andrewsplot

Andrews plot

Syntax

andrewsplot(X)
andrewsplot(X,...,'Standardize',standopt)
andrewsplot(X,...,'Quantile',alpha)
andrewsplot(X,...,'Group',group)
andrewsplot(X,...,'PropName',PropVal,...)
h = andrewsplot(X,...)

Description

andrewsplot(X) creates an Andrews plot of the multivariate data in the matrix X. The rows of X correspond to observations, the columns to variables. Andrews plots represent each observation by a function f(t) of a continuous dummy variable t over the interval [0,1]. f(t) is defined for the i th observation in X as

f(t)=X(i,1)/2+X(i,2)sin(2πt)+X(i,3)cos(2πt)+

andrewsplot treats NaN values in X as missing values and ignores the corresponding rows.

andrewsplot(X,...,'Standardize',standopt) creates an Andrews plot where standopt is one of the following:

  • 'on' — scales each column of X to have mean 0 and standard deviation 1 before making the plot.

  • 'PCA' — creates an Andrews plot from the principal component scores of X, in order of decreasing eigenvalue. (See pca.)

  • 'PCAStd' — creates an Andrews plot using the standardized principal component scores. (See pca.)

andrewsplot(X,...,'Quantile',alpha) plots only the median and the alpha and (1 – alpha) quantiles of f(t) at each value of t. This is useful if X contains many observations.

andrewsplot(X,...,'Group',group) plots the data in different groups with different colors. Groups are defined by group, a numeric array containing a group index for each observation. group can also be a categorical array, character matrix, or cell array of strings containing a group name for each observation.

andrewsplot(X,...,'PropName',PropVal,...) sets optional lineseries object properties to the specified values for all lineseries objects created by andrewsplot. (See Chart Line Properties.)

h = andrewsplot(X,...) returns a column vector of handles to the lineseries objects created by andrewsplot, one handle per row of X. If you use the 'Quantile' input parameter, h contains one handle for each of the three lineseries objects created. If you use both the 'Quantile' and the 'Group' input parameters, h contains three handles for each group.

Examples

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Create Andrews Plot to Visualize Grouped Data

This example shows how to create an Andrews plot to visualize grouped sample data.

Load the sample data.

load fisheriris

Create an Andrews plot, grouping the sample data by species.

andrewsplot(meas,'group',species)

Create a second, simplified Andrews plot that only displays the median and quartiles of each group.

andrewsplot(meas,'group',species,'quantile',.25)

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