Biplot

thumb|Biplot of Iris flower data set|Fisher's iris data set. The scattered points are the input scores of observations and the arrows show the contribution of each feature to the input loading vectors. thumb|Spectramap biplot of Anderson's iris data set thumb|Discriminant analysis biplot of Fisher's Iris flower data set|iris data

Biplots are a type of exploratory graph used in statistics, a generalization of the simple two-variable scatterplot. A biplot overlays a score plot with a loading plot. A biplot allows information on both samples and variables of a data matrix to be displayed graphically. Samples are displayed as points while variables are displayed either as vectors, linear axes or nonlinear trajectories. In the case of categorical variables, category level points may be used to represent the levels of a categorical variable. A generalised biplot displays information on both continuous and categorical variables.