title: python 2.7 matplotlib pylab : My plot is empty. How can I make the data points show up in the plot?
body: <p>I just want to plot a few coordinate values. I got the data from a dictionary. I converted the dictionary to a data frame with the pandas package. Then I extracted 2 lists from the data frame which I now want to plot. </p>
  
  <p>The plot window shows up. Even with the right axes range but the values are not plotted. Python doesn't give an error when running the code. What do I not see?</p>
  
  <pre><code>from pandas import DataFrame
  import pandas as pd
  import matplotlib.pylab as plt
  import numpy as np
  import matplotlib as mpl
  import matplotlib.pylab as plt
  import matplotlib.dates as mdates
  from matplotlib.font_manager import FontProperties
  from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
  from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg as NavigationToolbar
  import matplotlib.gridspec as gridspec
  from station_coordinates import station_coordinates 
  
  
  def plot_coords(xcoord,ycoord):
  
          plt.plot(xcoord,ycoord, marker='o', ms = 10, linestyle='', alpha=.0, color='b')[0]
          plt.xlabel('UTM x-coordinate')
          plt.ylabel('UTM y-coordinate')
  
          x_legend = np.nanmax(xcoord) + 0.01*(np.nanmax(xcoord)-np.nanmin(xcoord))
          y_legend = np.nanmin(ycoord) - 0.01*(np.nanmax(ycoord)-np.nanmin(ycoord))
          map_size = np.sqrt(pow(np.nanmax(xcoord)-np.nanmin(xcoord),2)+pow(np.nanmax(ycoord)-np.nanmin(ycoord),2) )
  
          print len(xcoord)
          print len(ycoord)
          plt.show()                                     
  
  """
  
  df      is the result of using the pandas package to rearrange the coords dictionary.
  """    
  
  coords = station_coordinates.get_coordinates_all('mikkel')
  
  df = pd.DataFrame(coords,index=['UTM X','UTM Y','depth']) 
  df = DataFrame.transpose(df)
  xcoord = df['UTM X'].values.tolist() 
  ycoord = df['UTM Y'].values.tolist()
  
  print xcoord
  print plot_coords(xcoord,ycoord)
  </code></pre>