title: Cartopy: subsetting features for plotting a specific river
body: <p>Working in <code>Python3</code> with <code>cartopy</code>, I am trying to subset and plot a specific river from the Natureal Earth database.</p>
  
  <p>It is quite straightforward to plot <em>all</em> the rivers and then set the extent over a particular area:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import cartopy.crs as ccrs
  import cartopy.feature
  
  rivers = cartopy.feature.NaturalEarthFeature(
      category='physical', name='rivers_lake_centerlines',
      scale='10m', facecolor='none', edgecolor='blue')
  
  fig, ax = plt.subplots(
      nrows=1, ncols=1, subplot_kw={'projection': ccrs.PlateCarree()},
                           figsize=(10,6))
  ax.add_feature(rivers, linewidth=1)
  ax.set_extent([-65, -45, -40, -17.5])
  plt.show()
  </code></pre>
  
  <p>(Results shown below)</p>
  
  <p>However, if I wish to plot only a particular river (for purposes of illustration the Paraná, which is named <code>Paran?</code> in the data due to encoding issues, there doesn't seem to be a clear way to do this <a href="http://scitools.org.uk/cartopy/docs/latest/matplotlib/feature_interface.html" rel="nofollow noreferrer">The cartopy Feature interface documentation</a></p>
  
  <p><a href="https://i.stack.imgur.com/b9f5l.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/b9f5l.png" alt="Resulting plot"></a></p>