">=</span><span class="s">'both'</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Lines with colorbar'</span><span class="p">)</span> <span class="c">#plt.hot() # Now change the colormap for the contour lines and colorbar</span> <span class="n">plt</span><span class="o">.</span><span class="n">flag</span><span class="p">()</span> <span class="c"># We can still add a colorbar for the image, too.</span> <span class="n">CBI</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">colorbar</span><span class="p">(</span><span class="n">im</span><span class="p">,</span> <span class="n">orientation</span><span class="o">=</span><span class="s">'horizontal'</span><span class="p">,</span> <span class="n">shrink</span><span class="o">=</span><span class="mf">0.8</span><span class="p">)</span> <span class="c"># This makes the original colorbar look a bit out of place,</span> <span class="c"># so let's improve its position.</span> <span class="n">l</span><span class="p">,</span><span class="n">b</span><span class="p">,</span><span class="n">w</span><span class="p">,</span><span class="n">h</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">gca</span><span class="p">()</span><span class="o">.</span><span class="n">get_position</span><span class="p">()</span><span class="o">.</span><span class="n">bounds</span> <span class="n">ll</span><span class="p">,</span><span class="n">bb</span><span class="p">,</span><span class="n">ww</span><span class="p">,</span><span class="n">hh</span> <span class="o">=</span> <span class="n">CB</span><span class="o">.</span><span class="n">ax</span><span class="o">.</span><span class="n">get_position</span><span class="p">()</span><span class="o">.</span><span class="n">bounds</span> <span class="n">CB</span><span class="o">.</span><span class="n">ax</span><span class="o">.</span><span class="n">set_position</span><span class="p">([</span><span class="n">ll</span><span class="p">,</span> <span class="n">b</span><span class="o">+</span><span class="mf">0.1</span><span class="o">*</span><span class="n">h</span><span class="p">,</span> <span class="n">ww</span><span class="p">,</span> <span class="n">h</span><span class="o">*</span><span class="mf">0.8</span><span class="p">])</span> <span class="n">plt</span><span class="o">.</span><span class="n">show</span><span class="p">()</span> </pre></div> </div> <p>Keywords: python, matplotlib, pylab, example, codex (see <a class="reference internal" href="../../faq/howto_faq.html#how-to-search-examples"><em>Search examples</em></a>)</p> </div> </div> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../genindex.html" title="General Index" >index</a></li> <li class="right" > <a 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