title: Polar plot thetagrid label
body: <p>I am trying to draw a polar plot using following script. I would like to have angle of the thetagrid labels align with the grid line. (as shown in the figure)</p>
  
  <p>I have modified the code according to tom's answer. The labels of the left half of the plot appears to be upside down. </p>
  
  <pre><code>from pylab import *
  fig = figure()
  rc('grid', color='r', linewidth=0.5, linestyle='-')
  data1 = loadtxt("1.dat")
  ax = plt.subplot(111,polar=True)
  x= data1[:,0]
  y= data1[:,1]
  plt.scatter(x,y, s=0.1,color='r' )
  gl, gt = ax.set_rgrids(range(10,81,10))
  for l in gl: l.set_ls('') 
  (lines,labels)=thetagrids( range(0,360,18), ("AA", "BB", "CC", "DD", "EE", "FF", "GG", "HH", "II", "KK", "LL","MM","NN","OO","PP","QQ","RR","SS","TT","UU","VV"))
  for label,angle in zip(labels,range(0,360,18)):
      label.set_rotation(90-angle)
      ax.set_theta_offset(np.pi/2.0)
      ax.set_theta_direction(-1)
      ax.set_yticklabels([])
      show()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/vUa2w.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vUa2w.png" alt="enter image description here"></a></p>