title: Scatterplot with point colors representing a continuous variable in seaborn FacetGrid
body: <p>I am trying to generate multi-panel figure using seaborn in python and I want the color of the points in my multi-panel figure to be specified by a continuous variable. Here's an example of what I am trying to do with the "iris" dataset:</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  import seaborn as sns
  import matplotlib as mpl
  import matplotlib.pyplot as plt
  iris = sns.load_dataset('iris')
  
  g = sns.FacetGrid(iris, col = 'species', hue = 'petal_length', palette = 'seismic')
  g = g.map(plt.scatter, 'sepal_length', 'sepal_width', s = 100, alpha = 0.5)
  g.add_legend()
  </code></pre>
  
  <p>This makes the following figure:
  <a href="https://i.stack.imgur.com/SFhws.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SFhws.png" alt="iris_continuous"></a></p>
  
  <p>Which is nice, but the legend is way too long. I'd like to sample out like 1/4 of these values (ideally) or barring that display a colorbar instead.
  For instance, something like this might be acceptable, but I'd still want to split it over the three species.</p>
  
  <pre><code>plt.scatter(iris.sepal_length, iris.sepal_width, alpha = .8, c = iris.petal_length, cmap = 'seismic')
  cbar = plt.colorbar()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/RCnht.png" rel="noreferrer"><img src="https://i.stack.imgur.com/RCnht.png" alt="one panel"></a></p>
  
  <p>Any idea about how I can get the best of both of these plots?</p>
  
  <p>Edit:
  This topic seems like a good start.</p>
  
  <p><a href="https://github.com/mwaskom/seaborn/issues/582" rel="noreferrer">https://github.com/mwaskom/seaborn/issues/582</a></p>
  
  <p>Somehow, for this user, simply appending plt.colorbar after everything else ran seemed to somehow work. Doesn't seem to help in this case though.</p>