stars {base} | R Documentation

## Star Plots and Segment Diagrams of Multivariate Data

### Description

Star plots or segment diagrams are created on the current graphics device.

### Usage

    stars(x, full = TRUE, scale = TRUE, radius = TRUE,
          labels = dimnames(x)[[1]],
          locations = NULL, xlim = NULL, ylim = NULL, len = 1,
          colors = NULL, key.loc = NULL, key.labels = NULL, key.xpd = TRUE,
          draw.segments = FALSE,
          axes = FALSE, cex = 0.8, lwd = 0.25, ...)

### Arguments

`x` | matrix of data. One segment plot will be produced for each row of the matrix. Missing values (`NA`) are allowed, but they are treated as if they were 0.
`full` | logical flag: if `TRUE`, the segment plots will occupy a full circle. Otherwise, they occupy the (upper) semicircle only.
`scale` | logical flag: if `TRUE`, the columns of the data matrix are scaled independently so that the maximum value in each column is 1 and the minimum is 0. If `FALSE`, the presumption is that the data have been scaled by some other algorithm to the range [0,1].
`radius` | logical flag: in `TRUE`, the radii corresponding to each variable in the data will be drawn.
`labels` | vector of character strings for labeling the plots. Unlike the S function `stars`, no attempt is made to construct labels if `labels = NULL`.
`locations` | two column matrix with the x and y coordinates used to place each of the segment plots. If `locations` is `NULL` the segment plots will be placed in a rectangular grid.
`xlim` | vector with the range of x coordinates to plot.
`ylim` | vector with the range of y coordinates to plot.
`len` | scale factor for the length of radii or segments.
`colors` | vector of integers, each of which specifies a color for one of the segments. Ignored if `draw.segments = FALSE`
`key.loc` | vector with x and y coordinates of the unit key.
`key.labels` | vector of character strings for labeling the segments of the unit key. If omitted, the second component of `dimnames(x)` is used, if available.
`key.xpd` | clipping switch for the unit key (drawing and labeling), see `par("xpd")`.
`axes` | logical flag: if `TRUE` axes are added to the plot.
`cex` | character expansion factor for the labels.
`lwd` | line width used for drawing.
`...` | further arguments, passed to the first call of `plot()`, see `plot.default`.

### Details

Missing values are treated as 0.

Each star plot or segment diagram represents one row of the input `x`. Variables (columns) start on the right and wind counterclockwise around the circle. The size of the (scaled) column is shown by the distance from the center to the point on the star or the radius of the segment representing the variable.

Only one page of output is produced.

### Note

This code started life as spatial star plots by David A. Andrews. See http://www.udallas.edu:8080/~andrews/software/software.html.

### Author(s)

Thomas S. Dye

### Examples

    data(mtcars)
    stars(mtcars[, 1:7], key.loc = c(12, 2),
          main = "Motor Trend Cars", full = FALSE)

    stars(mtcars[, 1:7], len = 0.8, key.loc = c(12, 1.5),
          main = "Motor Trend Cars", draw.segments = TRUE)

    data(USJudgeRatings)
    stars(USJudgeRatings, labels = abbreviate(case.names(USJudgeRatings)),
          key.loc = c(13, 1.5), main = "Judge not ...", len = 0.8)