title: Problems while making scatter plot
body: <p>Hello everyone,
                 I am trying to show the track of a tropical cyclone by using a scatter plot over a spatial plot containing sst. Now while plotting the track the scatter doesn't seem to plot all the plots, mostly it is seen over land its not plotting the points. I am not able to make out where I am doing wrong in my code, if anyone can help in this regard it will be much appreciated. I am posting part of my code along with the lat long values and the plot which I have generated.I am giving the lat long data as text as below:</p>
  
  <pre><code>Lat Lon grade
  10.4 87 D
  10.9 86.3 D
  10.9 86.3 CS
  11.1 86.1 CS
  11.4 86 CS
  11.5 86 SCS
  12 86 VSCS
  12.5 86.1 VSCS
  13.2 86.3 ESCS
  13.4 86.2 SuCS
  14   86.3 SuCS
  14.9 86.5 SuCS
  15.6 86.7 SuCS
  16.5 86.9 ESCS
  17.4 87 ESCS
  18.4 87.2 ESCS
  19.1 87.5 ESCS
  20.6 88 ESCS
  21.9 88.4 VSCS
  23.3 89 SCS
  24.2 89.3 CS
  25 89.6 DD
  25.4 89.6 D
  
  
  
  cs=map.contourf(x,y,plt_data,clevels,cmap=plt.cm.jet)#,clevels,cmap=plt.cm.jet)
      map.colorbar(cs)
  
  df = pd.read_excel('E:/bst_trc.xls',sheet_name='Sheet6')
  colors = {'SuCS': 'red', 'ESCS': 'blue', 'SCS': 'green', 'D': 'black', 'VSCS': 'orange', 'DD':'cyan', 
                'CS': 'magenta'}
  
  df['x'], df['y'] = map(list(df['Lon']), list(df['Lat']))
  for grade in list(df['grade'].unique()):
  ax.scatter(df[df['grade'] == grade]['x'],
             df[df['grade'] == grade]['y'],
             s = 50,
             label = grade,
             facecolors = colors[grade])
  
  plt.plot(df['x'], df['y'], 'k-', lw = 1.5)
  ax.legend(loc='upper center', bbox_to_anchor=(0.5, -0.05),
        fancybox=True, shadow=True, ncol=7)
  #plt.savefig('E:/Super_cyclone/Amphan/sst_bfr.tif', bbox_inches='tight', dpi=300)
  plt.show()
  </code></pre>
  
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