Using alpha shapes to group or “encircle” sets of points.
It’s not fast, but it’s fun.
DISCLAIMER: this code is quite hackish, don’t copy it blindly.
TODO: buffer the shapes so that they nicely enclose dots as ggplot2’s geom_encircle function does.
The scatterplot matrix visualizations pairwise correlations for multi-dimensional data; each cell in the matrix is a scatterplot. This example uses Anderson’s data of iris flowers on the Gaspé Peninsula. Scatterplot matrix design invented by J. A. Hartigan; see also R and GGobi. Data on Iris flowers collected by Edgar Anderson and published by Ronald Fisher.
S Forked from mbostock’s Scatterplot Matrix Brushing.