A bagplot is a method in robust statistics for visualizing two-dimensional statistical data. The bagplot allows one to visualize the location, spread, skewness, and outliers of the data set. The bagplot consists of three nested polygons, called the “bag”, the “fence”, and the “loop”. The bagplot is sometimes defined as the multidimensional (bivariate) version of the box plot. To represent correlation between different groups you can use the convex hull.