change font size of facet titles using seaborn facetgrid heatmap
Question: Note: this is a different question than "[How can I change the font size using
seaborn FacetGrid?](http://stackoverflow.com/questions/25328003/how-can-i-
change-the-font-size-using-seaborn-facetgrid)". The methods suggested there do
not work when using a heatmap inside a facetgrid.

How can I change the font size of the facet titles when plotting heatmaps
inside a facetgrid?

The code below tries two methods, passing `fontsize=` to `set_titles()` and
wrapping the whole thing in a plotting context. As far as I can tell, neither
seems to have any effect on facet titles when using heatmap, although the
fontweight did change. Are there any other options for controlling facet title
when using heatmap?

    
    
    import pandas as pd
    import numpy as np
    import itertools
    import seaborn as sns
    
    print("seaborn version {}".format(sns.__version__))
    # R expand.grid() function in Python
    # http://stackoverflow.com/a/12131385/1135316
    def expandgrid(*itrs):
       product = list(itertools.product(*itrs))
       return {'Var{}'.format(i+1):[x[i] for x in product] for i in range(len(itrs))}
    
    methods=['method 1', 'method2', 'method 3', 'method 4']
    times = range(0,100,10)
    data = pd.DataFrame(expandgrid(methods, times, times))
    data.columns = ['method', 'dtsi','rtsi']
    data['nw_score'] = np.random.sample(data.shape[0])
    
    def facet(data,color):
        data = data.pivot(index="dtsi", columns='rtsi', values='nw_score')
        g = sns.heatmap(data, cmap='Blues', cbar=False)
    
    with sns.plotting_context(font_scale=5.5):
        g = sns.FacetGrid(data, col="method", col_wrap=2, size=3, aspect=1)
        g = g.map_dataframe(facet)
        g.set_titles(col_template="{col_name}", fontweight='bold', fontsize=18)
    

[![enter image description
here](http://i.stack.imgur.com/RBYpn.png)](http://i.stack.imgur.com/RBYpn.png)


Answer: Thanks @mwaskon, that is the answer - use `size=` when called `set_titles`.

That leads to more questions, like

  * Can you please change `set_titles` used `fontweight=` and `fontsize=` instead of `fontweight=` and `size=`? `size=` is use elsewhere for the facet height in inches. 
  * why is `sns.plotting_context` completely ineffective in this context?

