title: Plotting a graph using matlab
body: <p>I'm having problem with plotting a graph using data of a .dat file. Can someone help me out here?</p>
  
  <p>The file is saved as <code>/My Documents/filename.dat</code> and has three columns of numbers representing variables <code>X</code>, <code>Y</code> and <code>Z</code>.</p>
  
  <p>(<code>X</code> is from 45 to 90 with variation of .5
  <code>Z</code> is from .4 to .95 with variation of .05
  <code>Y</code> is the result of these 2 variables.)</p>
  
  <p>Example: (a part of data in .dat file)</p>
  
  <pre><code>48.000000 -0.000010 0.400000
  48.500000 -0.000004 0.400000
  49.000000 0.000003 0.400000
  49.500000 0.000010 0.400000
  50.000000 0.000016 0.400000
  </code></pre>
  
  <p>I want to plot a 2d graph of <code>X</code> and <code>Y</code>, and color should change according to the <code>Z</code> variable.</p>