Prompt for March 29

For contour mapping (whether using geography or not), it's better to keep the TopoJSON import around.

More on d3.contour. Here is a contour example and a density example.

In addition to the fast food dataset from Friday, today's data come from a subsample of a Kaggle dataset of all recorded NHL game events for the 2019-2020 season.

HTML for today:
Code for today: