Encodings that map abstract data to visual representation.

d3-scale

Fil thanks for this excellent tutorial. I found this to be a much more enjoyable read than many d3 notebooks out there. Clear, nicely flowed, and with well chosen examples.

Wenbo Tao

Suggestion: This example might be a little clearer if the method was named "fourth" or even "quarter" instead of four, given that "four" is also in the domain array. 

I had a little bit of confusion looking at the table below/immediately understanding "four(v)", since I tend not to pay much attention to cell/var names in these example notebooks. (A consequence I think of not seeing const or let in front of them.)