gplotmatrix (x, y, group) creates a matrix of scatter plots. Each subplot in the resulting figure is a scatter plot of a column of x against a column of y. If x is n-by-p and y is n-by-q, the resulting figure holds a q-by-p grid of subplots; the subplot in row i and column j plots x(:,j) on the horizontal axis against y(:,i) on the vertical axis. Points are grouped and colored according to group, which is a grouping variable (numeric, logical, character, string, or cell array of strings) with one entry per row of x.

gplotmatrix (x, [], group) is equivalent to gplotmatrix (x, x, group) except that the diagonal of the p-by-p grid is replaced by grouped histograms of the columns of x.

The appearance of the plot is controlled by further positional arguments:

clr

Marker colors, given as a character vector of color specifiers (e.g. "rgb") or as a matrix of RGB triplets, one row per group. Colors cycle if fewer are supplied than there are groups.

sym

Marker symbols, given as a character vector (e.g. "o+x"); defaults to ".". Symbols cycle if fewer are supplied than there are groups.

siz

Marker sizes, given as a numeric vector. Sizes cycle if fewer are supplied than there are groups.

doleg

Either "on" (default) to display a legend of the groups or "off" to suppress it.

dispopt

Controls the diagonal of the grid when y is empty: "stairs" (default) for grouped stairstep histograms, "hist" or "grpbars" for grouped bar histograms, "none" to leave the diagonal empty, or "variable" to write the variable names on the diagonal.

xnam, ynam

Character vectors or cell arrays of strings giving the names of the columns of x and y, used to label the outer axes.

An optional leading parent argument (a figure or uipanel handle) selects the container for the plot.

The optional outputs are h, an array of handles to the plotted objects with size ny-by-p-by-k (where ny is the number of rows of the grid and k the number of groups); ax, the matrix of handles to the subplot axes (with an extra row of hidden axes for the diagonal histograms); and bigax, the handle to the invisible enclosing axes used for titles and labels.

See also: gscatter, plotmatrix, grpstats

Source Code: gplotmatrix