title: in a scatter plot, make each grid cell as a square in matplotlib in python 3.2
body: <p>I need to plot a 2D scatter from matplotlib in python 3.2.</p>
  
  <p>But, the max and min values of data are verious greatly. </p>
  
  <p>I need to adjust the grid and tickers so that each grid cell is a square and the number of grid lines connected to tickers should depend on the size of the figure.</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I prefer n X n grid lines on X and Y axis respectively. 
  The value of n depends on the max value of X and Y. I want to keep n within 3 to 8. It means that there are not more than 8 grid lines and not less than 3 lines on X and Y direction.</p>
  
  <hr>
  
  <p>My python ocde: </p>
  
  <pre><code>    #yList is a list of float numbers
      #xList is a list of float numbers
  
      rcParams['figure.figsize'] = 6, 6
      plt.scatter(xList, yList, s=3, c='g', alpha=0.5)
      plt.Figure(figsize=(1,1), facecolor='w')
      plt.ylim(0, max(yList))
      plt.xlim(0, max(xList))
  
      plt.grid()
      plt.show()
  </code></pre>
  
  <p>Currently, each grid cell is rectagular. I need square for each cell.</p>