Stacking area charts to discover emerging trends

Stacked area charts are great visualizations to discover emerging trends, especially in the marketplace. It is a common choice to show the percentage of the market share for things such as internet browsers, cell phones, or vehicles.

In this recipe, we will use data gathered from the popular website meetup.com. Using a stacked area chart, we will show membership distribution between five data science-related meetup groups.

How to do it…

1. Read in the meetup dataset, convert the join_date column into a Timestamp, and set it as the index:

   >>> meetup = pd.read_csv('data/meetup_groups.csv',
   ...     parse_dates=['join_date'],
   ...     index_col='join_date')
   >>> meetup
                                              group  ... country
   join_date                                         ...
   2016-11-18 02:41:29     houston machine learning  ...      us
   2017-05-09 14:16...