title: Plotting a circle-matplotlib
body: <p>I am trying to plot a circle on a grid. The code that I have written is as follows:</p>
  
  <pre><code>import pyplot as plt
  from pyplot import Figure, subplot
  
  fig=plt.figure(1)
  plt.axis([0,400,0,400])
  ax=fig.add_subplot(1,1,1)
  circ=plt.Circle((200,200), radius=10, color='g', fill=False)
  ax.add_patch(circ)
  plt.show()
  </code></pre>
  
  <p>Now, I want the center of the circle to be the center of the graph, that is, <strong>(200,200)</strong> in this example. In case of other cases I want it to automatically choose the centre depending on the size that us set. Can this be in some way?</p>
  
  <p>To make it clearer I want to get the x-axis and the y-axis range so as to find the mid point of the grid. How do I proceed?</p>