an ES2015 fork of @syntagmatic's nice Baseball Scatterplot Matrix
this iteration also adds an slider to adjust the fill-opacity
or the SVG circles used as scatterplot marks. The bl.ocks:
helped me debug the HTML5 <input type='range'>
element I use for the slider control.
Scatterplot matrix design invented by J. A. Hartigan and described in his 1975 paper Printer graphics for clustering. 1986 baseball statistics data from the R package Visualizing Categorical Data.
Based on Scatterplot Matrix Brushing, but still awaiting the d3.v4 brush component.
forked from micahstubbs's block: Baseball Scatterplot Matrix II
https://d3js.org/d3.v4.0.0-alpha.35.js
https://npmcdn.com/babel-core@5.8.34/browser.min.js